Patent Grant
8807227
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
This disclosure relates to methods and apparatuses for pressure testing tubular bodies, for example casing or tubing strings installed in subterranean wells.
During the construction of subterranean wells, it is common, during and after drilling, to place a tubular body in the wellbore. The tubular body may comprise drillpipe, casing, liner, coiled tubing or combinations thereof. The purpose of the tubular body is to act as a conduit through which desirable fluids from the well may travel and be collected. The tubular body is normally secured in the well by a cement sheath. The cement sheath provides mechanical support and hydraulic isolation between the zones or layers that the well penetrates. The latter function is important because it prevents hydraulic communication between zones that may result in contamination. For example, the cement sheath blocks fluids from oil or gas zones from entering the water table and polluting drinking water. In addition, to optimize a well's production efficiency, it may be desirable to isolate, for example, a gas-producing zone from an oil-producing zone.
Conventionally, production tubing is placed inside the casing in the vicinity of the zone from which hydrocarbons are extracted. The production tubing is generally hydraulically isolated by a packer that seals the production tubing/casing annulus.
A tubingless completion is one in which relatively small-diameter production casing is used to produce the well without the need for production tubing. The advantage of such completions is economic in that it may save five to six days rig time. Operations such as running and cementing liner, wellbore cleanup and packer setting procedures are eliminated.
After running the production casing into the wellbore, and prior to performing the cement job, it may be necessary to perform a pressure test of the casing string. There are three common methods by which this may be accomplished.
A plug may be run down the casing via slickline, after which the fluid between the surface and the plug is pressurized to the desired level. After the test, the plug is pulled out of the hole. The disadvantage of this technique is that the portion of casing below the plug is not tested.
A calibration plug may be used. In this method a first plug is circulated down the casing and it lands on a landing collar. The string can then be pressure tested. This is simple and reliable; however, to reestablish communication between the casing interior and the annulus, the pressure inside the string must be increased to a higher level to open a port (usually a burst disk). This operation may also be costly because of the rig time necessary to circulate the plug downhole.
A ball may be pumped. A ball seat is set in the casing string. When the ball lands, the string can be pressure tested. However, the ball must be sheared out at a higher pressure after the test, possibly compromising casing integrity.
The Applicant discloses herein improved methods and apparatuses for pressure testing tubular bodies employed as production casing in a subterranean well.
In an aspect, embodiments relate to pressure-testing apparatuses comprising an activation-device seat, one or more bypass ports, a J-slot with an indexing pin and a spring. Such an apparatus may be installed inside a tubular body between a landing collar and float equipment. The tubular body may comprise drillpipe, casing or coiled tubing, and the activation device may be a ball, dart, bomb or canister. The float equipment may be a float shoe, or a float collar and a float shoe.
In a further aspect, embodiments relate to methods for pressure testing a tubular body inside the borehole of a subterranean well. The pressure-testing apparatus described above is installed inside the tubular body, between the float equipment at the bottom of the tubular body and below a landing collar inside the tubular body. The tubular body is then lowered into the wellbore. A process fluid is circulated down the tubular body and into the annulus between the tubular body and the wellbore wall. The process fluid may be drilling fluid, a completion fluid, spacer fluid or a chemical wash. An activation device, which may be a ball, dart, bomb or canister, is inserted into the process fluid, whereupon it lands and becomes lodged in the activation-device seat. Process fluid is pumped until the pressure inside the tubular body reaches the desired level. The pressurization of the tubular body causes the indexing pin to travel to the bottom of the J-slot. After the pressure test, process-fluid pumping ceases. The resulting pressure reduction inside the casing causes the indexing pin to travel to the top of the J-slot, which in turn releases the spring and opens the bypass ports. The opening of the bypass ports restores fluid communication between the casing interior and the annulus.
In yet a further aspect, embodiments relate to methods for cementing a subterranean well having a borehole. The pressure-testing apparatus described above is installed inside the tubular body, between the float equipment at the bottom of the tubular body and below a landing collar inside the tubular body. The tubular body is then lowered into the wellbore. A process fluid is circulated down the tubular body and into the annulus between the tubular body and the wellbore wall. The process fluid may be drilling fluid, a completion fluid, spacer fluid or a chemical wash. An activation device, which may be a ball, dart, bomb or canister, is inserted into the process fluid, whereupon it lands and becomes lodged in the activation-device seat. Process fluid is pumped until the pressure inside the tubular body reaches the desired level. The pressurization of the tubular body causes the indexing pin to travel to the bottom of the J-slot. After the pressure test, process-fluid pumping ceases. The resulting pressure reduction inside the casing causes the indexing pin to travel to the top of the J-slot, which in turn releases the spring and opens the bypass ports. The opening of the bypass ports restores fluid communication between the casing interior and the annulus, allowing the well operator to proceed with the cementing operation.
This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
At the outset, it should be noted that in the development of any such actual embodiment, numerous implementation—specific decisions must be made to achieve the developer's specific goals, such as compliance with system related and business related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time consuming but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. In addition, the composition used/disclosed herein can also comprise some components other than those cited. In the summary and this detailed description, each numerical value should be read once as modified by the term “about” (unless already expressly so modified), and then read again as not so modified unless otherwise indicated in context. Also, in the summary and this detailed description, it should be understood that a concentration range listed or described as being useful, suitable, or the like, is intended that any and every concentration within the range, including the end points, is to be considered as having been stated. For example, “a range of from 1 to 10” is to be read as indicating each and every possible number along the continuum between about 1 and about 10. Thus, even if specific data points within the range, or even no data points within the range, are explicitly identified or refer to only a few specific, it is to be understood that inventors appreciate and understand that any and all data points within the range are to be considered to have been specified, and that inventors possessed knowledge of the entire range and all points within the range.
As discussed earlier, the present disclosure provides improved apparatuses and methods for pressure testing a tubular body. The tubular body is preferably one that is placed in the borehole of a subterranean well. The disclosure is also particularly aimed at (but not limited to) tubingless completions.
In an aspect, embodiments relate to apparatuses for pressure-testing. Schematic diagrams of the disclosed apparatus and its operation are shown in
Initially, the activation-device seat is open (
The tubular body may comprise (but would not be limited to) drillpipe, casing or coiled tubing, and the activation device may be a ball, dart, bomb or canister. The float equipment may be a float shoe, or a float collar and a float shoe. The process fluid may be (but would not be limited to) drilling fluid, completion fluid, spacer fluid or a chemical wash. The activation device may be (but would not be limited to) a ball, a dart, a bomb or a canister.
A chemical substance may also be encapsulated within the activation device. At a desired time after deployment of the device into the process fluid, the chemical substance may be released into the process-fluid stream.
In a further aspect, embodiments relate to methods for pressure testing a tubular body inside the borehole of a subterranean well. The pressure-testing apparatus 100 described earlier may be installed inside a tubular body 105, thereby creating an annulus between the tubular-body exterior and the borehole. The apparatus is preferably located above float equipment 302 and below a landing collar 301. The tubular body may comprise drillpipe, casing or coiled tubing. The tubular body is then lowered into the borehole (
An activation device 201 may be inserted into the process fluid stream, and process-fluid circulation may continue until the activation device lands in the activation-device seat (
In yet a further aspect, embodiments relate to methods for cementing a subterranean well having a borehole. The pressure-testing apparatus 100 described earlier may be installed inside a tubular body 105, thereby creating an annulus between the tubular-body exterior and the borehole. The apparatus is preferably located above float equipment 302 and below a landing collar 301 (
An activation device 201 may be inserted into the process fluid stream, and process-fluid circulation may continue until the activation device lands in the activation-device seat. The activation device may be (but would not be limited to) a ball, a dart, a bomb or a canister. Upon landing in the activation-device seat, the activation device blocks fluid communication between the tubular-body interior and the annulus. Continued pumping of process fluid into the tubular-body interior pressurizes the casing. Process fluid is pumped until the pressure inside the tubular body reaches the desired level. During this step, the activation-device seat moves downward, compressing the spring 104. At the same time, the indexing pin 103 moves to the bottom position 201 of the J-slot 202. Next, process-fluid pumping stops, thereby releasing pressure within the tubular-body interior. The pressure reduction causes the activation-device to move upward, and the indexing pin moves to the top position 204 and the spring decompresses. This upward movement unblocks the bypass ports 102, thereby reestablishing fluid communication between the tubular-body interior and the annulus, and allowing process-fluid to circulate again. Cement slurry 304 may then be pumped into and circulated in the well (
Those skilled in the art will appreciate that, at a later stage, the apparatus may be configured to be retrievable by, for example, slickline. Or, the apparatus may be milled out by, for example, a drilling apparatus mounted on coiled tubing. Such operations would restore full and unhindered access to the wellbore.
Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this disclosure. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.
This application claims the benefit of the disclosure of U.S. provisional application No. 61/427,277 incorporated by reference in its entirety.
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