HIGH PRESSURE PUMP WITH SEPARATE CLEAN AND DIRTY FLUID CIRCUITS

Abstract

Implementations described herein relate to apparatus and methods for using a membrane pump to establish fracking pressure. Apparatus described herein includes, in place of mechanical pumps such as piston and impeller pumps, one or more membrane pumps are employed in a fluid circuit to increase the pressure of the fracking fluid. In operation of this system, a clean fluid circuit is used to pressurize clean fluid, transfer that pressure into the dirty fluid, and then return the clean fluid to a storage, and a dirty fluid circuit flows the dirty fluid from a storage, to the membrane pump to be pressurized, and then into a well bore to pressurize a formation penetrated by the well bore.

Claims

1. A fracking fluid pressurization system, comprising; a dirty fluid inlet line connected to a dirty fluid source at a first pressure; a dirty fluid outlet line connectable to a well bore; a clean fluid inlet line connected to a clean fluid source at a second pressure greater than the first pressure; a clean fluid return line maintainable at a pressure less than the first pressure; a membrane pump comprising; a body having a hollow interior; and a membrane within the hollow interior of the body, dividing the hollow interior into a first volume and a second volume, the first and second fluid volumes isolated from one another by the membrane; a dirty fluid inlet in fluid communication with the dirty fluid inlet line and the first volume; a dirty fluid inlet check valve fluidly interposed between dirty fluid inlet line and the dirty fluid inlet; a dirty fluid outlet in fluid communication with the first volume and the dirty fluid outlet line; a dirty fluid outlet check valve fluidly interposed between dirty fluid outlet line and the dirty fluid outlet; a clean fluid inlet in fluid communication with the second volume; an inlet user position selectable valve fluidly interposed between the clean fluid inlet line and the clean fluid inlet; a clean fluid outlet in fluid communication with the second volume; and an outlet user position selectable valve fluidly interposed between the clean fluid outlet and the clean fluid outlet line.

2. The fracking fluid pressurization system in claim 1, further comprising a dirty fluid pump the output of which is at the first pressure.

3. The fracking fluid pressurization system in claim 1, wherein the dirty fluid pump mixes the proppant with a fluid.

4. The fracking fluid pressurization system in claim 2, further comprising a clean fluid pump the output of which is at the second pressure.

5. The fracking fluid pressurization system in claim 1, wherein the clean fluid outlet is in fluid communication with a fluid tank and the clean fluid inlet is in fluid communication with the fluid tank.

6. The fracking fluid pressurization system in claim 5, further comprising a fluid chiller interposed between the clean fluid outlet and the fluid tank.

7. The fracking fluid pressurization system in claim 5, further comprising a pressure regulator interposed between the clean fluid pump and the inlet user position selectable valve.

8. A method for establishing a fracking pressure in a dirty fluid including a proppant therein, comprising providing a membrane pump comprising; a body having a hollow interior; and a membrane within the hollow interior of the body, dividing the hollow interior into a first volume and a second volume, the first and second fluid volumes isolated from one another by the membrane; providing a dirty fluid inlet in fluid communication with the dirty fluid inlet line and the first volume; providing a dirty fluid inlet check valve fluidly interposed between dirty fluid inlet line and the dirty fluid inlet; providing a dirty fluid outlet in fluid communication with the first volume and the dirty fluid outlet line; providing a dirty fluid outlet check valve fluidly interposed between dirty fluid outlet line and the dirty fluid outlet; providing a clean fluid inlet in fluid communication with the second volume; providing an inlet user position selectable valve fluidly interposed between the clean fluid inlet line and the clean fluid inlet; providing a clean fluid outlet in fluid communication with the second volume; and providing an outlet user position selectable valve fluidly interposed between the clean fluid outlet and the clean fluid outlet line, preparing a dirty fluid comprising water, chemistry, proppant, from a water, chemistry, and proppant source, pumping, using a low-pressure pump, the dirty fluid into the first volume of the membrane pump; and pumping, a clean fluid from a clean fluid source, using a high-pressure pump to pump the clean fluid into the second volume of the membrane pump, wherein; the clean fluid in the membrane pump pushing the dirty fluid in the membrane pump out of the membrane pump toward a well bore.

9. The method for establishing a fracking pressure in a dirty fluid including a proppant therein in claim 8, further comprising a dirty fluid pump the output of which is at the first pressure.

10. The method for establishing a fracking pressure in a dirty fluid including a proppant therein in claim 8, wherein the dirty fluid pump mixes the proppant with a fluid.

11. The method for establishing a fracking pressure in a dirty fluid including a proppant therein 9, further comprising a clean fluid pump the output of which is at the second pressure.

12. The method for establishing a fracking pressure in a dirty fluid including a proppant therein in claim 8, wherein the clean fluid outlet is in fluid communication with a fluid tank and the clean fluid inlet is in fluid communication with the fluid tank.

13. The method for establishing a fracking pressure in a dirty fluid including a proppant therein in claim 12, further comprising a fluid chiller interposed between the clean fluid outlet and the fluid tank.

14. The method for establishing a fracking pressure in a dirty fluid including a proppant therein in claim 12, further comprising a pressure regulator interposed between the clean fluid pump and the inlet user position selectable valve.

15. A method of providing a dirty fluid therein a dirty fluid including a proppant therein to a well bore deadheaded to a formation to be fractured, comprising: providing a pump housing having a membrane therein separating the interior of the pressure vessel into a first fluid side and a second fluid side, the housing having an internal housing volume therein; providing a dirty fluid inlet in fluid communication with the dirty fluid inlet line and the first fluid side; and providing a dirty fluid inlet check valve fluidly interposed between dirty fluid inlet line and the dirty fluid inlet; providing a dirty fluid outlet in fluid communication with the first fluid side and the dirty fluid outlet line; providing a dirty fluid outlet check valve fluidly interposed between dirty fluid outlet line and the dirty fluid outlet; providing a clean fluid inlet in fluid communication with the second fluid side; providing an inlet user position selectable valve fluidly interposed between the clean fluid inlet line and the clean fluid inlet; providing a clean fluid outlet in fluid communication with the second fluid side; and providing an outlet user position selectable valve fluidly interposed between the clean fluid outlet and the clean fluid outlet line, preparing a dirty fluid comprising water, chemistry, proppant, from a water, chemistry, and proppant source, pumping, using a low-pressure pump, the dirty fluid into the first fluid side of the membrane pump to establish a full internal housing volume of dirty fluid within the housing, pumping, a clean fluid from a clean fluid source, using a high-pressure pump to pump the clean fluid into the second fluid side of the membrane pump, wherein; the clean fluid in the membrane pump pushes the full internal housing volume of dirty fluid in the housing out of the housing toward the well bore.

16. The method of providing a dirty fluid including a proppant therein to a well bore deadheaded to a formation to be fractured of claim 15, wherein after pumping the clean fluid in the housing to push the full internal housing volume of dirty fluid in the housing out of the housing toward the well bore refilling the first fluid side of the housing with dirty fluid.

17. The method of providing a dirty fluid including a proppant therein to a well bore deadheaded to a formation to be fractured of claim 15, further comprising providing a dirty fluid pump outputting dirty fluid at a first pressure, wherein; the refilling of the first fluid side of the housing with the dirty fluid is provided by opening the outlet user position selectable valve to expose the clean fluid in the second fluid side of the housing to a pressure lower than the first pressure, whereby the pressure in the dirty fluid in the first fluid side is reduced to a pressure less than the first pressure and the dirty inlet check valve opens to allow dirty fluid from the dirty fluid pump to enter the first fluid side.

18. The method of providing a dirty fluid including a proppant therein to a well bore deadheaded to a formation to be fractured of claim 17, further comprising providing a clean fluid pump outputting dirty fluid at a second pressure, wherein; the refilling of the second fluid side of the housing with the clean fluid is provided by opening the inlet user position selectable valve to expose the dirty fluid in the first fluid side of the housing to a pressure greater than the first pressure, whereby the pressure in the dirty fluid in the first fluid side is increased to a pressure sufficient to close the dirty inlet check valve and open the dirty fluid outlet check valve.

19. The method of providing a dirty fluid including a proppant therein to a well bore deadheaded to a formation to be fractured of claim 18, whereby the pressure in the dirty fluid in the first fluid side is increased to a pressure sufficient to close the dirty inlet check valve and thereafter open the dirty fluid outlet check valve.

20. The method of providing a dirty fluid including a proppant therein to a well bore deadheaded to a formation to be fractured of claim 18, further comprising providing a dirty fluid outlet manifold fluidly connecting between the dirty fluid outlet check valve and a well bore.

21. A drilling mud pump, comprising: a drilling mud fluid inlet line connected to a drilling mud source at a first pressure; a mud outlet line connectable to a borehole; a clean fluid inlet line connected to a clean fluid source at a second pressure greater than the first pressure; a clean fluid return line maintainable at a pressure less than the first pressure; a membrane pump comprising; a body having a hollow interior; and a membrane within the hollow interior of the body, dividing the hollow interior into a first volume and a second volume, the first and second fluid volumes isolated from one another by the membrane; a drilling mud inlet in fluid communication with the drilling mud inlet line and the first volume; a drilling mud inlet check valve fluidly interposed between drilling mud inlet line and the drilling mud inlet; a drilling mud outlet in fluid communication with the first volume and the drilling mud outlet line; a drilling mud outlet check valve fluidly interposed between drilling mud outlet line and the drilling mud outlet; a clean fluid inlet in fluid communication with the second volume; an inlet user position selectable valve fluidly interposed between the clean fluid inlet line and the clean fluid inlet; a clean fluid outlet in fluid communication with the second volume; and an outlet user position selectable valve fluidly interposed between the clean fluid outlet and the clean fluid outlet line.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, may admit to other equally effective embodiments.

[0007] FIG. 1 illustrates a schematic view of a fracking circuit featuring a membrane pump.

[0008] FIG. 2 illustrates a sectional view of a membrane pump of the fracking circuit of FIG. 1 at a resting state.

[0009] FIG. 3 illustrates a sectional view of a membrane pump of the fracking circuit of FIG. 1 at a state in which the first volume is being filled.

[0010] FIG. 4 illustrates a sectional perspective view of a membrane pump of the fracking circuit of FIG. 1 at a state in which the first volume is full.

[0011] FIG. 5 illustrates a sectional view of a membrane pump of the fracking circuit of FIG. 1 at a state in which the second volume is being filled

[0012] FIG. 6 illustrates a sectional view of a membrane pump of the fracking circuit of FIG. 1 at a state in which the second volume is being filled and the first volume is being emptied.

[0013] FIG. 7 illustrates a sectional view of a membrane pump of the fracking circuit of FIG. 1 at a state in which the second volume is full and the first volume is empty.

[0014] FIG. 8 illustrates a schematic view of a drilling mud fracking circuit featuring a membrane pump.

[0015] FIG. 9 illustrates a mobile fracking pump system.

[0016] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.

DETAILED DESCRIPTION

[0017] Herein, in place of mechanical pumps such as piston and impeller pumps, one or more membrane pumps are employed in a fluid circuit to increase the pressure of a dirty fluid, for example the fracking fluid, for injection into a subterranean formation. As used herein, a dirty fluid is a fluid that contains solids and particulates that are known to cause wear of or on, or degrade, mechanical pumps, for example wear or degradation of piston pump surfaces, When this wear or degradation occurs, the isolation between the high and low pressure regions of the pumps, separated by seals, may fail and prevent the pump from achieving the desired outlet pressure of the fluid from the pump. By using a membrane pump, a clean fluid, for example water without solids purposely added thereto, is pressurized using a traditional mechanical pumping apparatus, and this fluid is used to pressurize the dirty, proppant containing, fracking fluid, without intermingling of the two fluids, i.e., without commingling of the dirty and clean fluids. As a result, the only moving part of the pump in contact with the dirty fluid is the membrane, and movement thereof, caused by differential pressure thereacross, is used to pressurize the dirty fracking fluid. Multiple membrane pumps can be employed to service a fracking unit, and by the provision of check valves on the inlets and outlets of each of the dirty fluid and clean fluid into the pump, the dirty fracking fluid is pressurized using a minimum of moving pump parts exposed to the dirty fracking fluid. In operation of this system, a clean fluid circuit is used to pressurize clean fluid, i.e., a fluid such as water that has not had a proppant added thereinto, and transfer that pressure into the dirty fluid in the pump, and then return the clean fluid to a storage. A dirty fluid circuit is configured to transfer or flow the dirty fluid, i.e., a fluid such as water to which proppants and chemicals such as surfactants are added, from a fluid storage to the membrane pump to be pressurized, and then into a well bore to pressurize a subterranean formation penetrated by the well bore. Valves in the fracking fluid circuit are used to isolate the dirty fluid being pressurized from communication with the well bore until the pressure thereof is raised to a level above the pressure in the wellbore. Thus, the pressure in the well bore can be raised in stepwise fashion using one or more pumps. Once the fracturing of the formation is completed, the dirty fluid is allowed to flow out of the well bore and is collected for recycling or other disposition thereof.

[0018] A fracking fluid circuit 100 utilizing membrane pumps 110 to pressurize a fracking fluid is shown in FIG. 1. During operation of the fluid circuit to pressurize the fracking fluid, the fluid circuit components are located in close proximity to a fracking unit over a wellhead or well bore. The fracking unit includes an injection unit 101which is located adjacent to or over a well bore or wellhead of a well bore extending to a formation to be fractured. The injection unit 101 is fluidly connected to a piping connected to a ball or gate valve 103. The ball or gate valve 103 isolates flow into, or out of, the well bore and flowing through the injection unit 101. In FIG. 1, three injection units 101 are shown with each connected to the fracking fluid circuit 100 through a ball or gate valve 103 associated with, and dedicated to, each injection unit 101. A fluid flow line 90 from each of the one or more ball or gate valve(s) 103 leads to a common flow line or manifold 92 attached to a first fracture relief valve 105. The first fracture relief valve 105 allows emergency pressure relief to occur during an upset or other deleterious event during a fracking operation. The first fracture relief valve 105 is positioned between the manifold 92 leading to the one or more ball or gate valve(s) 103 and a first check valve 107 leading to one or more membrane pump(s) 110 through a high pressure dirty fluid line 94. The check valves in the fluid circuit 100 only open if there is a pressure differential between the fluid ports of the check valve sufficiently great to cause the check valves poppet or seal to move off of a seat thereof. Each of the check valves herein, unless otherwise specified, generally include a seat, a poppet which can move against the seat to seal off an opening through the seat and thus close the check valve, or move away from the seat to allow fluid to pass through the opening, and a biasing element, typically a spring, which if the pressure is the same or nearly the same on the inlet and outlet sides of the check valve, pushes the poppet against the seat to keep the check valve closed and will maintain the check valve in this closed position until the pressure difference between the inlet which ports fluid to the portion of the poppet exposed within the circumference of the seat and the and the outlet is sufficient to overcome the force of the spring biasing the poppet against the seat. When the pressure on the valve inlet causes the pressure on the inlet side of the poppet to exceed the spring force, the poppet moves away from the seat and fluid can flow through the check valve. If there is one and only one membrane pump in the fracking circuit, the inlet to the first check valve 107 is connected through the high pressure dirty fluid manifold 94 to a dirty fluid outlet check valve 108, here membrane pump 108a, connected to the dirty fluid outlet of a membrane pump 110. If there are multiple membrane pumps 110, as shown in FIG. 1 six membrane pumps 110a-f, the first check valve 107 is fluidly connected through the high pressure dirty fluid manifold 94 to multiple dirty fluid outlet check valves 108, here outlet check valves 108a-f, each membrane pump 110a-f having one dirty fluid outlet check valve 108 corresponding thereto connected between that membrane pump 110 and the high pressure dirty fluid manifold 94 connected to the first check valve 107. Although six membrane pumps 110a-f are illustrated, a lesser or greater number may be used based on user need.

[0019] Each of the one or more membrane pumps 110a-f includes a housing providing a pressure vessel capable of securely holding therein fluid at pressures of up to 15,000 or more psi, and a flexible, stretchable membrane 98 (FIG. 2), of a rubber or rubber like material) disposed therein and separating the dirty fluid volume 50 of the membrane pump 110 from the clean fluid volume 52 thereof. Each membrane pump 110a-f includes a dirty fluid inlet 54, which is controlled to be in an open or closed position by a corresponding one of the dirty fluid inlet check valves 109 (109a-f), a dirty fluid outlet 56, which is controlled to be in an open or closed position by a corresponding one of the dirty fluid outlet check valves 108 (108a-f), a clean fluid inlet 58, which is controlled to be in an open or closed position by a corresponding one of a plurality of clean fluid inlet user selectable position valves 111 (111a-f) individually associated with a one of the membrane pumps 110a-f, and a clean fluid outlet 60, which is controlled to be in an open or closed position by corresponding one of a plurality of clean fluid outlet user selectable position valves 112 (112a-f).

[0020] The dirty fluid inlet check valve 109 associated with a membrane pump 110 is fluidly connected to a low pressure dirty fluid manifold 62 leading bi-directionally therefrom. In one direction or at one end thereof, the low pressure dirty fluid manifold 62 is connectable to a fracking fluid waste receptacle 114, for example a tank trailer, and in the other direction or at the other end thereof the low pressure dirty fluid manifold 62 extends to a dirty side master check valve 115. The low pressure dirty fluid manifold 62 is here connected through the dirty side master check valve 115 to a plurality of, in this aspect, two low pressure pumps 116a and 116b. The low pressure pumps 116a,116b are each connected, on the outlet side thereof, through a fracking fluid side fluid inlet line 64 to the inlet of the dirty side master check valve 115. They are also connected, at the inlet side thereof through appropriate piping 66 or hoses, to a water source 121 and a chemistry source 122, for example a surfactant. The low pressure pumps 116a, 116b, also include a mechanism for incorporation of the proppant, for example sand, into the fluid being pumped therethrough. Here, a hopper 68 is configured to receive the proppant therein, and a screw auger, or other conveyance, intermixes the proppant with the fluid entering the inlet side of the low pressure pumps 116a, b, which fluid is then pumped to approximately 110 to 120 psi at the outlet of the low pressure pump 116a, b. The low pressure pump or pumps 116a, 116b receives or pulls chemistry, water, and proppant from the chemistry source 122, water source 121, and proppant source 120, respectively, and pressurizes the fluid mixture to flow in the direction of the dirty side master check valve 115 in the direction of the membrane pump 110 at a relatively low pressure, for example 120 psi (127 KPa).

[0021] On the clean fluid side of the fluid circuit 100, one or more high pressure pumps 133 are fluidly connected, through a high pressure clean fluid source manifold 70, to the clean fluid inlets 58 of the membrane pumps 110, and the clean fluid outlets 60 of the membrane pumps 110 are fluidly connected to a return manifold 76 to return the clean fluid back to a fluid reservoir, such as one or more water tanks 134. The clean fluid inlet 58 (58a-f) to each membrane pump 110 is controlled to be open or closed by a clean fluid inlet user selectable position valve 111 (111a-f). A clean fluid inlet line 72 extends from each of the clean fluid inlet user selectable position valves 111a-f toward and to the clean fluid source manifold 70. The clean fluid inlet user selectable position valves 111a-f are controlled by a computer to be opened or closed based upon the output of a pressure transducer or volume detector of the membrane pump 110a-f with which they are each associated. The clean fluid source manifold 70 extends from the connection thereof to the clean fluid inlet lines 72 associated with each membrane pump 110a-f, to one or a plurality of on/off valves 130. The on/off valves 130 are each connected via appropriate piping to a high pressure check valve 131. Each high pressure check valve 131 is fluidly located between the on/off valve 130 and a pressure regulator 132. Each pressure regulator 132 is connected to the outlet of a high pressure pump 133, and is set to establish the maximum pressure of the clean fluid that goes into the fluid lines leading to the membrane pumps 110, for example 15,000 p.s.i. If the fluid outlet pressure of one of the high pressure pumps 133 overshoots the maximum desired pressure, the pressure regulator 132 reduces the pressure at the outlet thereof to bring the fluid pressure of the clean fluid reaching the clean fluid inlet line 72 associated with each of the membrane pumps 110a-f within the desired pressure range.

[0022] The fluid piping for the high pressure clean fluid connects each pressure regulator 132 to a high pressure pump 133, which are each capable of compressing fluid received from the connected plurality of water tanks 134 to 15,000 psi (103.4 MPa). A series of connection lines 145 allow water to be pulled from any tank of the plurality of water tanks 134 by any of the high pressure pumps 133, and the surface of the water in the water tanks may be exposed to local ambient,. i.e., atmospheric, pressure.

[0023] A clean fluid outlet user position selectable valve 112a-f is fluidly connected between an associated one of the clean fluid outlets 60a-f, such that a single one of the clean fluid outlet user position selectable valves 112a-f is fluidly connected to a single one of the clean fluid outlets 60a-f at the inlet thereof and to the return manifold 76 at the outlet thereof. The clean fluid outlet user selectable position valves 112a-f are controlled by a computer or controller, such as an Field Gate Programmable Array or FGPA, in response to signals received from a pressure transducer or volume reader or sensor located on the clean fluid side of the inside of an associated one of the membrane pumps 110a-f. The return manifold 76 fluidly connects the clean fluid outlets 60a-f of the several membrane pumps 110a-f to a heat exchanger and water filter unit 136, from which a chilled water line 78 extends to return the clean fluid to the water tanks 134. The heat exchanger and water filter unit 136 cools the returning water and filters out any particulates larger than a user selectable size from the returning clean fluid.

[0024] Each of the membrane pumps 110a-f is configured to pressurize the dirty fluid, here a fracking fluid, and to pump it to enter the injection unit 101 and associated well bore and to pressurize the fracking fluid to a pressure on the order of 15,000 p.s.i. To allow high pressure fluid at around 15,000 psi (103.4 MPa) to be present in the well bore, fracking fluid, here a combination of water, proppant, and chemistry is pumped by the low pressure pump or pumps 116a, b to a pressure of at 110 to 120 p.s.i. (760 to 827 KPa). When the pressure in the dirty fluid side or dirty fluid volume 50 of a membrane pump 110 is less than this pressure, dirty fluid will be pumped toward the dirty side master check valve 115 in the direction of the membrane pumps 110a-f. By proper cycling of the clean fluid and the dirty fluid, the volume of dirty fluid present in a membrane pump 110a-f can be pumped toward the well bore in a continuous flow until the volume of dirty fluid in the membrane pump 110a-f is exhausted therefrom.

[0025] Referring initially to FIG. 2, the membrane pump 110 is shown at rest, or at volume equilibrium, where the volume of dirty fluid in the dirty fluid volume 50 (i.e., on the dirty fluid side of the membrane 98) and volume of clean fluid in the clean fluid volume 52 (i.e., on the clean fluid side of the membrane 98) are equal within the membrane pump. As the membrane 98 is flexible, the fluid volumes of the dirty fluid volume 50 and clean fluid volume are variable, depending on the relative pressures therein. When the pressure in the dirty fluid side of the membrane 98 is greater than that on the clean fluid side thereof, the dirty fluid volume 50 increases, while the clean fluid volume decreases, and vice versa.

[0026] To pump the dirty fluid to the high pressure needed for fracking, the dirty fluid inlet check valve 109 and the clean fluid outlet user selectable position valve 112 are open, and the dirty fluid outlet check valve and the clean fluid inlet user selectable position valve 111 are closed. In this state, the clean fluid outlet 60 is ultimately exhaustible to ambient air pressure at one or more of the water tanks 134, and hence the dirty fluid at 120 psi will push the clean fluid from the clean fluid volume 52 of the membrane pump 110, replacing the volume of clean fluid pushed out of the clean fluid volume 52 of the membrane pump 110 with a corresponding volume of dirty fluid in the dirty fluid volume 50 of the membrane pump 110. This caused the volume of the clean fluid volume to contract, and the membrane 98 moves through the position shown in FIG. 3 to that of FIG. 4, where the dirty fluid volume is nearly 100% of the internal volume of the housing 96 of the membrane pump 110 and the clean fluid volume approaches 0% of the internal volume of the housing 96 of the membrane pump 110. Once the clean fluid has been pushed out of the membrane pump 110, the pressure inside the dirty fluid volume 50 and the pressure in the low pressure dirty fluid manifold 62 will equalize, and the dirty fluid inlet check valve 109 will close as the pressure on opposed sides of it equalizes allowing the spring thereof to close the poppet against the seat thereof, isolating the dirty fluid volume 50 from the dirty fluid in the low pressure dirty fluid manifold 62. Then, the clean fluid outlet user selectable position valve 112 is closed, and the clean fluid inlet user selectable position valve 111 is opened, causing high pressure clean fluid to enter the clean fluid volume 52 and increase the pressure of the dirty fluid in the dirty fluid outlet 56. Once the dirty fluid in the dirty fluid volume 50 reaches a pressure sufficiently greater that the pressure in the high pressure dirty fluid manifold 94, to push the poppet against the spring to lift off of the seat of the dirty fluid outlet check valve 108, the dirty fluid will be pushed out of the membrane pump 110, into the high pressure dirty fluid manifold 94 and thence into the well bore, with the position of the membrane 98 moving in the sequence shown from FIG. 4 to FIG. 7. Here, the clean fluid volume 52 increases as the dirty fluid volume 50 decreases, as the dirty fluid is being forced into the high pressure dirty fluid manifold 94. Then, by again opening the clean fluid outlet user selectable position valve 112 and closing the clean fluid inlet user selectable position valve 111, the dirty fluid at 120 psi (127 KPA) will enter the dirty volume side 50 of the membrane pump 110 and push the clean fluid out of the membrane pump 110 and into the return manifold 76 toward the water tank(s) 134.

[0027] To properly cycle the valving controlling the clean fluid inlet 58 and clean fluid outlet connected to the clean fluid side or clean fluid volume 52 of the membrane pump 110, a detection paradigm for determining whether the membrane pump is full of dirty or full of clean fluid is needed. For example, as shown in FIG. 4, to sense that the membrane 98 is fully filed with dirty fluid, the membrane 98 may include a conductive surface formed or adhered thereto on the clean fluid side thereof, for example a thin metal sheet 154, and a pair of, spaced from one another, electrical contacts 156a, b, connected to a source of power and ground, respectively are provided on the inner wall of the membrane pump 110 in a location where the metal sheet 154 can come into contact with them when the dirty fluid volume 50 nears 100% of the membrane pump 110 volume.. A current or voltage detector 160 is connected to the ground path of the circuit, and the detector is readable by a controller 158. When the sheet 154 contacts both contacts, electricity flows through the sheet 154 and is detected by the detector, causing the controller to close the user selectable position valve 112 on the pump clean fluid outlet 60, and open the user selectable position valve 111 on the clean fluid inlet 58. This same sheet 154 and electrical contacts can be employed to detect when the membrane pump is at its full capacity of clean fluid, by locating a second sheet on the opposed side of the membrane 98 and the second pair of electrical contacts 156a, b, spaced form one another adjacent the dirty fluid inlet and outlet, to sense when the dirty fluid has been fully exhausted from the dirty fluid volume 50 (dirty fluid side) of the membrane pump 110.

[0028] The clean fluid inlet user selectable position valve 111, controlled by a controller 158 in response to a signal from pressure transducer, volume sensor, or membrane sensor inside of the membrane pump 110, opens in response to the membrane pump 110 filling with dirty fluid. Clean fluid is then pushed by the high pressure pump 133, which pumps fluid at a pressure of up to 15000 psi from the connected plurality of water tanks 134, into the clean fluid volume 52 side of the membrane pump. Clean fluid is pushed or flowed through the pressure regulator 132, which sets the maximum pressure that goes into the lines leading to the membrane pumps, through the high-pressure check valve 131, and through the on/off valve 130 to the clean fluid inlet 58. Clean fluid enters the membrane pump 110, causing an increase in pressure in the dirty fluid therein, this higher pressure causing closing of the dirty fluid inlet check valve 109 and opening of the dirty fluid outlet check valve 108.

[0029] In one aspect, the functionality of the inlet and outlet user selectable position valves 111, 112 can be combined in a single valve, for example a three way, two position, valve, wherein the clean fluid inlet 58 and the clean fluid outlet 60 are selectively and exclusively the clean fluid source manifold 70 and the return manifold 76 respectively. Using this valve, the clean fluid inlet 58 is fluidly connected to the clean fluid source manifold 70 when the clean fluid outlet 60 is fluidly disconnected from the return manifold 76, and the clean fluid outlet 60 is fluidly connected to the return manifold 76 only when the clean fluid inlet 58 is fluidly disconnected to the clean fluid source manifold 70.

[0030] The membrane pump 110 pushes the dirty fluid out of the dirty fluid outlet check valve 108, allowing the dirty fluid to exit the membrane pump 110 and flow into the high pressure dirty fluid line 94, through the first check valve 107, which opens in response to the high pressure fluid, through the first fracture relief valve 105, and the ball or gate valve 103 controlling access to each injection unit 101 and its associated well bore. At the beginning of the fracking process, multiple full membrane pump volumes of dirty fluid may need to be flowed into the well to form a continuous liquid column of dirty fluid between the injection unit and the formation. Thereafter, as each membrane pump 110 pumps its volume of dirty fluid into the high-pressure dirty fluid line, the pressure thereof will increase. A number of additional volumes of dirty fluid will then be pumped into the high-pressure dirty fluid manifold 94 raising the pressure therein, and at the formation, to the fracking pressure. If the pressure in the well bore or the high pressure dirty fluid manifold 94 spikes, the first fracture relief valve 105 will open to allow pressurized fluid to flow out into the atmosphere, preventing damage to the fluid circuit 100. If equilibrium is reached, i.e., the fluid pressure in the high pressure dirty fluid manifold 94 and fluid pressure in the clean fluid source inlet 70 become equal, then the pumping of the dirty fluid from the membrane pumps 110a-f will stop, but the pressure will be maintained in the high pressure dirty fluid manifold 94 at the pressure of the clean fluid source manifold 70.

[0031] The clean fluid in the membrane pump 110 exits through the clean fluid outlet 60, which is controlled to be in an open or closed state by the clean fluid outlet user selectable position valve 112. The clean fluid flows from the clean fluid outlet 60 toward the heat exchanger and water filter unit 136. The heat exchanger and water filter unit 136 cools the pressurized water to allow it to continue to flow through the clean fluid circuit as a liquid, i.e., to prevent it from gaining heat during each pressurization thereof resulting in higher and higher fluid temperature over time. The clean fluid flows from the heat exchanger and water filter unit 136 back into the plurality of water tanks 134 to be used again in the membrane pump110 to pressurize the dirty fluid.

[0032] The use of a separate dirty fluid circuit(s) and clean fluid circuit(s), in conjunction with the pumping using a membrane 98 to provide variable, isolated from one another, dirty fluid and clean fluid volumes 50, 52 within a pressure vessel, here membrane pump 110, enables fluid isolation of the lower pressure dirty fluid from the higher pressure dirty fluid, and, with proper valving, allows the inlet and outlet to the pump on the dirty fluid side thereof to automatically cycle in response the cycling of the inlet and outlet valves on the clean fluid side of the membrane 98. Additionally, within operational tolerance, the input pressure to the dirty fluid volume 50 of the membrane pump 110 remains the same pressure throughout a single operation, such as a fracking operation, using the dirty fluid. Likewise, because the dirty fluid inlet valve 109 operates as a pressure relief valve, wherein it opens solely based on the pressure differential across the inlet from the low pressure pump 116a, b and outlet to the dirty fluid volume 50 side thereof, and the spring constant of a spring therein providing a force to help maintain it in a closed position, the characteristics of filling a specific membrane pump 110 will remain relatively constant over multiple filling cycles, leading to operational stability and predictability of the fill time of the dirty fluid volume 50 of the membrane pump 110. This occurs because the vent manifold 76 pressure will be of a similar value each time the clean fluid user selectable position outlet valve 112 is opened. Thus the pressure drop in the clean fluid volume 52, and thus the dirty fluid volume 50, should be repeatable from one pumping cycle to fill and then exhaust the dirty fluid volume 50 to the next pumping cycle to fill and then exhaust the dirty fluid volume 50. On the high pressure side, the dirty fluid outlet valve 108 opens only after the clean fluid entering the clean fluid volume side 52 of the membrane pump 110 has achieved the release pressure of the dirty fluid outlet valve 108, which is a function of the pressure in the dirty fluid manifold 94 and the force of the spring holding the dirty fluid outlet valve 108 in a closed position until the pressure in the dirty fluid volume 50 of the membrane pump is equal to or slightly greater than the pressure in the high pressure dirty fluid manifold 94, at which point it opens allowing the membrane and clean fluid on the clean fluid volume 52 side of the membrane pump 110 to push the dirty fluid into the high pressure dirty fluid manifold 94. Initially, before any fluid is flowed, the pressure in the high-pressure dirty fluid manifold 94 is at or near atmospheric pressure. Once fluid is present from in the high pressure dirty fluid membrane and in the borehole to the subterranean zone where fracking is to occur, as additional dirty fluid is pushed into the high-pressure dirty fluid manifold 94 in each pumping cycle of the membrane pump 110, the pressure therein increases. Therefore, in each subsequent pumping cycle the pressure of the dirty fluid in the dirty fluid volume of the membrane pump 110 needs to reach a higher pressure to cause the dirty fluid outlet valve 108 to open. However, the difference in pressure across the membrane pump 110 side and the high-pressure dirty fluid manifold 94 sides of the dirty fluid outlet valve remains the same for each cycle. Thus, where a single membrane pump 110 is used to charge the high pressure dirty fluid manifold 94 with dirty fluid, the pressure in the high pressure dirty fluid manifold 94 will rise in a step wise fashion, the dirty fluid in the high pressure dirty fluid manifold 94 maintaining its pressure at a first pressure during fill cycles of the membrane pump 110 with dirty fluid, increasing in pressure as the manifold pump 110 operates to push the dirty fluid therefrom into the high pressure dirty fluid manifold 94 to achieve a second pressure higher than the first pressure, and maintaining that second pressure during another fill cycle of the membrane pump 110 with dirty fluid. Thus, the pressure in the high-pressure dirty fluid manifold 94 will rise in a step wise fashion until the desired pressure therein is reached, while the pressure in the low-pressure dirty fluid manifold 62 remains relatively constant. Where multiple membrane pumps 110 are employed, they can each independently pump dirty fluid into the high pressure dirty fluid manifold 94, which will occur when the pressure of the dirty fluid in the dirty fluid volumes of the membrane pumps 100 are greater than that in the high pressure dirty fluid manifold 94, either simultaneously with one another, in time separated pumping's from one another, or with overlaps in their pumping periods into the high pressure dirty fluid manifold 94.

[0033] In one aspect, the high pressure fluid delivery capability enabled herein is portably mounted, and can be deployed to a site requiring a source of dirty high pressure fluid, connected to any local fluid connections, such as fluid sources and a fluid delivery locale, and after the need for the high pressure fluid capability is over, disconnected from the local fluid connections and redeployed or moved to storage. For example, as shown in FIG. 9, one or more membrane pumps 110, here two membrane pumps 110, are disposed on a mobile vehicle device, for example an over the road trailer 140 supported on tires 142 and a selectively deployable front stand 144. The trailer 140 includes a front kingpin plate 146 for connection of the trailer to a tractor truck cab (not shown). Each membrane pump 110, here two membrane pumps 110, is supported on a dedicated skid 150, shown schematically. The dirty fluid, and clean fluid, hard piping connections, for example the low pressure dirty fluid manifold 62, high pressure dirty fluid manifold 94, and associated valves 108, 109 for fluid connection of the dirty fluid into and out of the membrane pumps 110, and the clean fluid source manifold 70 and return manifold 76, and associated user selectable position valves 111, 112 for selectable supply, and venting of, clean fluid to the membrane pumps 110 are also carried on the trailer 140 and fluidly hard connected to the membrane pumps 110. Trailer hydraulic connection valves 152, for example gate or ball valves, are provided at the opposed ends of the low pressure and high pressure dirty fluid manifolds 62, 94 and the opposed ends of the clean fluid source manifold 70 and return manifold 76. Alternatively, fluid connectors or couplings may be provided at are provided at one or both of the opposed ends of the low pressure and high pressure dirty fluid manifolds 62, 94 and one or both of the opposed ends of the clean fluid source manifold 70 and return manifold 76. A controller box 162, housing the controller 158, is also mounted on the trailer 140 and selectively connected to the user positionable selection valves 111, 112 and the pump fullness detectors, such as the detector 160.

[0034] In use, one or more membrane pumps 110 may be required for a particular application requiring the high-pressure dirty fluid. For example, where more membrane pumps 110 than can be mounted on a single trailer 140 are needed, manifolds on adjacent trailers can be connected together, as appropriate, through the trailer hydraulic connection valves 152. Alternatively, the opposed ends of the low pressure and high-pressure dirty fluid manifolds 62, 94 and the opposed ends of the clean fluid source manifold 70 and return manifold 76 can be closed off with caps, or left open. In any case, one of the opposed ends of the low pressure dirty fluid manifold 62 and one of the opposed ends of the clean fluid source manifold 70 are used to connect the membrane pumps 110 to sources of dirty and clean fluid respectively, whether directly form a pump or through an appropriate manifold on another trailer, one of the opposed ends of the high pressure dirty fluid manifold 94 is connectable to a formation through a well bore, and one of the opposed ends of the return manifold 76 is connectable to a fluid storage tank. As a result of this construct, a desired pumping capacity can be deployed, used, and removed from a user site, adjacent one or more wellheads of well bores requiring a supply of high-pressure fracking fluid.

[0035] Referring to FIG. 8, an additional use of the membrane pumps 96 hereof is shown, wherein a mud pump for providing drilling mud under pressure to a wellbore is shown and described. The mud pump operates in a similar fashion to the fracking fluid delivery system of FIGS. 1 to 7, except a drilling mud composed of a liquid base, for example water, and one or more additives such as weighing agents to increase the weight per cubic foot of the liquid, as well as other agents such as clay, corrosion inhibitors salts and lubricants are mixed together before the mud is flowed to a well bore.

[0036] A mud fluid circuit 100′ utilizing membrane pumps 110 to pressurize a drilling mud is shown in FIG. 8. During operation of the fluid circuit to pressurize the mud for delivery to a borehole having a drill string selectively disposed therein to drill the borehole deeper into the earth, the fluid circuit components are located in close proximity to a drilling rig 204 located over the borehole being drilled. Here, a mud delivery unit 206 is located at the opening of the borehole into the earth, to allow drilling mud to be pumped into the borehole. The drilling mud may be delivered at ambient atmospheric pressure, or at a pressure greater than atmospheric where the opening of the borehole into the earth can be isolated from the ambient atmospheric pressure at the borehole opening into the earth location. In this case, a higher pressure than the pressure created by the weight of the drilling mud in the borehole can be experienced or imposed at the bottom, or cutting face, of the borehole. The mud delivery unit 206 is connected to a piping connected to a drilling mud ball or gate valve 103′. The drilling mud ball or gate valve 103′ isolates flow into or out of the borehole and flowing through the mud delivery unit 206. In FIG. 8, three mud delivery units 206 are shown connected to the fluid circuit 100, each through a drilling mud ball or gate valve 103′ associated with, and dedicated to, a different one of the mud delivery units 206. A fluid flow line 90 from each of the one or more drilling mud ball or gate valve(s) 103′ leads to a common flow line or manifold 92 attached to a first mud pressure relief valve 105′. The mud pressure relief valve 105′ allows emergency pressure relief to occur during an upset or other deleterious event during a drilling operation. The mud pressure relief valve 105′ is positioned between the manifold 92 leading to the one or more mud ball or gate valve(s) 103′ and a first check valve 107 leading to one or more membrane pump(s) 110 through a high pressure mud line or mud manifold 94′. The check valves in this circuit only open if there is a pressure differential between the fluid ports of the check valve sufficiently great to cause the check valves poppet or seal to move off of a seat thereof. Each of the check valves herein, unless otherwise specified, generally include a seat, a poppet which can move against the seat to seal off an opening through the seat and thus close the valve, or move away from the seat to allow fluid to pass through the opening, and a biasing element, typically a spring, which if the pressure is the same on the inlet and outlet sides of the valve, pushes the poppet against the seat to keep the valve closed and will maintain the check valve in this closed position until the pressure difference between the inlet which ports fluid to the portion of the poppet exposed within the circumference of the seat and the and the outlet is sufficient to overcome the force of the spring biasing the poppet against the seat. When the pressure on the valve inlet causes the pressure on the inlet side of the poppet to exceed the spring force, the poppet moves away from the seat and fluid can flow through the valve. If there is one and only one membrane pump in the fracking circuit, the inlet to the first check valve 107 is connected through the high-pressure mud manifold 94 to a mud outlet check valve 108′ connected to the high-pressure outlet of membrane pump 110. If there are multiple membrane pumps 110, as shown in FIG. 1 six membrane pumps, the first check valve 107 is connected through the high pressure dirty fluid manifold 94 (here carrying drilling mud) to the outlet of multiple outlet check valves 108, for example 108a-f, each membrane pump 110 having one mud outlet check valve 108 connected between the membrane pump 110 and the high pressure mud manifold 94 connected to the first check valve 107.

[0037] Each of the one or more membrane pumps 110 includes a housing providing a pressure vessel capable of securely holding in fluid at pressures of up to 15,000 or more psi, and a flexible, stretchable membrane 98 (FIG. 2, of a rubber or rubber like material) disposed therein and separating the dirty fluid volume 50 of the membrane pump 110 from the clean fluid volume 52 thereof. Each membrane pump includes a dirty fluid inlet 54, which is controlled to be open or closed by a dirty fluid inlet check valve 109 to allow a dirty fluid, here drilling mud containing the weighing agents, additives, etc., therein into the dirty fluid volume of the pump, a dirty fluid outlet 56, which is controlled to be open or closed by a dirty fluid outlet check valve 108, a clean fluid inlet 58, which is controlled to be open or closed by a clean fluid inlet user selectable position valve 111, and a clean fluid outlet 60, which is controlled to be open or closed by clean fluid outlet user selectable position valve 112.

[0038] The dirty fluid inlet check valve 109 attached to the membrane pump 110 is connected to a low pressure dirty fluid manifold 62, here containing the pre-mixed drilling mud, leading bi-directionally therefrom. In one direction the low pressure dirty fluid manifold 62 is connectable to a mud waste receptacle 114′, for example a tank trailer, and in the other direction the low pressure dirty fluid manifold 62 extends to a dirty side master check valve 115. The low pressure dirty fluid manifold 62 is here connected through the dirty side master check valve 115 to a plurality of, in this aspect, two low pressure pumps 116a and 116b. The low-pressure pumps 116a,b are each connected, on the outlet side thereof, through a mud side fluid inlet line 64′ to the inlet of the dirty side master check valve 115. They are also connected, at the inlet side thereof through appropriate piping 66 or hoses, to a water source 121 and a chemistry source 122, for example corrosion inhibitors, salts, lubricants and other mud additives. The low pressure pumps 116a, b, also include a mechanism for incorporation of the solid additives for the mud, for example granulated or powdered barite and bentonite, into the fluid, typically water, being pumped therethrough. Here, a hopper 68 is configured to receive the solid additives therein, and a screw auger, or other conveyance, intermixes the solid additives with the fluid in the pump, which is then pumped to approximately 120 psi at the outlet of the low-pressure pump 116a, b. The low pressure pump or pumps 116a,b pulls chemical additives, water, and solid additives such as weight additives from the chemistry source 122, water source 121, and solid additives source 120′a, respectively, and pressurizes the mixture to flows a low pressure mud in the direction of the dirty side master check valve 115 and in the direction of the membrane pump 110 at approximately 120 psi.

[0039] On the clean fluid side of the fluid circuit 100, one or more high pressure pumps 133 are fluidly connected, through a high pressure clean fluid source manifold 70, to the clean fluid inlets 58 of the membrane pumps 110, and the clean fluid outlets 60 of the membrane pumps 110 are connected to a return manifold 76 to return the fluid back to a fluid reservoir, such as a water tank 134. The clean fluid inlet 58 to each membrane pump 110 is controlled to be open or closed by a clean fluid inlet user selectable position valve 111. A clean fluid inlet line 72 extends from the clean fluid inlet user selectable position valve 111 toward and to a clean fluid source manifold 70. The clean fluid inlet user selectable position valve 111 is controlled by a computer to be opened or closed based upon the output of a pressure transducer or volume detector of the membrane pump 110. The clean fluid source manifold 70 extends from the connection thereof to the clean fluid inlet lines 72 associated with each membrane pump 110, to one or a plurality of on/off valves 130. The on/off valves 130 are each connected via appropriate piping to a high-pressure check valve 131. Each high-pressure check valve 131 is fluidly located between the on/off valve 130 and a pressure regulator 132. The pressure regulator 132 sets the maximum pressure that goes into the fluid lines leading to the membrane pumps 110. If a high-pressure pump overshoots the maximum desired pressure, the regulator reduces the pressure at the outlet thereof to bring the fluid pressure reaching the membrane pumps 110 within the desired pressure range.

[0040] The fluid piping for the high pressure clean fluid connects each pressure regulator 132 to a high pressure pump 133, which are each capable of compressing fluid received from the connected plurality of water tanks 134 to 15,000 psi. A series of connection lines 145 allow water to be pulled from any tank of the plurality of water tanks 134 by any of the high-pressure pumps 133.

[0041] The clean fluid outlet user position selectable valve 112 is located on the clean fluid outlet 60 and between the outlet and the return manifold 76. The clean fluid outlet user selectable position valve 112 is controlled by a computer in response to a pressure transducer or volume reader inside of the membrane pump 110. The return manifold connects to the clean fluid outlets 60 of the several membrane pumps 110 to a heat exchanger and water filter unit 136, from which a chilled water line 78 extends to return the clean fluid to the water tanks 134. The heat exchanger and water filter unit 136 cools the returning water.

[0042] The membrane pump 110 pressurizes the mud to enter the injection unit 101 and borehole at up to approximately 15,000 psi. To allow high-pressure fluid at around 15000 psi to be present in the borehole the mud flows toward the dirty side master check valve 115 in the direction of the membrane pump 110 at 120 psi, to which pressure it has been compressed by the low-pressure pump or pumps 116. By proper cycling of the clean fluid and the dirty fluid, the volume of dirty fluid, i.e., mud, present in the membrane pump can be pumped toward the well bore in a continuous flow until the volume of mud in the membrane pump is exhausted therefrom. In each fill and drain cycle of the clean fluid side of each membrane pump 110, a discrete volume of mud is pressurized to a pressure greater than that of the mud in the mud manifold 94′, and thence pushed out of the dirty side of the membrane pump and through the mud outlet check valve 108′ into the mud manifold 94′. Thus, if the borehole is sealed to allow pressurization thereof using high-pressure mud, this pushing of the mud into the mud manifold results in an increase in mud pressure in the borehole. Additionally, as the borehole is being drilled, the membrane pumps pump the mud into the borehole to increase the quantity of the mud therein in relation to the increasing volume thereof. Thus, the membrane pumping system for pumping a fracking fluid is likewise useable to mix, and pump, drilling mud, to one or more boreholes being drilled.