WO2000060212A1

WO2000060212A1 - Pipe conveyed logging system and method

Info

Publication number: WO2000060212A1
Application number: PCT/US2000/008663
Authority: WO
Inventors: Glen Larry Nimegeers; Blair Ross Macdougall
Original assignee: Baker Hughes Incorporated
Priority date: 1999-04-01
Filing date: 2000-03-31
Publication date: 2000-10-12

Abstract

A system and method for increasing the depth of pipe conveyed logging operations. A wireline is installed within a tubular to transmit electric power and signals between a downhole logging tool and the well surface. The wireline can be supported midway along its length to reduce the strain acting on each wireline section, or can be installed in two or more connected sections. Each wireline connection can be supported with a landing sub attached to the tubular for independently carrying the weight of the wireline section below the landing sub.

Description

PIPE CONVEYED LOGGING SYSTEM AND METHOD

BACKGROUND OF THE INVENTION The invention relates to the field of pipe conveyed logging downhole in a wellbore. More particularly, the invention relates to an improved system and method for running a wireline logging tool in deep or extended length wellbores.

Logging tools are run in wellbores to evaluate subsurface geologic formations. Logging tools are lowered on the lower ends of cables or wirelines which transmit electric power between the wellbore surface and the downhole logging tool. The wirelines also transmit signals between the logging tool and control equipment located at the wellbore surface. Logging equipment is typically raised and lowered by reeling in or paying out the wireline from a rotatable storage drum. Horizontal drilling and production techniques and the desire to produce hydrocarbons from deeper formations exceed existing wireline capabilities. In deeper wellbores, the combined weight of the logging tool and elongated wireline strain the wireline near the wellbore surface at the maximum point of wireline stress. Mechanical "tractors" have been developed to transport electrical conductors horizontally into wells, however such devices are expensive and subject to mechanical failure. To log deep or extended wellbores, tubulars such as coiled tubing or drill pipe transport logging tools into the wellbore. A wireline is installed within the coiled tubing or drill pipe to provide electrical communication between the downhole logging tool and the wellbore surface. Tubing and drill pipe support the logging equipment weight and are also useful for pushing logging equipment through deviated and horizontal wellbores. Coiled tubing is relatively more expensive to deploy than are tubulars such as drill pipe strings formed with individual pipe sections.

Many conventional logging systems have been developed for downhole wellbore logging. United States Patent Nos. 4,064,939 and 4,082,144 to Marquis (1978) disclosed a method and apparatus for running logging instruments in highly deviated wellbores. Open-ended drill pipe was positioned in the wellbore and a semi-rigid extension formed with multiple sections was attached to a logging cable. A catcher sub at the drill pipe lower end prevented the semi-rigid extension from being pumped out of the drill pipe. Another extension member was disclosed in United States Patent No. 4,337,969 to Escaron et al. (1982) wherein a rigid extension protected a well logging cable.

United States Patent No. 4,457,370 to Wittrisch (1984) also disclosed a method and device for logging in highly deviated wellbores. A tool was attached to the lower end of a drill string, and a female connector and attached cable end was pumped downwardly into engagement with a male connector attached to the downhole tool.

United States Patent No. 4,799,546 to Hensley et al. (1989) disclosed a drill pipe conveyed logging system suitable for use in a highly deviated wellbore. A male wet connector was attached to the logging tool, and a female wet connector was attached to a logging cable. The logging cable was pumped down into the wellbore until the female and male wet connectors established electrical communication between the logging tool and surface. A weight was attached to the logging tool to maintain the orientation of the logging tool relative to vertical.

Other tools have been developed to facilitate coiled tubing or drill pipe conveyed logging. United States Patent No. 4,603,578 to Stoltz (1986) disclosed a side entry tub having a tension release wireline clamp. United States Patent No 4,20,297 to Tricon (1980) disclosed a side entry clamp which permitted drilling mud to be pumped through the drill stem. United States Patent Nos. 4,678,038, 4,884,632 and 4,884,632 to Rankin (1989) disclosed a side entry sub logging system permitting cable removal if the drill pipe became stuck in the wellbore. United States Patent Nos. 4,913,227 and 5,080,168 to Wittrisch (1992) disclosed other devices for anchoring a cable through a side-entry sub. United States Patent No. 5,389,003 to Van Steenwyk et al. (1995) disclosed a wireline wet connection, and United States Patent No. 5,642,780 to Moore (1997) disclosed an electrical connection stand-off.

In another well logging related invention, United States Patent No. 5,477,921 to Tollefsen (1995) disclosed a method for well logging as a stuck logging tool was located and retrieved from the wellbore. Communication with the stuck logging tool was re-established by attaching electrical conductors to a severed cable so that well logging could continue during fishing operations. Although the depth of well logging operations is extended by pipe conveyed techniques, the operable logging depth is limited by the wireline weight within the pipe. Wireline lengths greater than 8,000 meters are difficult to accomplish with existing wireline technology because wireline stretch begins at approximately fifty percent of the wireline breaking strength. In wellbores or in long horizontal wellbores, wireline damage occurs from factors such as drum crush as the wireline is wound on a storage drum. Wireline damage also occurs because the wireline is physically unable to support the increased loads in deep logging operations. In addition to the wireline tension during normal operations, additional wireline tension is added if the drillpipe becomes stuck in the wellbore. Retrieval of the wireline typically requires additional tension to release the lower attachment from the logging tool or from snags within the tubular, and this additional stress can cause wireline failure.

As the depth and length of wellbores increase, a new logging system and technique is necessary to permit wellbore logging in horizontal and deep wellbores. Preferably, a deep logging system and technique should be operable without significantly increasing the cost of wellbore logging operations. SUMMARY OF THE INVENTION The invention provides an improved method and system for logging a wellbore. The method comprises the steps of attaching a logging tool to a lower end of a hollow tubular, lowering the tubular lower end and the logging tool into the wellbore, and positioning a first wireline section through said tubular so that a lower end of the first wireline section is attached to the logging tool and an upper end of the first wireline section is stationary relative to the tubular. A second wireline section is positioned into the tubular interior while retaining an upper end of the second wireline section at the wellbore surface, and the second wireline section is connected to the first wireline section to establish electrical communication between the logging tool and the wellbore surface. In other embodiments of the invention, the first and second wireline sections can be joined with a means for attaching wireline to the tubing interior at a selected location to independently support the first wireline section weight.

The system of the invention comprises a hollow tubular having a lower end positionable into the wellbore, a logging tool attached to the tubular lower end, a first wireline section having a lower end for attachment to the logging tool and having an upper end stationary relative to the tubular, and a second wireline section for attachment to the first wireline section to establish electrical communication between the logging tool and the wellbore surface. In different embodiments of the invention the tubular can comprise drill pipe or coiled tubing. ln another embodiment, the wireline can comprise a single cable length, and an attachment means can engage the tubular to support the lower wireline section.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates a logging tool engaged with a wireline formed with two or more sections. Figures 2 and 3 illustrate a combination of wet connector and loading sub.

Figure 4 illustrates a single wire attachable to the tubular interior with an engagement tool.

Figure 5 illustrates a wireline entry guide for facilitating pumping of a latch through a tubing interior.

Figure 6 and 7 illustrate attachment of the first wireline section to the second wireline section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention provides a method and system for wireline logging operations in deep or extended length wellbores. Figure 1 illustrates one embodiment of the invention wherein wellbore 10 is located in geologic formations 12. Logging tool 14 is attached to tubular 16 formed with a plurality of drill pipe sections, coiled tubing, or other tubular or other shaped structure having a hollow interior and deployable downhole in wellbore 10. Although logging tool 14 is described as a single device, logging tool 14 can comprise multiple devices performing different functions. Each component of logging tool 14 can be located together in a single housing or in different housings placed proximate to each other or located at a selected distance from the other components.

Tubular 16 can comprise a drill string or other conventional device for positioning logging tool 14 downhole in wellbore 10 and can provide a structure for circulating fluids inside or outside of tubular 16. For example, drilling fluid can be pumped through tubular 16 to lubricate tubular 16 and to provide well control and other capabilities. Tubular 16 has the capability to push logging tool 14 through undergauge or horizontal parts of wellbore 10 where pipe sticking can occur. Although Figure 1 illustrates wellbore 10 in a substantially vertical orientation, the invention is particularly suited to highly deviated or horizontal single or multi-branch wellbores.

As shown in Figure 1 , wireline 20 is comprised of first wireline section 22 and second wireline section 24. First wireline section 22 has lower end 26 and upper end 28. The descriptions of "upper" and "lower" are for reference in the invention embodiment shown in Figure 1 and will inherently vary for wellbores which are horizontal or which slope upwardly through geologic formations 12. Lower end 26 is engaged with wet connector 30 for attaching first wireline section 22 to logging tool 14 and for providing electrical connection therebetween. Upper end 28 is held in a position stationary relative to tubular 16 with loading sub 32. Sub 32 can be landed in a recess within the interior of tubular 16, can be landed within a pin box of an individual pipe section within tubular 16, or can be attached to the interior wall of tubular 16 with various mechanical or hydraulic devices.

Loading sub 32 is positioned at a selected position within tubular 14 to control the stress acting on first wireline section 24. In a substantially vertical well as shown, the maximum stress acting on first wireline section 22 will be at upper end 28. By shortening the required length of first wireline section 22 and by fixing upper end 28 stationary relative to tubular 16, the maximum stress acting on first wireline section 22 is reduced. Upper end 28 is attached to wet connector 34 for establishing an electrical connection with second wireline section 24. Lower end 36 of second wireline section 24 is attached to wet connector 34, and upper end 38 of second wireline section 24 is engaged with spool 40 at the wellbore surface. Pulleys 42 redirect second wireline section 24 from a vertical orientation to engagement with spool 40.

Second wireline section 24 is installed into the interior of tubular 16 through side entry sub 44 attached to tubular 16. Side entry sub 44 permits movement of wireline 20 therethrough while providing seals to contain fluids pumped through the interior of tubular 16. Figures 2 and 3 illustrate one embodiment of loading sub 32 having body 46 and aperture 48 for permitting engagement with wet connector 34 and the internal conductors linking first wireline section 22 and second wireline section 24. Figure 3 shows the relationship of wet connector 34 with loading sub 32. Ports 50 permit pressure equalization and passage of fluid between adjacent portions of tubular 16. Surface 52 is landed against box surface 52 within a drill pipe section of tubular 16, and this contact provides the structural connection to support wet connector 34 and first wireline section 22. Shear pins 54 temporarily attach loading sub 32 to tubular 16 and can be sheared to release loading sub 34 from a stationary position relative to tubular 16 when pulled upwardly as described below.

Figure 4 illustrates another embodiment of the invention wherein a single wireline 54 is installed between logging tool 14 and the wellbore surface. Tubular engagement tool 56 is attached to wireline 54 and is located at a selected position between logging tool 14 and the wellbore surface. Engagement tool 56 grips wireline 54 and an interior wall or discontinuity within tubular 16. Engagement tool 56 can be landed within a recess or protrusion within tubular 16 or can be moveably actuated with hydraulic or electric setting mechanisms to grasp the interior wall of tubular 16. For a hydraulic operated mechanism, a separate hydraulic control line can run from the wellbore surface to engagement tool 56, of the pressure of fluid within tubular 16 can be increased or decreased as a single event or event cycle to operate engagement tool 56.

After a lower or distal end of wireline 54 has been lowered into engagement with logging tool 14, engagement tool 56 can be landed or otherwise actuated to fix the attached portion of wireline 54 stationary relative to tubular 16. In this manner the tension acting on wireline 54 below engagement tool 56 can be controlled by the selected placement of engagement tool 56 relative to tubular 16 and logging tool 14. The tension acting on the upper portion of wireline 54 above engagement tool 56 can be controlled from the wellbore surface.

The method of the invention can be performed in different ways to accomplish the objective of reducing the tension acting a logging tool supported wireline. Figure 5 shows logging tool 14 attached to tubular 16 downhole in wellbore 10. Wireline lower end 26 can be run into tubular 16 with a bottom sinkerbar (not shown), fluid pumping techniques, or other conventional procedures. To pump lower end 26 into tubular 16, wireline entry guide 58 is attached to wireline lower end 26, and fins 60 are attached to an exterior surface of entry guide 58. Fins 60 provide the dual purposes of centralizing entry guide and lower end 26 within the interior of tubular 16, and also act as pistons within tubular 16 when acted upon by a pressurized fluid within tubular 16. By pumping a fluid downwardly into tubular 16, fins 60 push entry guide 58 downwardly until wireline lower end 26 engages wet connector 30. The upper end of entry guide 58 can have notched neck 62 for facilitating fishing operations in the event of wireline separation or other damage.

Figures 6 and 7 illustrate attachment of first wireline section 22 to second wireline section 24. The length of first wireline section 22 is consistent with the initial length of tubular 16 run into wellbore 10 and can be selected to control the amount or slack or absence of slack within tubular 16. Pin box 64 is retained in slips 66 and upper end 28 is supported with loading sub 32. Second wireline section 24 is run through side entry sub 44 and wet connector 34 attaches wireline first section 22 to wireline second section 24. Side entry sub 32 can be attached to pin box 64 and the assembly can be lowered into wellbore 10.

To remove wireline 20 from tubular 16, spool 40 can be rotated to draw second wireline section 24 into tension until shear pins 54 are sheared. This pemits the lower end of second wireline section 24 and wet connector 34 to be drawn upwardly and out of the tubular 16 interior. Alternatively, the lower end of either first wireline section 22 or the lower end of second wireline section 24 can be removed with a pressure actuated connection such as wet connector 30 which unlatches when the fluid pressure within tubular 16 is increased or decreased to a certain level or in a certain pattern. Tubular 16 can be raised in wellbore 10 until upper end 28 is retrievable at the wellbore surface. By tensioning upper end 28, a shear pin associated with wet connector 30 can be sheared to permit complete retrieval of wireline first section 22 from the interior of tubular 16, or a shear pin can be associated with wet connector 34 to permit removal of second wireline section 24 independently of first wireline section 22. In this manner, wireline 20 can be selectively dissembled as an integral unit or in individual sections.

The invention uniquely isolates wireline 20 from stresses experienced in supporting the entire wireline length within wellbore 10. Separate wireline sections can be linked and supported to form an integral wireline system, or a single wireline length can be attached at a mid point location within tubular 16 to isolate the lower wireline section below the attachment tool. By isolating the tension acting on each wireline section in combination with a tubular supported logging tool, extraordinary wireline logging depths can be efficiently reached without significantly increasing logging costs or interference with logging and other wellbore operations. Although the invention has been described in terms of certain preferred embodiments, it will be apparent to those of ordinary skill in the art that modifications and improvements can be made to the inventive concepts herein without departing from the scope of the invention. The embodiments shown herein are merely illustrative of the inventive concepts and should not be interpreted as limiting the scope of the invention.

Claims

WE CLAIM:

1. A method for logging a wellbore, comprising the steps of: attaching a logging tool to a lower end of a hollow tubular; lowering said tubular lower end and said logging tool into the wellbore; positioning a first wireline section through said tubular so that a lower end of said first wireline section is attached to said logging tool and an upper end of said first wireline section is stationary relative to said tubular; lowering a second wireline section into said tubular interior while retaining an upper end of said second wireline section at the wellbore surface; and connecting said second wireline section to said first wireline section to establish electrical communication between said logging tool and the wellbore surface.

2. A method as recited in Claim 1 , wherein said tubular comprises a plurality of pipe sections, further comprising the step of lengthening said tubular by attaching additional pipe sections.

3. A method as recited in Claim 1 , further comprising the steps of attaching a wireline side entry sub to said tubular and of positioning said second wireline section through said side entry sub.

4. A method as recited in Claim 1 , further comprising the step of operating said logging tool.

5. A method as recited in Claim 1 , further comprising the step of positioning said first wireline section within said tubular after said logging tool is lowered into the wellbore.

6. A method as recited in Claim 1 , further comprising the step of attaching the second end of said first wireline section to said tubular.

7. A method as recited in Claim 1 , further comprising the step of attaching a landing sub to said tubular, and of attaching the second end of said first wireline section to said landing sub.

8. A method as recited in Claim 1 , further comprising the step of positioning said first wireline section into said tubular by pumping a fluid to transport said first wireline section through said tubular.

9. A method as recited in Claim 8, further comprising the step of discharging said fluid through an aperture in said tubular located proximate to said logging tool.

10. A method as recited in Claim 1 , further comprising the step of attaching a third wireline section to said second wireline section.

11. A method as recited in Claim 1 , further comprising the steps of removing said first and second wireline sections from said tubing interior and of removing said tubular from the wellbore.

12. A method for logging a wellbore, comprising the steps of: attaching a logging tool to a lower end of a hollow tubular defining a tubular interior; lowering said tubular lower end and said logging tool into the wellbore; positioning a wireline through said tubular so that a lower end of said wireline is connected to said logging tool and an upper end of said wireline is retained at the wellbore surface; engaging an attachment tool to said wireline and to said tubular support the weight of said wireline below said attachment tool; and lowering said logging tool into the wellbore by extending the length of said tubular and of said wireline between said attachment tool and the wellbore surface.

13. A method as recited in Claim 12, further comprising the step of removing said attachment tool from engagement with said tubular, and of disconnecting the lower end of said wireline from said logging tool, to pemit removal of said wireline from said tubular interior.

14. A system for logging a wellbore, comprising: a hollow tubular having a lower end positionable into the wellbore; a logging tool attached to said tubular lower end; a first wireline section having a lower end for attachment to said logging tool and having an upper end stationary relative to said tubular; a second wireline section for attachment to said first wireline section to establish electrical communication between said logging tool and the wellbore surface.

15. A system as recited in Claim 14, further comprising a controller located at the wellbore surface and attached to said second wireline section for communicating with said logging tool.

16. A system as recited in Claim 14, further comprising a landing sub attached to said tubular for retaining the first wireline section upper end stationary relative to said tubular. 92

93 -17-

94 17. A system as recited in Claim 14, further comprising a pump for

95 pumping a fluid through said tubular for moving said first wireline section into

96 attachment with said logging tool. 97

98 18. A system as recited in Claim 14, further comprising means engaged

99 with said tubular for moving said tubular in said wellbore. 100

101 19. A system as recited in Clam 14, further comprising a wet connector

102 for attaching said first wireline section lower end to said logging tool. 103

104 20. A system as recited in Claim 14, further comprising means for

105 disconnecting said first wireline section from said logging tool. 106

107 108