APPARATUS AND METHOD FOR MOVING TOOLS IN A NONFLOW ENVIRONMENT

SUMMARY

[0001]The present invention is directed to a system for moving a well service tool through a non-flow environment in an underground wellbore. The system comprises a first tool. The first tool comprises a housing, a prime driver, a motor, and a connection point. The prime driver is configured to propel the housing in a fluid. The motor powers the prime driver and is disposed within the housing. The connection point is disposed on the housing for connecting the first tool to the well service tool.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002]FIG. 1 is a side view of a well bore. A thruster is disposed within the bore in a horizontal section. It should be understood that the well bore is not to scale, and dimensions are enlarged or reduced for clarity.

[0003]FIG. 2 is a side view of a thruster within a sectioned conduit. The thruster has one section and is disposed uphole of a service tool.

[0004]FIG. 3 is a side view of an alternative thruster within a sectioned conduit. The thruster has two sections and is disposed uphole of a service tool.

[0005]FIG. 4 is a partially sectional perspective view of the thruster of FIG. 2. The housing is sectioned so that internal components are visible.

[0006]FIG. 5 is a side sectional view of the thruster of FIG. 2.

[0007]FIG. 6 is a close-up view of detail 5 from FIG. 5.

DETAILED DESCRIPTION

[0008]The increased use and development of horizontal drilling in exploratory wells for oil, gas, or other natural resources in recent years has presented new problems. There may be times during the drilling, completion, or production phase of a well that fluid flow is lost within the drill pipe and/or casing. That is, that no fluid can be pumped downhole. Any attempt to add additional fluid beyond that already in the drill pipe or casing just increases the pressure in the conduit. Such a condition is called a “non-flow environment.”

[0009]With reference to FIGS. 1 and 2, in traditional vertical wells, service tools can be introduced at the well head and gravity will cause the service tool to drop to the blockage. Once the service tool reaches the blockage it may be manipulated to clear the blockage or sever the conduit if necessary. In a horizontal well, such as well 100, if the blockage 110 is in the horizontal section 102 of the well 100, the service tool will only drop to the transition point 104 between the vertical 101 and horizontal 102 section of the well 100 and stop. While the conduit could be severed at this transition point 104 it would be very expensive to abandon the horizontal component of the well. A solution is needed to be able to move service tools, such as the service tool indicated by reference number 150 in FIGS. 2 and 3, in the horizontal section 102 to the point of flow blockage 110.

[0010]Referring specifically to FIGS. 2 and 3, a horizontal section 102 of a well 100 with lost fluid flow is shown. The horizontal section 102 of the well 100 comprises a conduit 201 that has an uphole end 202, and a downhole end 203. The conduit 201 may be drill pipe, casing, or the bore wall. Fluid flow is intended to travel from the uphole end 202 to the downhole end 203 during normal operating procedures. In this scenario, however, a blockage 110 exists, preventing flow required for pumping service tools 150 through the well 100, resulting in the nonflow environment of the conduit 201.

[0011]To regain fluid flow in the well 100 the blockage 110 must be cleared. To clear the blockage 110 a service tool 150 must be conveyed to the blockage site and activated or manipulated to clear the blockage. In this scenario the service tool 150 shown is a TENAX Energy Solutions HydraPerf tool but may be any tool used to remove a blockage 110. In addition, a severing tool or the like may be used to deliver a charge to a location in such a non-flow environment.

[0012]The horizontal orientation of the conduit 201 eliminates the gravitational force that would convey the service tool 150 to a blockage in a vertical section 101 of the well. Thus, there is a need to move the service tool 150 in an environment with no flow.

[0013]This disclosure therefore provides a thruster apparatus 300 and method for conveying, or moving, the service tool 150 in the horizontal section 102 of the well 100. The thruster 300 comprises a mechanical power source 302, such as a motor, connected to a thrust generator 304 by a shaft 306, a housing 308, an uphole end 310, and a downhole end 311. A plurality of thrusters 300 may be placed in series to multiply the thrust force applied to the service tool 150. In FIG. 3 there are two thrusters 300 which operate in unison. In FIGS. 2, 4 and 5, there is one thruster 300. As shown in FIGS. 3 and 6, the thruster 300 has a substantially constant diameter from its downhole end 311 to its uphole end 310. Changes in diameter are associated with the ingestion of material within a borehole which may tend to damage the thruster 300 or cause the tool itself to drag.

[0014]Each thruster 300 takes in fluid through a set of downhole slots 320, as shown by arrows 313, and expels the fluid at the uphole end 310, as shown by arrows 314. The expulsion of the fluid in the uphole direction provides a thrust force in the downhole direction. As shown in FIGS. 3 and 6, the slots 320 each open in a radial direction only - that is, through an opening in the thruster 300 which has only a radial component, facing away from a centerline of the thruster. The slots 320, both uphole and downhole of propulsion elements, are parallel to the centerline of the thruster 300. Therefore, the housing has a uniform diameter along the axial lengths of the slots 320, and each slot 32 is entirely on the surface of the housing such that every point of the opening is the same radial distance from a longitudinal axis of the thruster housing 308.

[0015]In operation, once it is determined that a nonflow situation exists, a service tool 150 is placed in the conduit 201 at the well head. After placing the service tool 150 in the conduit 201 at least one thruster 300 is placed behind, or uphole of, the service tool 150. Alternatively, the at least one thruster 300 may be placed in front of the service tool 150, such that the at least one thruster 300 tows the service tool 150. Motor 302 speed, impeller or other thrust generator 304 direction and motor activation may be controlled by controls 330, which may include switches and/or potentiometers and other controls. As shown, the controls are located in the nose at the downhole end 311 of the thruster 300, but other locations are anticipated.

[0016]The service tool 150 will drop in the vertical section 101 of the well 100 until it encounters the horizontal section 102. At this point, when the thruster 300 is behind the tool 150, the downhole end 311 of the thruster 300 will engage the uphole end of the service tool 150 and push the service tool 150 further downhole in the horizontal section 102 until the service tool 150 encounters the blockage 110. Once the service tool 150 encounters the blockage 110 the service tool 150 and the thruster 300 will stop moving and the service tool 150 may be activated by timer, pressure, electrical signal, or other external stimulation.

[0017]In this embodiment the electric motor 302 is powered by a battery 307 but it is contemplated that the electric motor 302 may be powered by an electrical connection to the well head, that is a wireline. Also, in this embodiment the thrust generator 304 is an impeller located in the housing 308. It is contemplated that the thrust generator 304 may be any apparatus that will generate a force when powered by a shaft 306 and supplied with fluid. For instance, it is contemplated that the orientation of the thruster 300 be reversed and the thrust generator 304 be a propeller located outside the housing 308. Further, this embodiment shows a shaft 306 of a given length. It is contemplated that the length of the shaft 306 may vary or that the shaft 306 may be eliminated by connecting the thrust generator 304 directly to the power source 302.

[0018]In smaller conduits 201, such as coiled tubing, the thrusters 300 may be smaller but more thrusters 300 may be used to provide the thrust necessary to move the service tool 150. Thrust generator 304 components may rotate in opposite directions, right or left, to counteract torsional forces imparted to the thruster 300 by the rotation of the thrust generator 304 if necessary. In one embodiment the thruster 300 will continue to provide thrust until the battery 307 is exhausted. It is assumed that by the time the battery 307 is exhausted the service tool 150 will be located at the blockage 110. Activation of the service tool 150 may be delayed until the battery 307 is exhausted to be sure that the service tool 150 is as far downhole as possible. Battery life is easily determined by the size of the battery 307 and motor 302. Alternatively, sensors may be disposed onboard the thruster 300 to stop the thrust generator 304 when a blockage is detected, or a particular portion of the pipeline conduit 201 is detected.

[0019]While this is discussed with reference to a horizontal section 102 of a well 100, the conduit 201 may be a pipeline as well. Pipelines are susceptible to blockages 110 reducing or eliminating flow conditions for the same reason as well bores.

[0020]In another embodiment the thruster 300 may include a wheel disposed through one or more slot 320 formed in the housing 308. One wheel could be capable of propelling the service tool 150 to a blockage, such that a sensor, such as a pressure sensor or other device, detects that the blockage has been abutted by the service tool. The wheels may be powered by the motor or motors 302 disposed within the housing and powered by the batteries 307.

[0021]Alternatively, multiple wheels could be disposed about a circumference of the cylindrical housing 308 of the thruster 300. In either case, it may be advantageous to provide a centering device, such as a steel bow centralizer, a rigid blade, bogey wheel or roller centralizers, flared cup centralizers, arms formed of wire, and the like.

[0022]The various features and alternative details of construction of the apparatuses described herein for the practice of the present technology will readily occur to the skilled artisan in view of the foregoing discussion. It is to be understood that even though numerous characteristics and advantages of various embodiments of the present technology have been set forth in the foregoing description, together with details of the structure and function of various embodiments of the technology, this detailed description is illustrative only, and changes may be made in detail. Changes may especially be made in matters of structure and arrangements of parts within the principles of the present technology to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.