Method and device for producing fluids or gases from a horizontal well

Abstract

The present invention relates to a method for producing fluids or gases from a horizontal well 10, the method comprising the steps providing a horizontal well 10 having a horizontal production openhole 20, dividing the horizontal production openhole 20 into at least two separate compartments 30, 32 by means of blockers 40, 42, providing for each separate compartment 30, 32 at least one production string 50, 52, and passing fluid or gas 100, 102 from each compartment 30, 32 to the surface 106 via the corresponding production strings 50, 52. The present invention further relates to a fluid or gas production device 1 for horizontal fluid or gas wells.

Claims

1. A method for producing fluids or gases from a horizontal well, the method comprising the steps: (a) providing a horizontal well having a horizontal production openhole; (b) dividing the horizontal production openhole into at least two separate compartments, by means of blockers; (c) providing for each separate compartment at least one production string; (d) passing fluid or gas from each compartment to the surface (106) via the corresponding production strings; and (e) controlling a production flow rate of liquid or gas of each compartment individually, the controlling step including adjusting the flow rate according to an estimated volume of fluid or gas in a formation, or formations, adjacent to the respective compartment such that water coning is managed or avoided.

2. The method according to claim 1, wherein the step of controlling the production flow rate of each individual production string includes a simultaneous, or non-simultaneous, passing of fluid or gas from all compartments to the surface.

3. The method according to claim 1, further comprising the step of injecting an injection liquid, or gas, simultaneously, or non-simultaneously, into all compartments or into one compartment after the other according to a certain timely pattern, via corresponding injection strings of each compartment.

4. The method according to claim 1, further comprising the steps of: inserting a metal tube into the horizontal well for providing an outer shell of the openhole; cementing an area around the metal tube; and providing a porous structure in the metal tube, preferably by igniting an explosive charge inside the openhole of the horizontal well.

5. The method according to claim 1, wherein said step of controlling the production flow rate of fluid or gas of each compartment individually is done by means of: at least one flow control device of at least one of the compartments; and/or at least one flow control device of at least one of the strings; and/or at least one sensor of at least one of the strings; and/or a downhole processor of at least one of the strings; and/or a communication capability of at least one of the strings, for communicating with a remote location.

6. A fluid or gas production device for horizontal fluid or gas wells, comprising: a horizontal well having a production openhole; at least one blocker inside the production openhole for dividing the production openhole into individual compartments; and at least two individual production strings, of which at least one extending inside the production openhole, from the surface to one of the compartments with at least one production string individually for each compartment; wherein each individual production string is connected to a choke, for individually controlling a production flow rate of fluid or gas for each compartment; and wherein each of the production strings includes at least one flow control device which adjusts the flow rate according to an estimated volume of fluid or gas in a formation, or formations, adjacent to the respective compartment such that water coning is managed or avoided.

7. The production device according to claim 6, wherein each blocker is impermeable for the fluid or gas and can be positioned freely along the length of the production openhole or casing.

8. The production device according to claim 7, wherein the individual production strings extend through the respective blocker or blockers and the respective blocker seals the pass of each production string against the fluid or gas.

9. The production device according to claim 6, wherein each individual production string can also be used as an injection string for injecting an injection liquid or gas from the surface to the corresponding compartment.

10. The production device according to claim 6, wherein the production openhole further comprises a permeable outer shell to allow the fluid or gas to penetrate from a formation, or formations, into the production openhole, wherein the outer shell is made of a metal tube and a cement layer, which have a porous structure.

11. The production device according to claim 6, wherein the production strings are made of a flexible and durable material, allowing to be bent from the vertical well to the horizontal production openhole and to endure high pressures of the fluid, gas and/or injection liquid, gas piped through.

12. The production device according to claim 6, wherein said compartments include at least one flow control device.

13. The production device according to claim 6, wherein said string includes at least one sensor.

14. The production device according to claim 6, wherein said string includes a downhole processor.

15. The production device according to claim 6, wherein said string includes a communication device for communicating with a remote location.

Description

4. BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, preferred embodiments of the invention are disclosed by reference to the accompanying figures, in which shows:

(2) FIG. 1: a schematic cross-sectional view of a fluid or gas production device according to an embodiment of the present invention;

(3) FIG. 2: a schematic cross-sectional view of an embodiment of the horizontal production well according to the present invention;

(4) FIG. 3: a schematic cross-sectional view of a fluid or gas production device according to another embodiment of the present invention; and

(5) FIG. 4: a schematic cross-sectional view of a fluid or gas production device according to another embodiment of the present invention.

5. DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

(6) In the following, preferred embodiments of the invention are described in detail with respect to the figures.

(7) FIG. 1 shows a schematic cross-sectional view of a fluid or gas production device 1 according to an embodiment of the present invention. Thereby, the region denoted by reference sign 106 represents the earth's surface and the region below surface 106 including formation, or formations, 104 is a subsurface region. This subsurface region comprises several different layers of formation (not explicitly shown), mainly extending in a horizontal direction, like oil or gas containing formation 104 in FIG. 1. Thus, formation 104 contains oil or gas 100, 102. In general, the oil or gas 100, 102 is available in the form of small droplets directly embedded in the structure of formation 104. Moreover, formation 104 may have a rather small vertical extension but a wide horizontal extension. Due to this, oil or gas 100, 102 production by means of a common vertical well 18 is less economical here and hence a horizontal well 10 is used in formation 104. It is to be noted that also more than one formation 104 may occur at an oil or gas 100, 102 production site. Different formation 104 layers containing oil or gas 100, 102 may be present at different depths.

(8) Furthermore, a well is shown in FIG. 1 comprising a vertical well 18 and a horizontal well 10. Thereby, the vertical well 18 is drilled down by common drilling techniques to a depth above the formation 104 layer. Then, the vertical well 18 is extended in a curved way until it becomes a horizontal well 10. The transition zone between the curved path of the well or production openhole and the horizontal production openhole 20 is called “heel” 24. The distal end of the horizontal production openhole 20 is called “toe” 26. At the toe 24, the horizontal well 10 may be open to sediment 104. The course of horizontal well 10 does not need to be strictly horizontal in a mathematical way, but may provide some uphill slopes and descents. In an ideal case, the horizontal well 10 is arranged at a horizontal center line of formation 104 following its course in a horizontal direction. This would provide a uniform distribution of the oil or gas volume in formation 104 around the horizontal production openhole 20. In practice, however, the extend of formation 104 around the horizontal production openhole 20 differs along the length of the openhole leading to different distributions of oil or gas 100, 102.

(9) In general, the diameter of the well 10, 18 is between 100 mm to 800 mm. The diameter of each production string 50, 52 is significantly smaller than the diameter of the production hole 20 such that one or multiple production strings 50, 52 can be inserted or arranged into one production openhole 20. Because FIG. 1 is a schematic drawing only, not all possible production strings are shown and only two production strings are shown extending to surface 106. In practice, however, every production string will extend from the horizontal production openhole 20 to surface 106 for individual oil or gas recovery. Each production string 50, 52 ends in one of the compartments 30, 32 and comprises an open end such that oil or gas 100, 102 discharged from formation 104 can enter a production string 50, 52 and flow to the surface. Thereby, the volume of oil or gas 100, 102 flowing through a production string 50, 52 can be given by the production flow rate 54, 56 that can be measured by commonly known measurement instruments on the surface 106, e.g. at chokes 60, 62. For the control of the production flow rate 54, the compartments may include at least one flow control device. Further, the production strings 50, 52 may include at least one flow control device. For example for measuring the flow rate, pressure or temperature of the oil or gas the strings 50, 52 may include a corresponding sensor (not shown). Furthermore, preferably, the strings 50, 52 may include a downhole processor 70, 72 and preferably the strings 50, 52 include a communication capability for communicating with a remote location, preferably at surface level. The controlling of the production flow rate 54, 56 can be performed by means of the mentioned chokes 60, 62, wherein each choke is connected to exactly one production string. The chokes 60, 62 are preferably arranged at the surface 106. For controlling purposes the operation of multiple or all chokes may be controlled by one choke controlling unit (not shown). Furthermore, it is possible to control the production flow rates 54, 56 by means of a pump or valve (not shown) or any appropriate means for controlling a fluid or gas flow in a pipeline. Thereby, the intake pressure of a production string 50, 52 can be generated by means of a pump or arises from the pressure of the oil or gas 100, 102 discharging from formation 104. The application of fracking techniques might increase the fluid or gas pressure in formation 104.

(10) The produced oil or gas 100, 102 passing the choke 60, 62 of the respective production string 50, 52 is then passed via a pipeline to further production units for further processing (not shown).

(11) FIG. 2 shows a schematic cross-sectional view of an embodiment of the horizontal production openhole 20 according to the present invention. Thereby, the horizontal production openhole 20 is positioned in formation 104 containing oil and/or gas 100, 102. The toe region is depicted on the right-hand side in FIG. 2 and the heel region is at the left hand side of FIG. 2, where the curved path of the production openhole connecting the vertical well 18 (upwards) and the horizontal well 10 is shown.

(12) The outer circumference of the horizontal production openhole 20 may comprise a metal tube 12 and optionally a cement layer in an area 14 between the metal tube 12 and formation 104. Thereby, the metal tube 12 and the optional cement area 14 comprise a porous structure 16, i.e. they comprise fractures or small holes that enable oil or gas 100, 102 to penetrate into the horizontal production openhole 20. Thereby, metal tube 12 may already comprise such small holes or get these holes because of an intended explosion inside the horizontal production openhole 20. Furthermore, this explosion will generate small cracks or fractures in the optional cement area 14 such that it gets a porous structure 16 as well. The porous outer shell 22, comprising the perforated metal tube 12 and optionally the porous cement area 14, will prevent larger formation 104 particles from getting into the horizontal production openhole 20. The tubing may be initially slotted, e.g. a slotted liner, with no need for cementing or perforation.

(13) Furthermore, the horizontal production openhole 20 is divided into compartments 30, 32 by means of fluid and/or gas impermeable blockers 40, 42. Along the horizontal production openhole 20 an arbitrary number of blockers 40, 42 can be arranged at equal or non-equal distances to each other. The positioning of the blockers 40, 42 may be performed for example according to formation 104 characteristics of the oil/gas 100, 102 volume in a region. These blockers 40, 42 also provide support for the production strings 50, 52 passing therethrough. The blockers are swellable and are made of an elastic material such that they seal each compartment in the fully swollen state at their outer circumference. Thus, they can be inserted into the production openhole easily in a dry state wherein they are smaller than the diameter of the openhole, and can be positioned simply by getting wet. Furthermore, due to their flexible mechanical properties they also seal the production strings 50, 52 extending therethrough.

(14) Because of a lower pressure inside the horizontal production openhole 20 oil or gas 100 discharges from formation 104 into the production openhole 20 at compartment 30. Oil or gas 102 enters into compartment 32. Thereby, the lower pressure in production openhole 20 may be generated by a pump, preferably positioned at surface 106 or below surface, or due to a higher pressure on the oil or gas 100, 102 in formation 104 compared to the pressure in each compartment 30, 32 of horizontal production openhole 20. The oil or gas 100, 102 pressure in formation 104 may be increased by an application of fracking techniques. A higher oil or gas 100, 102 pressure may lead to higher production flow rates 54, 56 and may, thus, increase overall production efficiency.

(15) All in all, a permanent discharge of oil or gas 100, 102 from formation 104 into horizontal production openhole 20 is possible. The production flow rate for each compartment 30, 32 can be individually controlled by corresponding individual chokes 60, 62 for each individual production string 50, 52. Of course, the production flow rate 54, 56 in one compartment 30, 32 can be decreased to zero, if needed, for example if water enters this compartment. Further, the production may be started or increased again at a later point in time by simply opening the choke 60, 62 again.

(16) By individually controlling the production flow rate 54, 56 of each compartment 30, 32 an essentially even distributed oil or gas 100, 102 volume in formation 104 around the horizontal production openhole 20 can be achieved. Because of this even distribution of oil or gas 100, 102, no or delayed water coning occurs. Thus, in practice a large volume of oil or gas 100, 102 in formation 104 can be discharged into horizontal production openhole 20 before a significant amount of water will penetrate into the openhole 20 and the well has to be abandoned. This increases the productivity of a horizontal well significantly.

(17) FIG. 3 shows a schematic cross-sectional view of a fluid or gas production device 1 according to another embodiment of the present invention. Therein, a first compartment 30 is formed in the production openhole 20 between a first blocker 40 and a second blocker 42. Each blocker may comprise multiple sections that further may be spaced apart to each other as can be seen for example at blocker 42. A second compartment 32 is formed between the toe 26 of the horizontal production openhole 20 and blocker 42. Oil or gas 100, 102 discharging from formation 104 can penetrate the horizontal production openhole 20 along the dotted line in FIG. 1. The oil or gas 100, 102 in each of the first or second compartment 30, 32 will then pass through the respective first or second production string 50, 52 to the surface. As can be seen in FIG. 3 the first production string 50 can also be arranged in the vertical well 18, however, nevertheless it will only get oil or gas 100, 102 from formation 104 in the horizontal production openhole 20. In conclusion, also with this embodiment of the present invention oil or gas 100, 102 can be produced simultaneously, or non-simultaneously, from both compartments 30, 32 in the horizontal production openhole 20. The long string 52 can be divided into multiple sections, preferably two or more sections. In FIG. 3, it is divided into two sections, a lower and an upper section. The lower section in this figure is equipped with a perforated joint to allow for gas or oil 100 to be produced from string 50.

(18) FIG. 4 shows a schematic cross-sectional view of a fluid or gas production device 1 according to another embodiment of the present invention. Therein, a first compartment 30 is formed in the production openhole 20 between a first blocker 40 and a second blocker 42. Each blocker may comprise multiple sections that further may be spaced apart to each other. A second compartment 32 is formed between the toe 26 of the horizontal production openhole 20 and blocker 42. Oil or gas 100, 102 discharging from formation 104 can penetrate the horizontal production openhole 20 along the dotted line in FIG. 4. The oil or gas 100, 102 in each of the first or second compartment 30, 32 will then pass through the respective first or second production string 50, 52 to the surface. As can be seen in FIG. 4 the first production string 50 can also be arranged in the vertical well 18, however, nevertheless it will only get oil or gas 100, 102 from formation 104 in the horizontal production openhole 20. In conclusion, also with this embodiment of the present invention oil or gas 100, 102 can be produced simultaneously, or non-simultaneously, from both compartments 30, 32 in the horizontal production openhole 20.

LIST OF REFERENCE SIGNS

(19) 1 fluid or gas production device 10 horizontal well 12 metal tube 14 area around metal tube 12 16 porous structure 18 vertical well 20 production openhole 22 outer shell 24 heel 26 toe 30 first compartment 32 second compartment 40 first blocker 42 second blocker 50 first injection/production string 52 second injection/production string 54 first production flow rate 56 second production flow rate 60 first choke 62 second choke 100 oil/gas of compartment 30 102 oil/gas of compartment 32 104 formation 106 surface