Abstract
The gas lift accelerator is a method and a downhole apparatus based on the principle of the jet pump to allow the extraction of reservoir fluids up to high API grade with low or no reservoir pressure, at any depth, by injecting available gas in the oil field, allowing the flexibility of operation on diverse well completion configurations like sliding sleeve type and gas lift mandrels, complementing the operating when other methods like traditional gas lift procedures or hydraulic fluid jet pumps are not effective. The gas lift method includes the use of downhole and surface metering data to optimize the operation of the gas lift accelerator apparatus.
Claims
1. A downhole gas lift accelerator apparatus for oil extraction in a well comprising a jet pump module including a tubular mandrel housing which contains an internal Venturi throat and a Venturi diffuser and a Venturi nozzle, connecting a bottom side low pressure well fluid with an upper side energized mixture on the inside of a production conduit, an inlet conduit connecting an annular space between an outside surface of the mandrel housing and a well case with the internal Venturi throat, to provide flow of a pressurized gas injected from a surface device through the annular space between the well case and an annular production tube, such gas being accelerated as it passes through the inlet conduit and the Venturi nozzle into the Venturi throat, thereby forming a pressure drop that produces a low pressure, high density well fluid located at the bottom of the jet pump to flow towards the Venturi throat such that an accelerated gas mixes with the well fluid to form the energized mixture at the Venturi diffuser, a back flow restraint element that can move between a closed or an open position at an inlet gas pressure threshold, at least one exchangeable interface element which attaches the jet pump module to the production tube and seals the passage for fluids between an apparatus inner side and an outer side, being located at the upper side of the jet pump module or at the lower side of the jet pump module or in both sides of the jet pump module relative to the production of the well.
2. The apparatus of claim 1 where the jet pump module with the inlet conduit and the back flow restraint element can be used in oil wells with different completion configuration by only replacing at least one of the exchangeable interface elements.
3. The apparatus of claim 2 where the exchangeable interface elements includes a fish neck retrieval sub to operate in wells with an installed gas lift mandrel on the production tube.
4. The apparatus of claim 2 wherein the exchangeable interface elements includes a tubing anchor lock to operate in a well with an installed sliding sleeve on the production tube.
5. The apparatus of claim 1 wherein the injected gas is accelerated to supersonic level when passing through the Venturi nozzle into the Venturi throat comprising a constrictor.
6. The apparatus of claim 1 wherein the inlet conduit, the Venturi throat, the Venturi diffuser and the Venturi nozzle of the jet pump module are made of carbon steel 4140 with tungsten.
7. The apparatus of claim 1 wherein the back flow restraint element can comprise a blocking element and a bias spring that can be adjusted according to the depth of operation, type of oil in the well and pressure of the oil.
8. The apparatus of claim 7 wherein the back flow restraint element is adjusted by variation of the spring element.
9. The apparatus of claim 1 wherein the back flow restraint element can be used as a gas lift control valve.
10. The apparatus of claim 1 wherein the well fluid flows up to the surface by the combined effect of the pressure increase of the gas/oil mixture, the lower density of the energized mixture respect to the oil itself and the pressure drop at the Venturi throat.
11. The apparatus of claim 1 further comprising a lower nipple containing pressure sensors, temperature sensors, and data transmitting elements attached to the lower side of the jet pump module.
12. The apparatus of claim 11 further comprising a surface data acquisition and processing unit receiving the data from the downhole sensors.
13. A method for extracting oil in a well by injecting gas from a surface device into a down hole gas lift accelerator apparatus comprising a jet pump module, an inlet conduit with a back flow restraint with a spring type element, a lower module with pressure and temperature sensor, a surface data processing equipment and supplementary oil operation device including a surface gas pressure station and a well service running tool, the method comprising the steps, setting the downhole gas lift accelerator apparatus to one or more well conditions before delivery into a well bore; verifying location of a downhole packer at a specified production depths; lowering the downhole gas lift accelerator apparatus into the well down to the operating depth with the well service running tool and device; locking the downhole gas lift accelerator apparatus to the production tubing or an element installed previously to the completed production tubing at the operating depth; injecting the high pressure gas from the surface gas pumping station through the annular between the casing and the production conduit until reaching the operational pressure level over the opening of the back flow restrain element; processing the data acquired from the well fluids with the downhole sensors and measurements on surface recovered mixture; pumping the well fluids up to the surface; and evaluating system performance and adjusting the gas pressure and flow.
14. The method according to claim 13 wherein the settings of the downhole gas lift accelerator apparatus comprises the replacement of the exchangeable interface element according to the type of completion of the well.
15. The method according to claim 13 wherein the settings of the downhole pumping apparatus comprises modifications to the spring element of the back fluid restrain to adjust it to the required pressure.
16. The method according to claim 13 wherein such service running tool and device can be a wire line equipment.
17. The method according to claim 13 wherein such service running tool and device can be a slickline system.
18. The method according to claim 13 wherein such service running tool and device can be a coil tubing system.
19. The method according to claim 13 wherein such service running tool can be a GS and GO style running tool.
20. The method according to claim 13 wherein the locking of the downhole gas lift accelerator apparatus to the production tubing may require successive trips of the service running tool to lock sequentially the interface elements of the apparatus to the production tubing or the completion elements of the well.
21. The method according to claim 13 wherein the operating depth can be greater than 10.000 feet.
22. The method according to claim 13 wherein the inlet conduit of the gas lift apparatus must be above the depth of the downhole packers.
23. The method according to claim 13 wherein the oil to be extracted is a heavy crude oil with API grade over 10.
24. The method according to claim 13 wherein the reservoir fluid to be extracted has no pressure to overcome the hydrostatic column to flow up to the surface.
25. A method to control the distribution of a gas into one or more oil producing wells with a gas lift accelerator apparatus comprising a jet pump module, an inlet conduit with a back flow restraint, a lower module with a pressure sensor and a temperature sensor, a data processing device and a surface gas pressure station, the method comprising the steps of: evaluating well conditions to determine a gas pressure and flow rate for the one or more oil producing wells; injecting pressurized gas at a preliminary pressure and flow level; measuring pressure and temperature data in at least one well; processing the data; performing computational analysis of the processed data; and correcting parameters of the gas pressure and flow rate.
26. The method of claim 25 wherein the surface gas pressure station comprises a pump that receives control signals from the data processing device.
27. The method of claim 25 further comprising controlling a temperature of the gas being injected into the at least one well.
28. The method of claim 25 further comprising accelerating fluid through a Venturi in the jet pump module.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0038] FIG. 1a is a schematic section view of a producing oil/gas well with a gas lift accelerator tool installed, during operation.
[0039] FIG. 1b illustrates the Venturi effect having a constriction or choke in a reduced diameter region of the tube.
[0040] FIG. 1c illustrates the functional relationship for vertical lift performance and inflow performance and optimal sensor measurement positions in the well.
[0041] FIG. 2a is a partial view of a longitudinal cross section of an embodiment of the gas lift accelerator tool installed on a producing oil/gas well during operation, showing arrow for the power fluid, reservoir fluid and mixture pumped to surface
[0042] FIG. 2b is a detailed view of a section from FIG. 2a showing an exemplary embodiment of the gas lift accelerator assembly indicating the fluid flows during operation.
[0043] FIG. 3 is a longitudinal cross section through an exemplary embodiment of a tool equipped with a lock mandrel for installation into wells equipped with landing nipples when not installed in well.
[0044] FIG. 4 is a longitudinal cross section through an exemplary embodiment of a tool equipped with internal fishneck retrieval sub and top and bottom anchor locks for installation into wells equipped with gas pocket mandrels when not installed in a well.
[0045] FIG. 5 is a longitudinal cross section through the tool shown in FIG. 3 equipped with lock mandrel for installation into wells equipped with landing nipples, installed in well during operation.
[0046] FIG. 6 is a longitudinal cross section through the tool shown in FIG. 4 equipped with internal fishneck retrieval sub and top and bottom anchor locks for installation into wells equipped with gas pocket mandrels, installed in well during operation.
[0047] FIG. 7a to FIG. 7d is a sequence of an exemplary embodiment of a method of installation of the gas lift accelerator assembly configured for wells with gas pocket mandrels shown in FIG. 4 using a GO and GS style running tool.
[0048] FIG. 8a is a detailed longitudinal section view of an embodiment of a back flow restraining element of the gas lift accelerator tool showing the restraining element in open position allowing the flow of the power fluid injected into the gas lift accelerator tool.
[0049] FIG. 8b is a detailed longitudinal section view of an embodiment of the back flow restraining element of the gas lift accelerator tool showing the restraining element in normally closed position preventing the flow of the reservoir fluid into the annular
[0050] FIG. 9 is a schematic sectional view of a plurality of wells with gas lift accelerator assemblies installed into each of them, with reservoir fluid sensors located in a sensors nipple at the bottom of the GLA assembly.
[0051] FIG. 10a is a flow chart illustrating an exemplary embodiment of a method for operating an oil/gas well.
[0052] FIG. 10b is a flow chart depicting the processing and control of a plurality of wells.
DETAILED DESCRIPTION
[0053] FIG. 1a is a schematic representation of the gas lift accelerator device (1) installed down hole in oil/gas wells, above a producing reservoir isolated with the packer (33) receiving pressurized gas (20) pumped from the surface compressors (41) through the annular space formed between the well casing (31) and the production tubing (32). The pressurized gas passes though the Venturi jet pump in (1) and mixes with the low pressure formation fluid (21) inside the production tubing, allowing the gas-formation fluid mixture (22) to flow up to the surface, where a separation device (42) can separate the gas from the pumped mixture.
[0054] FIG. 1b illustrates the Venturi effect where A.sub.1 is the cross-sectional area of flow below the narrow passage of the Venturi throat with corresponding velocity v.sub.1 and pressure p.sub.1 values, A.sub.2 showing the cross-sectional area within the constriction that can be indicated by the change in height h, and finally the increased velocity v.sub.2 and pressure value p.sub.2 above the constriction.
[0055] FIG. 1c shows an exemplary functional relationship for the IPR and VLP described herein
[0056] FIG. 2a shows a partial view of a longitudinal section view of an embodiment of the present gas lift accelerator device installed on a producing well, where the gas lift acceleration assembly (1) is located on a general gas pocket mandrel (34) as the ones installed for traditional gas lift operations, already installed on the well for previous gas lift recovery, with the arrow (21) representing the reservoir fluid flowing to the surface direction, the arrows (20) representing the gas injected down to the gas lift acceleration device from surface equipment, such as the fluids isolated by the packer (33) already installed on the producing well.
[0057] FIG. 2b is a detailed view of a portion of FIG. 2a showing some of the gas lift accelerator assembly components including the gas inlet conduit (101) which allows the entrance of the pressurized gas (20) from the annular into the internal area of the jet pump nozzle (103) where the gas (20) is accelerated to supersonic speed producing a drop of pressure that makes the reservoir fluid (21) flow up to the Venturi throat (106) where the gas (20) and the reservoir fluid (21) create a mixture (22) in the transition zone (104), which increase its pressure at the Venturi diffuser (105) resulting in a fluid with higher pressure and lower density than the original reservoir fluid, which allows it to overcome the hydrostatic column and flow up to the well surface.
[0058] FIG. 3 is an embodiment of a gas lift accelerator assembly (1) configured for an installation into oil/gas wells where a landing nipple is installed in the production tubing. In this embodiment, the gas lift acceleration assembly (1) is assembled into a lock mandrel installation configuration (110) where a lock mandrel (111) can be installed into the landing nipple. The device is equipped with upper sealing element (112) and lower sealing elements (113). The injection fluid enters the device via inlet tube (114). The check valve (102) prevents well fluid from flowing to surface equipment when the device is operating. Replaceable Venturi jet nozzle (103) provides high velocity fluid energy to enter the Venturi. Venturi throat (104) provides a mixing area for injection and well fluids. Venturi diffuser (105) converts high velocity/low pressure fluid energy to low velocity/high pressure fluid energy. Well fluid enters the tool at the inlet sub (11).
[0059] FIG. 4 is an embodiment of a gas lift accelerator assembly (1) configured for an installation into oil/gas wells where a gas pocket mandrel for gas lift operations is installed in the production tubing. The embodiment of the gas lift acceleration assembly (1) shown in FIG. 4 is similar to the embodiment shown in FIG. 3 and is assembled into a gas pocket mandrel configuration (120) by adding an internal fishneck retrieval sub (121) an upper tubing anchor lock (122) and a lower tubing anchor lock (123) to the top and bottom sides of the device. As should be appreciated, this allows the use of the same device assembly (1) for different well completion configurations.
[0060] FIG. 5. shows an exemplary installation of the lock mandrel installation configuration assembly (110) shown in FIG. 3 into an oil well with a slotted production tubing or sliding sleeve tubing element (35), which allows the pass of the pressurized gas (20) into the gas lift acceleration device (1). The gas is contained between the casing (34) and the casing packer (33) forcing the gas (20) to flow into the tool (1). The complete assembly is fixed to the production tubing by a locating nipple (36) which attaches the lock mandrel (111) creating a conduit for the mixture fluid (22) to flow towards the surface. The tool assembly (1, 110) can be sent downhole in different ways including wire lines, inside the production tubing, and its setting depth position is precise because it is conditioned by the locating nipple (36) or other marker installed on the production tubing.
[0061] FIG. 6 shows an exemplary installation of the gas pocket installation configuration assembly (120) shown in FIG. 4 into an oil well with gas pocket mandrels (35) for gas lift recovery. The pressurized gas is constrained by the casing and the packer (33), and enters from the annular area into the gas lift accelerator through the pockets of the gas lift mandrel, with or without valves installed, to create the Venturi effect and produce the flow of the gas/oil mixture up to the surface. There are upper and lower seals (125) and (124) to seal the conduit from the suction of the tool (1) with the fluid inlet of the reservoir fluid. The tool can be precisely located by the upper tubing anchor lock (122) and the lower tubing anchor lock (123), making the pockets of the gas lift mandrel be coincident with the inlet conduit (101) shown in FIG. 2b.
[0062] FIG. 7a, 7b, 7c and FIG. 7d illustrate an exemplary embodiment of a method for precisely locating the gas pocket installation configuration assembly (120) of the gas lift accelerator into a gas lift mandrel (35) installed on a well. In FIGS. 7a to 7d, the tool is not represented in a sectional view. The tools that may be used for setting of the tool assembly (120) can be a GO style running tool (140) and a GS style running tool (141). FIG. 7a shows the setting of the lower tubing anchor lock (123), which is driven by the GO style running tool (140) down to a specified depth by any depth correlation method, to be located at a specific position inside the gas lift mandrel (35), above the packer (33). The GO style running tool (140) is retrieved to surface. The gas lift accelerator assembly (1) is driven downhole by the GS style running tool (141), and attached to the previously installed lower tubing anchor lock (123) at an specific depth inside the gas lift mandrel (35), in order to be coincident with the opening of such gas lift mandrel (35), which allows the entrance of the power fluid from the annular space formed with the casing (34) into the gas lift accelerator conduits. The GS style running tool (141) is released and retrieved. The upper tubing anchor lock (122) can be driven downhole by the GO style running tool (140) at the top of the gas lift accelerator assembly (1, 120), positioning it by any suitable depth correlation method. The upper tubing anchor lock (122) and the lower tubing anchor lock (123) may completely secure the position of the gas lift accelerator assembly (1, 120) avoiding displacement or damage during operation or from unintended impact with a downhole tool or tube put down into the well. The GO style running tool (140) is released and retrieved to surface. The depth of the installed upper tubing anchor lock (122) is verified by running a diagnostic tool, such as those used in fishing procedures like impression blocks or any other typical electronical tools. After conformity of depth, the gas lift accelerator tool is ready for operation by injecting the gas or power fluid downhole through the annular area, flowing into the gas lift accelerator inlet conduit though the aligned openings of the gas lift mandrel (35).
[0063] FIG. 8a and FIG. 8b show an exemplary embodiment for the check valve element (102) of the gas lift accelerator tool, represented by a spherical body, but not limited to other geometries used in sealing valve mechanisms, acting as a normally closed valve, with a spring like element but not limited to it, which pushes the spherical element against a settlement to avoid the passage of the reservoir fluid (21) when the pressure in the annular area between the tool and the casing (34) is lower than that of the reservoir fluid. FIG. 8a shows the case where injection fluid (20) pressure is greater than reservoir pressure and enters the device and opens the check valve to energize the Venturi. Well fluid (21) is drawn into the tool and mixes with the jet fluid in the Venturi throat. The mixed fluid (22) is then lifted to surface from the increased pressure resulting from the Venturi diffuser. FIG. 8b shows the case where pressure of injection fluid (20) is less than reservoir pressure or not present. Well fluid (21) drawn into the tool closes the check valve to block the open conduit to the surface equipment.
[0064] FIG. 9 is an schematic view of a plurality of producing oil/gas wells with a GLA bottom hole assembly (1) and a fluid sensor device or nipple (130) installed at the bottom of it, illustrating an exemplary embodiment of a gas lift accelerator method in which a common source of gas (20) or any other power fluid is pressurized and pumped downhole through the annular space formed between the casing 34 and the production tubing (37). The method can include registering the data of the pressure and temperature with the downhole sensors (131) located in the sensor nipple (130) sent by a communication element (132) and process it by surface data processing equipment, and run computational simulations and algorithms in order to establish the appropriate parameters of the pressurized gas (20) to be supplied to each well. The algorithms and simulations can allow optimization of the gas or power fluid resources used, use smaller surface compression resources and energy, which may be useful for oil fields with a large number of producing wells utilizing a gas lift accelerator recovery system, and allows dynamic adjustment of the operation of the gas lift accelerator tool according to variations on the reservoir fluid, to optimize the well production. The computer 200 can be electrically connected to the one or more sensors via wiring 204 extending into the well and processes the data to generate further control signals to the pump and other electrically actuated controls to adjust fluid pressure in the system. The computer 200 can include a display, one or more data processors, one or more memories and can be connected to a network for remote monitoring and control of the system using a remote computer 206 and data storage system.
[0065] Permeability defines the ability of a rock to allow flow through its interconnected pores. The Well core flow test is a method for determining the permeability of the formation and comparing potential damage due to the use of one or more fluids in a well. These tests are performed on a permeability test bank, which is an instrument that records flows and pressures as fluids pass through the rock cores to calculate permeability according to the Darcy's Law equation considering horizontal flow: Where the discharge q.sub.0 for a particular system can be reflected in the following equation where K.sub.0 is the permeability of the medium, P.sub.eP.sub.wfs is the pressure drop, M.sub.0 is the dynamic viscosity, and remaining terms defined by the geometry of the system (see generally M. King Hubbert (1957) Darcy's Law and the Field Equations of the Flow of Underground Fluids, Hydrological Sciences Journal, 2:1, 23-59, DOI: 10.1080/0262 6665709493062), the entire contents of which is incorporated herein by reference.
[00001]
[0066] Referring now to FIG. 10a, a flow chart illustrating an exemplary embodiment of a method 1000 for operating an oil/gas well is provided. The method 1000 includes pumping gas 1001 downhole through a plurality of oil/gas wells. In some exemplary embodiments, the gas is pumped 1001 through an annular space formed between a casing 34 and a production tubing 37 of a GLA bottom hole assembly 1. The method 1000 further includes registering data 1002 including a downhole pressure and a downhill temperature of at least one of the oil/gas wells. In some exemplary embodiments, the data can be registered with downhole sensors 131 located in a sensor nipple or marker 130 installed in the GLA bottom hole assembly 1. The registered data is processed 1003 and computational analysis of the processed data is performed 1004 to establish pressurized gas supply parameters, which may be used to determine how the gas is pumped 1001 to one or more of the oil/gas wells. Exemplary pressurized gas supply parameters may include, but are not limited to, flow rate, temperature, and pressure of the supplied gas. In some exemplary embodiments, the data may be sent from the nipple 130 to data processing equipment at the surface by, for example, a communication element 132 in the nipple 130. In some exemplary embodiments, the method 1000 is run in a continuous loop to constantly monitor and, if needed, adjust the gas supply parameters to one or more of the oil/gas wells.
[0067] FIG. 10b illustrates a process 2000 in which computer 200 and/or remote server or data processor 206 processes 2003 measured data 2002 from a plurality of wells 1 . . . N to adjust injection parameters 2004 at each of the wells 2001. The data can include pressure and temperature measured by sensors in each of the well as described herein. The system provides feedback control of the parameters of the fluid injected into the well including temperature, pressure and flow rate.
[0068] Although the teachings herein have been described with reference to exemplary embodiments and implementations thereof, the disclosed systems are not limited to such exemplary embodiments/implementations. Rather, as will be readily apparent to persons skilled in the art from the description taught herein, the disclosed systems are susceptible to modifications, alterations and enhancements without departing from the spirit or scope hereof. Accordingly, all such modifications, alterations and enhancements within the scope hereof are encompassed herein.
