Patent Application
20100326670
1. Field of Disclosure
In general, embodiments of the present disclosure generally provide methods and apparatuses for pumping fluid from a wellbore. More specifically, embodiments disclosed herein relate to a single apparatus that facilitates both producing hyrocarbons and circulating fluid downhole.
2. Background Art
Typically, wells employ a pump system configuration for extracting oil and gas from the earth. A conventional oil well pumping system incorporates a down hole pump, a sucker rod string extending from the down hole pump to the surface and a pump jack or pumping unit at the surface attached to the upper end of the sucker rod string for reciprocating the sucker rods and activating the down hole pump. An example of such conventional pump system is shown in
During the process of extracting oil and gas using a pumping system as described above, it is often desirable to remove all solid materials in the well bore as well as removal of cement, debris, metal and other materials which may cling to the wall of the tubular or may be laying on the side or bottom of a partially horizontal tubular. Currently this process is accomplished by running a tubular (commonly called a “work string”) in to or near the bottom of the well. Fluid is then circulated through or down the work string and into the annulus between the tubular and wellbore. More specifically, water or other fluids are pumped down the wellbore through the work string and out the bottom of the string. The fluid flows through the annulus between the work string and the wellbore and out the surface, carrying away any matter loosened during workover or production phases of the well.
Circulation is accomplished by pumping fluid down the work string and back to the surface through the annulus between the work string and casing. Often times, the pumping system used to extract oil and gas from the wellbore is replaced by a separate system configured to perform wellbore circulation. Thus, the pumping system used for extraction of oil and gas may be removed from the wellbore entirely to allow for the work string to be inserted downhole to treat the wellbore. Applications requiring different tools for production and circulating of fluids in the wellbore can increase the cost of production due to the cost of the tools, the cost of changing the tools, and costs associated with production downtime.
Therefore, there exists a need for a more efficient production system.
In one aspect, embodiments disclosed herein include an apparatus for pumping fluid, the apparatus including a pump housing including a plunger connected to a terminal end of a coiled tubing and a first port. The apparatus further including the plunger configured to move longitudinally upward and downward, wherein the plunger includes a second port and a surface pumping unit configured to modulate between two modes, a first mode configured to limit a stroke length of the plunger so that the first and second ports do not engage, and a second mode wherein the first and second ports engage.
In another aspect, embodiments disclosed herein include a method for pumping fluid into a wellbore using an apparatus, the method comprising inserting a housing including a coiled tubing and a plunger into the wellbore, wherein the plunger is located at a terminal end of the coiled tubing, and wherein the housing includes a first port and a plunger includes a second port. The method further including moving the plunger longitudinally upward and downward within the housing wherein a stroke length of the plunger is limited during the moving the plunger and extracting fluid from the wellbore. The method further including extracting fluid from th wellbore, pulling the plunger longitudinally upward until the first and second ports are aligned, and circulating fluid into the wellbore through the coiled rubbing and first and second ports discharging into an annulus of the wellbore.
Other aspects of the invention will be apparent from the following description and the appended claims.
Specific embodiments of the disclosure will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency.
In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.
In general, embodiments of the disclosure provide a method and apparatus for pumping fluid from a wellbore. More specifically, embodiments disclosed herein relate to a single apparatus that facilitates both producing hyrocarbons and circulating fluid downhole.
In one or more embodiments disclosed herein, a first port (108) exists on the plunger (106), and a second port (110) exists on the housing (104). The first port (108) may be any object, such as a protrusion, a recess, an indentation, a hole, etc. configured to mate (i.e., engage) with the second port (110). In one or more embodiments of the disclosure, the first and second port do not engage or align during normal pumping activity, i.e., when oil and/or gas is extracted from the wellbore. However, the first and second ports (108, 110) are configured to align when the apparatus (100) is in circulation mode (described in detail below).
In one or more embodiments disclosed herein, a surface pumping unit (not shown) is operatively connected to the coiled tubing (102). The surface pumping unit includes a bridle and bridle cables that are configured to attach and grab a specific location along the length of the coiled tubing (102). In one or more embodiments disclosed herein, the surface pumping unit is configured to limit the amplitude of the pump stroke that is performed by the plunger (106). The surface pumping unit is configured to limit the stroke of the plunger to a down stroke limit and to an up stroke limit. Limiting the stroke prevents the first and second ports from coinciding (i.e., engaging), when the apparatus (100) is not in circulation mode.
In
In
In
Those skilled in the art will appreciate that the example profiles shown in
In certain embodiments, profiles (300, 302) are configured to engage and mate with one another upon rotation of the plunger relative to the housing. Because the housing is stationary within the wellbore, the coiled tubing may be rotated from the surface, thereby rotating the plunger as the plunger is pulled longitudinally upward toward the surface. As the plunger is pulled longitudinally upward, profiles (300, 302) slidably engage one another. The sliding engagement may occur, for example, as profile 300 of the plunger rotates relative to profile 302 of the housing. Because the plunger may rotate within the housing, profile 300 of the plunger may also rotate relative to profile 302 of the housing during engagement. While profiles (300, 302) are engaged, fluid may flow from the surface, through the coiled tubing, out of the ports, and into the annulus of the borehole. In alternate embodiments, a swivel may be used in the plunger or the coiled tubing to facilitate alignment of profiles (300, 302) as the profiles (300, 302) engage one another. Those of ordinary skill in the art will appreciate that various types of swivels may be used, such as, for example, a cylindrical rod disposed within a support structure and configured to rotate horizontally therein.
The surface pumping unit then moves the plunger in a pump motion, longitudinally upward to the up stroke limit and then longitudinally downward to the down stroke limit (ST 406). The up stroke limit and the down stroke limit may vary according to design constraints of a particular operations. For example, in certain operations, the stroke limits may be determined based on the length or internal diameter of the plunder or housing. In other operations, the stroke limits may be determined based on the type of fluid being produced, the volume of fluid being produced, the pressure of the system, etc.
When required, the pump apparatus may be placed in circulation mode. Circulation mode may be required as part of conventional maintenance operations to maintain the integrity of and clean debris from the wellbore. To facilitate circulation mode, the grip of the surface pumping unit along the length of the coil tubing is adjusted such that the bridle of the surface pump grabs the coiled tubing at a location below the original location (ST 408). By adjusting the grip of the surface pumping unit, the plunger may be pulled upward past the up stroke limit, thereby pulling the plunger to the top-most position within the housing (ST 410). When the plunger is pulled to the top-most position within the housing, the ports on the housing and the plunger engage and align (ST 412). The engagement of the ports facilitates the circulation of fluids to treat the wellbore during circulation mode.
In certain embodiments, when the pump apparatus is placed in circulation mode, the coiled tubing or plunger may be rotated, thereby causing the ports of the housing and plunger to align. In certain embodiments, the pump apparatus may include a swivel, thereby allowing the profiles to engage and align the ports. In other embodiments, the profiles of the ports engage and mate upon contact, as the plunger is pulled longitudinally upward. As such, the pump apparatus may include ports with self-aligning profiles, thereby providing a flow path between the pump apparatus and the annulus of the wellbore.
More specifically, during circulation, fluid is circulated downstream into the wellbore and back up through the annulus. In one or more embodiments of the disclosure, the plunger is stationary when the apparatus is placed in circulation mode. Alternatively, the plunger may be reciprocated to provide intermittent circulation or jetting.
In certain embodiments, fluids may be forced into the well and/or reservoir against pressure in a process referred to in the art as “bullheading.” Bullheading may be used to chemically and/or physically treat the well and/or reservoir to, for example, improve production, prevent corrosion, prevent scale deposition etc. . . .
Advantageously, embodiments of the disclosure provide a single apparatus that facilitates both extraction of wellbore production fluids and the circulation of fluids to treat the wellbore. The apparatus of the present disclosure eliminates the need for a separate circulation apparatus, and provides an efficient, quick, and low cost apparatus and method for combining the aforementioned processes during workover and production.
Advantageously, embodiments of the present disclosure may provide self-aligning port profiles that allow movement of a plunger of the pump apparatus to provide a flow path from the surface to the annulus of the wellbore. Because the port profiles are self-aligning, the pump apparatus may efficiently modulate between production and circulating modes. By allowing faster maintenance and cleaning operations, the wellbore may be cleaned and maintenance may be performed without lengthy and expensive operations that may involve removing the pump apparatus or a portion of the pump apparatus from the wellbore.
While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.
