The disclosure relates generally to production of fluid from subterranean reservoirs.
Fluids are typically produced from a reservoir in a subterranean formation by drilling a wellbore into the subterranean formation, establishing a flow path between the reservoir and the wellbore, and conveying the fluids from the reservoir to the surface through the wellbore. Typically, a production tubing is disposed in the wellbore to carry the fluids to the surface. The production tubing may include a pump to assist in lifting the fluids up the wellbore. Fluids produced from a hydrocarbon reservoir may include natural gas, oil, and water. One common challenge in producing fluids from a hydrocarbon reservoir through a wellbore is the ability to continuously lift clear volumes of oil or gas (i.e., volumes in which water is not mixed with the oil or gas) to the surface relatively inexpensively and without disturbing the fluid system.
A method for hydrocarbon production includes forming a wellbore in a subterranean formation, disposing a tool comprising a fluid dispenser and at least one proximity sensor in the wellbore, positioning the fluid dispenser at an initial depth in an end section of the wellbore, providing an acidic aqueous solution to the fluid dispenser, and forming a cavern of a select height in the end section of the wellbore with the tool. The cavern is formed by rotating the fluid dispenser to distribute the acidic aqueous solution to a portion of the subterranean formation surrounding the fluid dispenser, wherein the acidic aqueous solution dissolves a rock material in the portion of the subterranean formation; measuring a distance between the tool and the portion of the subterranean formation surrounding the fluid dispenser using the at least one proximity sensor; and adjusting a position of the fluid dispenser to another depth in the end section of the wellbore if the distance measured is at or above a predetermined threshold. The tool may be lowered into the wellbore on an end of a coiled tubing. The acidic aqueous solution may be provided to the fluid dispenser through the coiled tubing. The wellbore may be formed in a carbonate formation comprising a hydrocarbon reservoir. The initial select depth of the fluid dispenser may be proximate a bottom of the wellbore. The position of the fluid dispenser may be adjusted to another select depth in the end section of the wellbore by raising the fluid dispenser to the another select depth. The cavern formed may have a cylindrical side wall and a dome shaped top wall. The tool may be removed from the wellbore after forming the cavern, and the cavern may be filled with brine. A production tubing may be disposed in the wellbore. The production tubing may be in communication with the cavern. The brine from the cavern may be withdrawn through the production tubing. Fluids from the subterranean formation may flow into the cavern as the brine is withdrawn from the cavern. The fluids from the subterranean formation may be stratified by gravity inside the cavern. The method may include withdrawing the stratified fluids from the cavern through the production tubing. The brine and stratified fluids may be withdrawn from the cavern through the production tubing by operating a pump disposed in the production tubing.
A tool for forming a cavern for hydrocarbon production includes a housing having a cavity, a rotary actuator disposed in the cavity, and a fluid dispenser having an internal chamber to receive an aqueous solution and at least one nozzle to dispense the aqueous solution. The fluid dispenser is coupled to the rotary actuator and rotatable about a tool axis by the rotary actuator. The tool includes at least one proximity sensor disposed at a perimeter of the housing to measure a distance relative to the tool. The at least one proximity sensor may be an ultrasonic sensor. The sensing direction of the at least one proximity sensor may be perpendicular to the tool axis. The sensing direction of the at least one proximity sensor may be inclined to the tool axis. The fluid dispenser may include a plurality of nozzles to dispense the aqueous solution. At least one of the plurality of nozzles may have a straight shape, and at least another one of the plurality of nozzles may have an angled shape. The tool may include a support tube that is coupled to the housing. The support tube may have a bore that is fluidly connected to the internal chamber.
A system for forming a cavern includes a wellbore traversing a subterranean formation, a coiled tubing supported by a reel, and a tool for forming a cavern disposed in the wellbore on an end of the coiled tubing. The tool includes a housing having a cavity, a rotary actuator disposed in the cavity, and a fluid dispenser fluidly connected to the coiled tubing. The fluid dispenser has an internal chamber to receive fluid from the coiled tubing and at least one nozzle to dispense the fluid. The fluid dispenser is coupled to the rotary actuator and rotatable about the tool axis by the rotary actuator. The tool includes a fluid path between the internal chamber and the coiled tubing. The tool includes at least one proximity sensor disposed at a perimeter of the housing to measure a distance between the subterranean formation and the tool. The system may include a tank containing an acidic aqueous solution. The system may include a pump to transfer the acidic aqueous solution from the tank to the coiled tubing.
The foregoing general description and the following detailed description are exemplary of the invention and are intended to provide an overview or framework for understanding the nature of the invention as it is claimed. The accompanying drawings are included to provide further understanding of the invention and are incorporated in and constitute a part of the specification. The drawings illustrate various embodiments of the invention and together with the description serve to explain the principles and operation of the invention.
The following is a description of the figures in the accompanying drawings. In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not necessarily drawn to scale, and some of these elements may be arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn are not necessarily intended to convey any information regarding the actual shape of the particular elements and have been solely selected for ease of recognition in the drawing.
In the following detailed description, certain specific details are set forth in order to provide a thorough understanding of various disclosed implementations and embodiments. However, one skilled in the relevant art will recognize that implementations and embodiments may be practiced without one or more of these specific details, or with other methods, components, materials, and so forth. In other instances, well known features or processes associated with the hydrocarbon production systems have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the implementations and embodiments. For the sake of continuity, and in the interest of conciseness, same or similar reference characters may be used for same or similar objects in multiple figures.
System 100 includes a production tubing 140, which is disposed in wellbore 110. Production tubing 140 extends into cavern 130, thereby forming a flow conduit from cavern 130 to surface 126. Production tubing 140 may include an electrical submersible pump (ESP) 142, which may be powered by a cable 144 from surface 126. A packer 146 may be arranged to seal an annulus 148 between production tubing 140 and wellbore 110 from cavern 130. A packer 150 may be arranged in annulus 148 and above ESP 142. A casing 152 may be installed in wellbore 110, and annulus 148 may be formed between production tubing 140 and casing 152. Annulus 148 may be filled with brine 136. At surface 126, fluids from production tubing 140 may be received in a separator 170, which may then operate to separate the fluids into oil, water, and gas. The separated fluids may be diverted into respective flow lines 172, 174, 176.
A method of producing hydrocarbons with system 100 may include operating ESP 142 to gradually withdraw brine 136 from cavern 130. As brine 136 is withdrawn from cavern 130, as shown in
In one implementation, the method of producing hydrocarbons includes forming cavern 130 prior to producing fluids from cavern 130.
Rotary table 240 includes a housing 242, which may be generally cylindrical in shape. Housing 242 has an axial axis that is aligned with tool axis 202. Within housing 242 is a rotary actuator 250. In one example, rotary actuator 250 is a hollow shaft motor. A hollow shaft motor has a hole running through the center of the motor. This permits tube 226 of fluid dispenser 220 to be assembled to the rotor of the motor. As the rotor rotates, tube 226 will be rotated, which will cause fluid dispenser 220 as a whole to be rotated. In the illustrated example of
In one implementation, proximity sensors 260 are disposed at a perimeter 246 of housing 242, that is, sensing faces 262 of proximity sensors 260 are exposed at the perimeter of housing 242. Proximity sensors 260 may be used to measure a distance between housing 242 and a surrounding object, such as a surrounding formation. During use of tool 200, proximity sensors 260 can measure a parameter related to a radius of a cavern being formed by tool 200. The measurements made by proximity sensors 260 can be used to make decisions about when to move tool 200 to another depth in order to form another portion of the cavern. In one implementation, proximity sensors 260 are ultrasonic sensors. In one example, an ultrasonic sensor works by transmitting an ultrasonic pulse and receiving a reflection of the pulse. The distance to the object can be determined from the time difference between the transmitted pulse and reflected pulse. In some cases, cable 258 may provide electrical power to proximity sensors 260 (260′). Cable 258 may also serve as a medium for transmitting measurements from proximity sensors 260 to a control system at a surface location. The control system may include a processor that receives measurements from proximity sensors 260 and uses the measurements to determine whether to adjust the position of tool 200 during forming of a cavern with tool 200.
One or more proximity sensors 260 may be arranged on perimeter 246 of housing 242 for the purpose of sensing the distance between housing 242 and a surrounding element. In the illustrated example of
System 300 includes a tank 350 containing an aqueous solution that will be used to etch formation 322 in order to form the cavern. System 300 includes a pump 352 to pump the aqueous solution from tank 350 into coiled tubing 340. The aqueous solution pumped into coiled tubing 340 will flow into support tube 210 of tool 200 and into fluid dispenser 220 of tool 200, where the fluid can be jetted out through nozzles 230, 232 and directed towards the surrounding formation 322. The jet speed can be controlled by the pressure of the aqueous solution supplied into fluid dispenser 220.
The method includes forming a cavern of a select height in end section 332 of wellbore 330. The cavern is formed in sections. To form a section of the cavern, the method includes rotating fluid dispenser 220 to distribute the acidic aqueous solution to a portion of formation 322 surrounding fluid dispenser 220 at the current depth of fluid dispenser 220 (406 in
In the illustrated example, straight nozzles 230 form a cylindrical portion 312a of cavern portion 310a, and angled nozzles 232 form a dome shaped portion 312b of cavern portion 310a. Fluid dispenser 200 may be positioned at the next depth such that straight nozzles 230 will etch the dome shaped portion of a previous cavern portion, while angled nozzles 232 will form another dome shaped portion. This next position (from the position shown in
The method includes determining if the cavern has reached a desired height (414 in
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate that other embodiments can be devised that do not depart from the scope of the invention as described herein. Accordingly, the scope of the invention should be limited only by the accompanying claims.
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International Search Report and Written Opinion issued in corresponding International Application No. PCT/US2020/028610, dated Dec. 7, 2020 (15 pages). |
Number | Date | Country | |
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20210293092 A1 | Sep 2021 | US |