Patent Application
20150114663
1. Field of the Disclosure
The disclosure herein relates generally to the methods and devices for artificial gas lift operations in hydrocarbon producing wells.
2. Background of the Art
Hydrocarbon production systems typically rely on formation pressure from subterranean reservoirs to produce hydrocarbon fluids and gases. In a naturally flowing well, there is enough energy stored in the high pressure reservoir to produce liquids and gases to the surface. When this reservoir energy decreases, it is generally necessary to apply some form of artificial lift to assist in producing these liquids and gases to the surface.
Gas lift is a form of artificial lift that is used to assist in producing boreholes that do not flow or cannot flow at optimum or desired producing rates. Gas lift systems generally include a mechanism for injecting high pressure gas from an annular region of the well into a production conduit. Conventionally, a valve actuated by using control lines is used in gas lift systems to control flow of the high pressure gas into the production conduit.
The present disclosure is directed to methods, devices, and system for gas lift arrangements that do not use control lines for actuating such valves.
In aspects, the present disclosure provides a system for producing hydrocarbons from a well having a borehole. The system may include a production flow line disposed in the borehole and a production control device positioned along the production flow line. The production control device may include an enclosure having an interior space, an isolation device disposed in the interior space, the isolation device dividing the interior space into an upper interior space and a lower interior space, a first flow control device positioned in the upper interior space and controlling flow along the production flow line, and a second flow control device positioned in the upper interior space and controlling fluid flow between the upper interior space and the lower interior space. The first flow control device may be responsive to a control signal transmitted via a control line from a surface location. The second flow control device may reactively block fluid flow from the lower interior section to the upper interior section when a pressure differential between the upper interior space and the lower interior space falls below a preset value.
In aspects, the present disclosure provides a method for producing hydrocarbons from a well having a borehole. The method may include disposing a production flow line in the borehole; positioning a production control device along the production flow line, the production control device including an enclosure having an interior space, an isolation device disposed in the interior space, the isolation device dividing the interior space into an upper interior space and a lower interior space; controlling flow along the production flow line using a first flow control device positioned in the upper interior space, the first flow control device being responsive to a control signal transmitted via a control line from a surface location, and controlling fluid flow between the upper interior space and the lower interior space using a second flow control device positioned in the upper interior space, the second flow control device reactively blocking fluid flow from the lower interior section to the upper interior section when a pressure differential between the upper interior space and the lower interior space falls below a preset value.
Examples certain features of the disclosure have been summarized rather broadly in order that the detailed description thereof that follows may be better understood and in order that the contributions they represent to the art may be appreciated. There are, of course, additional features of the disclosure that will be described hereinafter and which will form the subject of the claims appended hereto.
For a detailed understanding of the present disclosure, reference should be made to the following detailed description of the embodiments, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals, wherein:
In aspects, there is provided apparatuses and methods for controlling hydrocarbon production in a borehole in an earth formation. A production assembly such as a production string is configured to be disposed in a borehole and facilitate production of hydrocarbons (e.g., oil and/or gas). A flow control device associated with the production assembly selectively allows pressurized gas to flow into the production assembly to provide lift and facilitate hydrocarbon production. As discussed below, the flow control devices according to the present disclosure may be configured to react to changes in pressure differentials and therefore open and close without using control lines from the surface.
Referring to
Referring to
The production flow line 114 may include a flow control device such as a safety valve 115 that is actuated between an open and a closed position along the production flow line 114. By “closed,” it is meant the flow control device 115 blocks fluid flow across the production string 114. The control line 116 penetrates the enclosure 110 and leads to the control facility 125 (
The flow control device 120 reactively controls the flow of gas between the upper interior space 122 and the lower interior space 124 of the enclosure 110. The flow control device 120 may include a valve 136 configured to admit the gas from the upper interior space 122 into a conduit 138 in the isolation device 132. The conduit 138, which is shown in hidden lines, allows fluid communication between the upper and lower interior spaces 122, 124.
The flow control device 120 reactively controls fluid flow because the valve 136 is responsive to a pre-determined pressure differential value between the upper interior space 122 and the lower interior space 124. For example, the valve 136 may be configured to open when the pressure in the upper interior space 122 is greater than the pressure in the lower interior space 124, or a “positive” pressure differential, which indicates a fluid flow in the downhole direction. The valve 136 responsively closes if and when the positive pressure differential is below the preset threshold value. The valve 136 may be any uni-directional flow control device. For example, the valve 136 may be a reverse flow check valve that prevents pressurized gases from flowing from the lower interior space 124 to the upper interior space 122. It should be appreciated that the valve 136 may be opened and closed by controlling a flow parameter of the gas being pumped into the well annulus 119. That is, controlling the pressure or flow rate of the gas being pumped into the well annulus 119 controls operation of the valve 136. Thus, separate control lines are not needed to actuate the valve 136. By “open,” it is meant the flow control device 120 allows fluid flow across the conduit 138. By “closed,” it is meant the flow control device 120 blocks fluid flow across the conduit 138. By “reactively,” it is meant that the valve actuates to the closed position autonomously and without a signal transmitted from the surface; e.g., a hydraulic signal sent from the surface via a control line connected to the second flow control device.
In one mode of operation, the surface facility 125 pumps a lifting gas into the annulus 119. The gas flows down the borehole 12 and enters the upper interior space 122. As long as the preset threshold positive pressure differential value is exceed between the upper interior space 122 and the lower interior space 124, the valve 136 remains in an open position and allows fluid communication in the downhole direction. As the gas fills the lower interior space 124, the resident liquids are displaced such that the injection inlets 130 are successively exposed. Typically, liquids are displaced until the liquid line is below the lowest injection inlet 130. Now, gas flows into the mandrels 129 via the injection inlet 130 mixes with the formation liquids in the mandrels 129. The addition of the gas reduces the density of the formation liquids and allows these liquids to flow via the production flow line 114 to the surface.
Either intentionally or unintentionally, the pressure differential at the isolation device 112 may drop below the threshold positive pressure differential value. In such an instance, the valve 136 reacts to the drop in the pressure differential and closes to block fluid flow from the lower interior space 124 to the upper interior space 122 via the conduit 138. For example, surface operators may deliberately reduce the pressure of the gas being pumped into the well annulus 119 in order to close the valve 136. It should be appreciated that the valve 136 is closed without using a communication signal from the surface via a separate control line. An unplanned closing of the valve 136 may occur if the borehole has encountered a fluid influx (e.g., a gas kick) or some other event that causes an increase in wellbore pressure in the lower interior space 124 or at a wellbore bottom 131. Such a pressure increase may lower the positive pressure differential below the threshold value and cause the valve 136 to automatically or reactively close. In such an instance, a well operator can use the control line 116 to transmit the control signal that causes the production valve 115 to close. Thus, when both flow control devices, valves 115, 136, are closed, the fluids in the borehole below the production packer 112 have been isolated and cannot flow to the surface.
The production control device 100, and the components making up the production control device 100, including the flow control device 120, may be retrieved from the borehole using a conveyance device such as a wireline, slickline, or other suitable non-rigid carrier. These components may include a suitable “fishing neck” or other similar retrieval mechanism to facilitate removal. Thus, when desired, a wireline (other suitable conveyance device) may be secured to a component (e.g., the flow control device 120) or the production control device 100, for extraction from the well.
As used here, the terms “above” and “below”; “up” and “down”; “upper” and “lower”; “upwardly”, “downwardly”; “up hole” and “down hole” and other like terms indicating relative positions above or below a given point or element are used in this description to more clearly describe some embodiments. However, when applied to equipment and methods for use in wells that are deviated or horizontal, such terms may refer to a left to right, right to left, or diagonal relationship as appropriate.
While the foregoing disclosure is directed to the one mode embodiments of the disclosure, various modifications will be apparent to those skilled in the art. It is intended that all variations within the scope of the appended claims be embraced by the foregoing disclosure.
