Patent Application
20160024865
1. Field of the Invention
The invention is directed to extraction devices, specifically, the invention is directed to devices for extraction downhole drilling equipment through the drillstring.
2. Background of the Invention
In the oil and gas industry, bores are drilled to access sub-surface hydrocarbon-bearing formations. Conventional drilling involves imparting rotation to a drillstring at surface, which rotation is transferred to a drill bit mounted on a bottom hole assembly (BHA) at the distal end of the string. However, in directional drilling a downhole drilling motor may be used to impart rotation to the drill bit.
During the drilling of horizontal oil and gas wells, for example, the trajectory of the wellbore is often uneven and erratic. The high tortuosity of a wellbore, brought about from geo-steering, directional drilling over corrections, and/or formation interaction, makes running multi stage expandable packer assembles or casing in such wells extremely difficult and sometimes impossible. While drilling long reach horizontal wells, the friction generated from the drillstring and wellbore interaction severely limits the weight transfer to the drill bit, thus lowering the rate of penetration and potentially causing numerous other issues and, in a worst case scenario, the inability to reach the total planned depth of the well. The BHA becomes stuck to the point that it cannot be pulled it out and the operator must find the point along the drillstring that is stuck. To determine the stuck point a “free point” test is used. The free point test involves a magnetic characterization of the drillstring, first without an imposed tension or torque and then once again with an imposed tension or torque. The magnetic profile of the drillstring should be the same for both sweeps except for an anomaly at the stuck portion. The concentrated stress at the stuck portion changes the magnetic profile of the material and thus the free point is determined.
The free point test can only be conducted with a clear bore. If mid-string equipment is in place the free point test can only be run down to the mid-string equipment. An example of mid-string equipment that is commonly installed is an agitator. Currently if there is not a clear bore and the drill string gets stuck, a tedious, time consuming, expensive operation is undertaken. The first step is to “back off” the mid-string equipment using a special break away component down hole of the mid-string equipment. Once the mid-string equipment is backed off the drill string from the mid-string equipment to the derrick is tripped out. Next the free point tool is sent down the open hole to insert it into the open, remaining drillstring and then conduct the magnetic characterizations. Once the free point is determined, a severing tool, chemical, explosive, or the like is inserted and the drill string is severed just up hole from the free-point. The section of drill string between the mid-string equipment and the free-point is retrieved. If possible the MWD is retrieved from the drill string. The final steps involve forcibly removing the stuck BHA and replacing it with a new BHA. Occasionally the BHA cannot be freed. In such cases the BHA is abandoned and drilling starts just above the stuck BHA with a deviated bore hole to go around the stuck drill string.
For the foregoing reasons, there is a need for a device and system to easily and quickly remove drilling equipment without disrupting the entire drillstring.
The present invention overcomes the problems and disadvantages associated with current strategies and designs and provides new tools and methods of removing drilling equipment through a drillstring.
An embodiment of the invention is directed an equipment extraction device. The device comprises an anchor coupled to the equipment. The anchor comprises an anchor extraction pin, and at least one anchor claw adapted to engage an interior portion of a drill string.
In a preferred embodiment, the equipment is one of a turbine-driven generator, an agitator, a measure while drill (MWD) device, a log while drill (LWD) device, a telemetry or downhole communications device, repeaters for the telemetry or communication device, instruments for measuring drillstring dynamics (e.g. torque, rotational rate, translation rate), an electrical turbine generator, a mid-string instrument cluster, an electrical generator, and combinations thereof. Preferably, the device further comprises a shear pin adapted to maintain the engagement of the at least one anchor claw in the interior portion of the drill string until a force is applied significant enough to overcome the strength of the shear pin.
Preferably, the device further comprises a housing couplable to an uphole portion of the drillstring and a stator tube couplable to a downhole portion of the drillstring. In a preferred embodiment, the interior portion of the drill string is an interior portion of the stator tube. The at least one anchor claw is preferably adapted to detachably engage holes, recesses, or openings in the interior portion of the stator tube. Preferably, the anchor and equipment are extractable from the housing and the stator tube.
In a preferred embodiment, once the anchor and equipment are extracted, a clear bore is left in the housing and the stator tube. Preferably, the device further comprises at least one slot in the stator tube, wherein drilling fluid is able to flow around the anchor and equipment, through the at least one slot, and into the stator tube. Preferably, the anchor extraction pin is adapted to be grappled from the surface.
Another embodiment of the invention is a system for extracting equipment from a drillstring. The system comprises an equipment extraction device having an anchor coupled to the equipment, wherein the anchor is comprised of an anchor extraction pin and at least one anchor claw, a housing coupled to an uphole portion of the drillstring, and a stator tube coupled to a downhole portion of the drillstring. The equipment extraction device is detachably coupled to the stator tube.
Preferably, the equipment is one of a turbine-driven generator, an agitator, a measure while drill (MWD) device, a log while drill (LWD) device, a telemetry or downhole communications device, repeaters for the telemetry or communication device, instruments for measuring drillstring dynamics (e.g. torque, rotational rate, translation rate), an electrical turbine generator, a mid-string instrument cluster, an electrical generator, and combinations thereof. In a preferred embodiment, the equipment extraction device further comprises a shear pin adapted to maintain the engagement of the at least one anchor claw in an interior portion of the stator tube until a force is applied significant enough to overcome the strength of the shear pin.
The system preferably further comprises a grappling device adapted to couple to the anchor extraction pin and extract the anchor and equipment from the drillstring. The system preferably further comprises multiple anchors each coupled to a different piece of equipment. Preferably, the at least one anchor claw is adapted to detachably engage holes, recesses, or openings in the interior portion of the stator tube.
In a preferred embodiment, the anchor and equipment are extractable from the housing and the stator tube. Preferably, once the anchor and equipment are extracted, a clear bore is left in the housing and the stator tube. The system preferably further comprises at least one slot in the stator tube, wherein drilling fluid is able to flow around the anchor and equipment, through the at least one slot, and into the stator tube. Preferably, anchor and equipment are extractable without removing the drillstring.
Other embodiments and advantages of the invention are set forth in part in the description, which follows, and in part, may be obvious from this description, or may be learned from the practice of the invention.
The invention is described in greater detail by way of example only and with reference to the attached drawing, in which:
As embodied and broadly described herein, the disclosures herein provide detailed embodiments of the invention. However, the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. Therefore, there is no intent that specific structural and functional details should be limiting, but rather the intention is that they provide a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention
In the preferred embodiment the anchor 100 and the equipment 105 are contained within drillstring via an uphole or surface facing housing 110 and a downhole or drill bit facing stator tube 115. The housing's 110 and the stator tube's 115 positions may be reversed in the drillstring. Preferably both anchor 100 and housing 110 are coupled to stator tube 115 during drilling. Preferably, during extraction of anchor 100 and equipment 105, the anchor 100 and the equipment 105 disengage from stator tube 115 and are pulled through the drillstring to the surface without disrupting or removing the drillstring from the hole and without disengaging housing 110 from stator tube 115. Preferably, housing 110 and stator tube 115 are coupled via a press fit, welded assembly. However, housing 110 and stator tube 115 can be coupled with adhesive, a threaded coupling, bolts, friction, rivets, snap together, or another coupling device. Preferably, at least a portion of stator tube 115 is inserted into housing 110, while another portion extends downhole beyond the end of housing 110.
Once the anchor 100 and equipment 105 are removed, a clear bore is left to the remaining portion of the drillstring, allowing for free point tests and measure while drilling (MWD) tool retrieval. For example, if the drill becomes stuck, the operator can pull on anchor extraction pin 120 to remove anchor 100 and rotor 105 through the drillstring, thereby providing a clear path to the downhole portions of the drillstring to determine where the drillstring is stuck or the drilling is otherwise stopped.
Other embodiments and uses of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. All references cited herein, including all publications, U.S. and foreign patents and patent applications, are specifically and entirely incorporated by reference. It is intended that the specification and examples be considered exemplary only with the true scope and spirit of the invention indicated by the following claims. Furthermore, the term “comprising of” includes the terms “consisting of” and “consisting essentially of.”
