The present invention relates in general to pumping systems and by example to an injection system for deployment below the surface of a water body for injecting fluid into a subterranean formation.
A secondary means of recovering hydrocarbons from an oil or gas field is to inject water into the subterranean reservoir to maintain reservoir pressure and to drive certain fractions of the hydrocarbons to producing wells. Water flooding operations require in general, a sufficient supply of water for injection; means for treating the source water to meet the reservoir conditions; a pump system; and access to the formation via a wellbore. In land based operations the source of the water is commonly from fluid produced from the subject reservoir; water treatment facilities can be readily constructed and accessed; and traditional pumping equipment is readily available. Water flooding conducted in marine operations presents drawbacks that can preclude the use of water flooding to obtain currently available hydrocarbon reserves.
Marine operations, being those in which the wellbore is below a water body and access to the wellbore is primarily via a platform or water craft, present logistical and economic limitations. In current offshore or marine water flood operations the water source is often produced well water that is processed and boosted via the platform facilities to attain the required injection pressure. Occasionally seawater is recovered, treated and then injected into the well from a platform.
Most producing fields involve numerous spaced apart wells and the injection wells are often positioned on the perimeter of the reservoir. Thus, the injections wells are typically positioned well away from the field pumping facilities requiring that utilization of centralized injections platforms connected to the various injection wells via submarine pipelines. It is therefore a desire to provide a pumping system that may be positioned at a point of need, below the surface of a body of water, for the purposes such as, without limitation, injecting raw seawater into one or more subterranean wells, producing a fluid from a wellbore, propelling a pig for pigging pipelines or dewatering flooded pipelines
An example of a pumping system includes a frame and a pump having an intake and a discharge, the pump being mounted within the frame such that the pump is oriented substantially parallel to the surface upon which the frame is supported. The pump and frame may be positioned below the surface of a body of water and the discharge of the pump connected to a wellbore. The pump and the frame may be positioned below the surface of a body of water and the discharge of the pump connected to a pipeline. The pump and the frame may be positioned below the surface of a body of water and the intake of the pump connected to a wellbore or pipeline
An example of a subsea, seawater injection system positionable on a seabed for connection to a subterranean well includes a frame, an electrical submersible pump (ESP) positioned in the frame so as to be oriented substantially parallel to the seabed when positioned thereon, and a filter operationally positioned between a source water intake and the ESP.
An example of a subsea raw seawater injection system includes an electric submersible pump having a discharge connected to a subterranean well, the electric submersible pump being positioned at, and substantially parallel to, a seabed; a seawater intake positioned above the seabed; and a filter operationally connected between the seawater intake and the electric submersible pump.
The foregoing has outlined some of the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.
The foregoing and other features and aspects of the present invention will be best understood with reference to the following detailed description of a specific embodiment of the invention, when read in conjunction with the accompanying drawings, wherein:
Refer now to the drawings wherein depicted elements are not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several views.
The system is described herein as a seawater injection system and is primarily described in terms of utilization as a point of injection seawater injection system. As will be better understood in the further description below, the present system is adapted for deployment subsea, permanently or temporarily, and may be utilized for various pumping applications. For example, and without limitation, the system may be utilized for boosting the fluid production from a wellbore into a pipeline or to a production facility, for dewatering pipelines or wells, and for pipeline pigging.
System 10 is illustrated as a point of injection system, positioned at or proximate to an injection well or wellbore 16. System 10 includes a deployment skid denoted generally by the numeral 18. Skid 18 is a frame structure adapted for containing and supporting various sub-systems and apparatus of system 10. As will be further noted below, various sub-systems and apparatus may be modular to facilitate maintenance and replacement in a subsea environment.
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Filters 22 are sized to pass source water 15 at a sufficient flow rate, for example 15,000 to 20,000 barrels per day, without plugging filters 22 or causing unnecessary friction loss. Filters 22 may be conventional downhole premium screens laid in a horizontal fashion. Filters 22 are utilized to prevent debris from being injected into well 16.
Pump 20 is an electrical submersible pump (ESP) that is commonly used in the petroleum industry for positioning at the bottom of a wellbore for producing a fluid. It is conceived that the ESP may be positioned horizontal relative to seabed 12 when it is deployed. Traditionally ESPs are positioned vertically in a wellbore. The present system orients pumps 20 such that when the system is deployed, pumps 20 are positioned substantially parallel to the surface upon which they are landed. For example, in
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System 10 may further include an operation system or package generally denoted by the numeral 36 in
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Electrical submersible pumps 20 are positioned so as to operate in a horizontal position (relative to the seabed) when deployed as opposed to the traditional vertical orientation of ESPs. The horizontal orientation enables a rapid build and deployment of the system and eliminates the need for precision placement of the system atop the wellbore. In the illustrated example, system 10 is deployed proximate to well 16 via a work ship 38. Once on the sea floor system 20 can be piped to well 16 and intake 24 deployed in the water column.
From the foregoing detailed description of specific embodiments of the invention, it should be apparent that a point of need pumping system that is novel has been disclosed. Although specific embodiments of the invention have been disclosed herein in some detail, this has been done solely for the purposes of describing various features and aspects of the invention, and is not intended to be limiting with respect to the scope of the invention. It is contemplated that various substitutions, alterations, and/or modifications, including but not limited to those implementation variations which may have been suggested herein, may be made to the disclosed embodiments without departing from the spirit and scope of the invention as defined by the appended claims which follow.