THROUGH A DRILLSTRING

Background

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. Summary of the Invention

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.

Description of the Drawing

The invention is described in greater detail by way of example only and with reference to the attached drawing, in which:

Figure 1 is a cut away side view of an embodiment of the invention.

Figure 2 is a blown-up view of an embodiment of the anchor end of the invention.

Figure 3 is a blown-up view of an embodiment of an example of equipment end of the invention.

Description of the Invention

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 Figure 1 depicts a cutaway side view of an embodiment of an anchor 100 for removing equipment 105 from a drillstring 110. In the embodiments depicted herein, a turbine-driven generator is the equipment 105. However, equipment 105 can be, for example, 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 generator, a mid-string instrument cluster, an electrical turbine generator, or other drilling equipment and combinations thereof. While one anchor 100 is described, multiple anchors 100 can be deployed throughout the drillstring, each coupled to a different piece of equipment 105.

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.

Figure 2 depicts a blown-up view of the anchor 100 end of the system. The uphole end of anchor 100 is preferably comprised of an extraction pin 120. The extraction pin 120 preferably can be grappled, fished, or otherwise attached to by a device from the surface. The downhole end of anchor 100 is preferably comprised of an equipment mount 125 coupled to the anchor body 130. Preferably, anchor 100 and equipment 105 are held in place within stator tube 115 by anchor claws 135. Preferably, anchor claws 135 detachably engage holes, recesses, or other openings in the body of stator tube 115. Furthermore, a shear pin 140 or a spring detent detail maintains the engagement between the anchor claws 135 and the stator tube 115 preferably until tension applied on the extraction pin 120 is sufficient to overcome the strength of the shear pin 140, thereby allowing the anchor claws 135 to become disengaged from the stator tube 115. Preferably shear pin 140 is steel, however shear pin 140 can be of another material, such as plastic, nylon, other metals, wood, or other naturally occurring or manmade materials. Continued tension on the extraction pin 120 preferably forces the extraction pin into engagement with an anchor cap 145, which allows the anchor 100 and equipment 105 to be dragged to the surface.

Figure 3 depicts an embodiment of the equipment 105 end of the system. As noted herein, the example equipment 105 depicted is a turbine generator. The turbine generator is merely an example of possible equipment 105 couplable to anchor 100. In the preferred embodiment, drilling fluid 150 flows around anchor 100 (as shown in figure 2) and equipment 105 (as shown in figure 3) and through slots 155 in stator tube 115. While four slots are shown (two on top and two on the bottom) another number of slots can be used, for example two, six, eight, ten, or twelve slots. Slots 155 are preferably oblong in shape, for example slots can be 4 inch by ½ inch. However, slots 155 can have another shape, such as circular or rectangular. Once the fluid 150 passes through slots 155 into the interior of stator tube 115 the fluid may interact with the equipment 105. For example, in the embodiment shown in figure 3, the fluid may rotate a turbine 160 attached to a shaft 165 that drives the turbine generator.

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."