Method for boosting hydrocarbon production

Abstract

An apparatus and method that uses the local raw water injection equipment to use the minimally processed seawater as the hydraulic power fluid for the downhole turbine/pump arrangement. In one embodiment, the raw water provides the hydraulic power to the downhole equipment via the production well annulus in an open loop arrangement. The raw water is co-mingled with the production fluids. In another embodiment, the raw water provides the hydraulic power to the downhole equipment via the production well annulus in a closed loop arrangement. The raw water is not co-mingled with the production fluids. In another embodiment, the raw water provides hydraulic power to the downhole equipment via the production well annulus in an open loop downhole arrangement. The raw water discharged from the turbine is conveyed to a suitable formation for injection via a dual completion well.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention is generally related to the production of oil and more particularly to the injection of water into an oil bearing formation.

[0003] 2. General Background

[0004] In the production of oil, it is often necessary to boost the pressure of the produced fluids in order to achieve the required production rates. Current downhole pressure boosting methods include the injection of water into the formation, well bore gas lift, electrical submersible pumps, and hydraulically driven, downhole turbine/pump arrangements.

SUMMARY OF THE INVENTION

[0005] What is provided is an apparatus and method which uses locally generated, minimally treated sea water (raw water) injection equipment to provide the hydraulic power fluid for a downhole turbine/pump arrangement. In one embodiment, the raw water provides the hydraulic power to the downhole equipment via the production well annulus in an open loop arrangement. The raw water is co-mingled with the production fluids. In another embodiment, the raw water provides the hydraulic power to the downhole equipment via the production well annulus in a closed loop arrangement. The raw water is not co-mingled with the production fluids. In another embodiment, the raw water provides hydraulic power to the downhole equipment via the production well annulus in an open loop downhole arrangement. The raw water discharged from the turbine is conveyed to a suitable formation for injection via a dual completion well.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] For a further understanding of the nature and objects of the present invention reference should be made to the following description, taken in conjunction with the accompanying drawings in which like parts are given like reference numerals, and wherein:

[0007] FIG. 1 is a schematic illustration of the preferred embodiment of the invention.

[0008] FIG. 2 is a longitudinal cross section at the mid-plane of the hydraulic submersible pump used in the preferred embodiment of FIG. 1.

[0009] FIG. 3 is a schematic illustration of an alternate embodiment of the invention.

[0010] FIG. 4 is a longitudinal cross section at the mid-plane of the hydraulic submersible pump used in the alternate embodiment of FIG. 3.

[0011] FIG. 5 is a schematic illustration of a second alternate embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0012] FIG. 1 schematically illustrates the preferred embodiment of the invention. The existing raw water processing and injection system 12 is used to process sea water and provide the processed water for injection into the oil bearing formation below the sea floor via piping 14 in fluid communication with the wellheads 15 and the water injection wells 16. The wellheads 15 are located at the sea floor 17. The processed sea water is also used to provide the motive hydraulic power to the downhole equipment 18 via piping 20 in fluid communication with the wellheads 21 and the production well annulus 22. The production wells are indicated by numeral 19. The raw water power fluid is co-mingled with the production fluids and transported to a receiving/processing facility not shown via piping 24. The piping 24 may be above or below the water surface.

[0013] As seen in FIG. 2, the wellhead 15 includes a power fluid isolation valve 28, and a production master valve 30. Tubing hanger 32 supports production tubing 34. Casing hanger 36 supports casing 38. The production tubing 34 is preferably equipped with ported landing nipples 40 that enable the hydraulic submersible pump assembly 42 to be installed by wireline, landed, and locked in position. A sealing packer 44 positioned between the lower end of the tubing assembly 34 and the casing 38 directs the flow of production fluids into the pump assembly and isolates the power fluid. A safety valve 46 is provided at the lower end of the pump assembly 42. The safety valve 46 is controlled from the surface for shutting off the flow of production fluids if necessary.

[0014] In operation, power fluid, locally generated and processed sea water, from the processing system 12 is directed through the power fluid valve 28 into the annulus between the tubing 34 and casing 38. The power fluid enters the pump assembly at the flow crossover 48. Downhole pump assemblies are generally known but the operation will be briefly described for the sake of clarity. The power fluid flows through the pump assembly 42 to the turbine and causes the turbine and pump to spin. The pump provides power to help pull the production fluids from the formation. The production fluids exit the pump assembly at the pump discharge outlets 52 where they are co-mingled with the power fluid. The power fluid exits the pump assembly at the turbine exhaust ports 50 into the annulus between the pump assembly and production tubing. The co-mingled production fluid and power fluid flows back into the pump assembly below the flow crossover 48. The co-mingled fluids exit the pump assembly into the production tubing 34 and flow up the tubing to the production master valve 30 and into the piping 24 seen in FIG. 1. As indicated above, the piping 24 delivers the co-mingled production and power fluids to a receiving/processing facility not shown.

[0015] FIG. 3 schematically illustrates an alternate embodiment of the invention. In this embodiment, the raw water power fluid is not co-mingled with the production fluid but instead is exhausted via piping 54 to the raw water processing and injection system 12 for reprocessing and injection into the reservoir.

[0016] As seen in FIG. 4, there are several differences from the embodiment of FIG. 2. A second, smaller diameter casing 56 is provided in the annulus between the first casing 38 and the production tubing 34. This defines an annulus between the production tubing 34 and the second casing 56 and an annulus between the first casing 38 and the second casing 56. The power fluid isolation valve 28 is in fluid communication with the annulus between the production tubing 34 and the second casing 56. The wellhead includes a turbine exhaust valve 58 which is in fluid communication with the annulus between the first casing 38 and the second casing 56. The second casing 56 is provided with seals 60 that seal against the production tubing 34 and direct the crossover of power fluid to the production tubing annulus and into the pump assembly 42. The turbine exhaust 50 directs the power fluid into the annulus between the casing 38 and the second inner casing 56.

[0017] In operation, power fluid (processed sea water) from the processing system 12 is directed through the power fluid valve 28 into the annulus between the tubing 34 and second casing 56. The power fluid enters the pump assembly at the flow crossover 48. Downhole pump assemblies are generally known but the operation will be briefly described for the sake of clarity. The power fluid flows through the pump assembly 42 to the turbine and causes the turbine and pump to spin. The pump provides power to help pull the production fluids from the formation. The production fluids exit the pump assembly at the pump discharge outlets 52 into the annulus between the production tubing 34 and the second casing 56. The production fluids then reenter the pump assembly before the crossover 48 and then exit the pump assembly into the production tubing 34. The production fluids flow up through the production tubing 34 and through the master production valve to the piping 24 seen in FIG. 3. As indicated above, the piping 24 delivers the production fluids to a receiving/processing facility not shown. The power fluid exits the turbine exhaust 50 into the annulus between the first and second casings 38 and 56 and flows to the turbine exhaust valve 58. The power fluid is then directed via piping 54 to the raw water processing and injection system where it is reprocessed and injected into the reservoir.

[0018] FIG. 5 schematically illustrates an alternate embodiment of the invention. In this embodiment, the raw water power fluid is not co-mingled with the production but instead is directed to a suitable formation for injection via a dual completion well 62.

[0019] The main operation is the same as that described for FIG. 3 and 4. The difference is that the power fluid from turbine exhaust valve 58 is directed to water injection line 64 for injection into the oil bearing formation.

[0020] Because many varying and differing embodiments may be made within the scope of the inventive concept herein taught and because many modifications may be made in the embodiment herein detailed in accordance with the descriptive requirement of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.

Claims

1. A method for boosting production of hydrocarbons from a well in an oil bearing formation, comprising the steps of:

a. placing a hydraulic submersible pump in the well;

b. driving the hydraulic pump with locally generated and processed sea water; and

c. directing the water exhaust from the hydraulic pump into a common line with the produced hydrocarbons.

2. A method for boosting production of hydrocarbons from a well in an oil bearing formation, comprising the steps of:

a. placing a hydraulic submersible pump in the well;

b. driving the hydraulic pump with locally generated and processed sea water; and

c. directing the water exhaust from the hydraulic pump into a separate line from the hydrocarbons for reuse.

3. A method for boosting production of hydrocarbons from a well in an oil bearing formation, comprising the steps of:

a. placing a hydraulic submersible pump in the well;

b. driving the hydraulic pump with locally generated and processed water;

c. directing the water exhaust from the hydraulic pump into a separate line from the produced hydrocarbons; and

d. injecting the water exhaust from the hydraulic pump into the oil bearing formation.