WO2013177165A1

WO2013177165A1 - Method for operating formation measuring instrument using sea floor drilling apparatus

Info

Publication number: WO2013177165A1
Application number: PCT/US2013/042024
Authority: WO
Inventors: Ronald Boggess
Original assignee: Gregg Marine, Inc.
Priority date: 2012-05-23
Filing date: 2013-05-21
Publication date: 2013-11-28

Abstract

A method for drilling and testing formations below the bottom of a body of water includes disposing a drilling system on the bottom of the body of water. The formations are drilled by rotating a drill rod having a latch therein and advancing the drill rod longitudinally. At a selected longitudinal position, an upper end of the drill rod is opened and a cable having a measuring instrument at an end thereof are lowered into the drill rod. The drill rod is lifted to engage the measuring instrument with the latch in the drill rod. The instrument when latched extends beyond a longitudinal end of the drill rod when the latch is engaged.

Description

METHOD FOR OPERATING FORMATION MEASURING INSTRUMENT USING SEA FLOOR DRILLING APPARATUS

Background

[0001] The disclosure relates generally to the field of drilling Earth formations below the bottom of a body of water using remotely operated drilling devices that are positioned on the water bottom. More specifically, the disclosure relates to methods for using formation parameter measuring instruments from such water bottom drilling devices.

[0002] U.S. Patent No. 7,380,614 issued to Williamson et al. describes an example water bottom-deployed drilling apparatus. Such apparatus may be used, for example to obtain core samples of formations at relatively shallow depths below the water bottom. There exists a need for a water bottom based drilling unit that can obtain core samples with reduced tool handling an operating time. A water bottom drilling system according to one aspect of the disclosure in the foregoing patent includes a frame configured to rest on the bottom of a body of water. A support structure is movably coupled to the frame. The support structure is configured to enable at least vertical movement of a drill head mounted on the support structure. A winch is movably coupled to the support structure and configured to enable lateral movement of the winch mounted on the support structure. The winch includes a cable thereon. An end of the cable includes a latching device thereon configured to latch onto an upper end of a core barrel disposed in the lower end of a drill string. A storage area is associated with the frame for drill rods and for core barrels. The core barrels each include a latch configured to releasably engage with a lowermost drill rod on a drill string. Each core barrel includes a latch configured to engage the latching device at the end of the cable. At least one clamp is associated with the frame and is arranged to fix a vertical position of a drill string over a drill hole.

[0003] A method for drilling formations below the bottom of a body of water using the foregoing describe system includes disposing the drilling system on the bottom of the body of water. The formations are drilled by rotating a first drill rod having a first core barrel latched therein and advancing the drill rod longitudinally. At a selected longitudinal position, an upper end of the first drill rod is opened and a cable having a latching device at an end thereof is lowered into the first drill rod. The winch is retracted to retrieve the first core barrel. The first core barrel is laterally displaced from the first drill rod. A second core barrel is inserted into the first drill rod and latched therein. A second drill rod is affixed to the upper end of the first drill rod. Drilling the formation is then resumed by longitudinally advancing and rotating the first and second drill rods. The above procedure may be repeated by opening the upper end of the uppermost drill rod, retrieving the core barrel using the winch, displacing the retrieved core barrel, inserting a new core barrel in the drill string until it latches in the first drill rod, affixing a new drill rod to the upper end of the drill string, and resuming drilling.

[0004] It is also known in the art to use such drilling systems to deploy certain types of formation measuring instruments in order to obtain values of certain physical parameters of the formations below the water bottom, with or without obtaining physical samples of the formations. One such device is known as a cone penetrometer. Cone penetrometer testing (CPT) measurements are related to the total penetration resistance to pushing a tool with a conical tip into the sub-bottom formations. Different methods may be used to separate the total measured resistance into components generated by the conical tip (the "tip friction") and friction generated by the rod string or drill string when CPT is performed using water bottom drilling apparatus.

[0005] What is needed is an improved technique for sub-bottom formation CPT.

Summary

[0006] One aspect of the disclosure relates to a method for drilling and testing formations below the bottom of a body of water, including disposing a drilling system on the bottom of the body of water. The formations are drilled by rotating a drill rod having a latch therein and advancing the drill rod longitudinally. At a selected longitudinal position, an upper end of the drill rod is opened and a cable having a measuring instrument at an end thereof are lowered into the drill rod. The drill rod is lifted to engage the measuring instrument with the latch in the drill rod. The instrument when engaged with the latch extends beyond a longitudinal end of the drill rod when the latch is engaged. The drill rod is lowered until the measuring instrument is moved a selected longitudinal distance. The cable is retracted to release the latch and remove the instrument from the drill rod. Drilling the formation is resumed by closing the upper end of the drill rod and longitudinally advancing and rotating the drill rod.

[0007] Other aspects and advantages will be apparent from the following description and the appended claims.

Brief Description of the Drawings

[0008] FIG. 1 shows a ship deploying a drilling system on the bottom of a body of water.

[0009] FIG. 2 shows a plan view of an example drilling system according to the invention.

[0010] FIG. 3 shows a side view of the drilling system shown in FIG. 2.

[0011] FIG. 4 shows an end view of the drilling system shown in FIG. 2.

[0012] FIGS. 5A through 5H show one example of a drilling method.

[0013] FIG. 6 shows a cut away view of a cone penetrometer instrument disposed in a modified drill rod.

[0014] FIG. 7 shows a side view of the instrument shown in FIG. 6.

[0015] FIG. 8 shows a cross section of the instruments in FIG. 7.

Detailed Description

[0016] FIG. 1 shows an example ship or vessel 2 having a winch 3 or similar spooling device thereon on the surface of a body of water 4 such as the ocean. The winch 3 can spool and unspool a deployment cable 6 and an umbilical cable 34 used to deploy an example water bottom-deployed drilling system 10 on the bottom 11 of the body of water. The deployment cable 6 may nor may not be part of the same physical cable as the umbilical cable 34. The example water bottom based drilling system 10 is deployed using the cable 6 and is caused to rest on the bottom 11 of the body of water. After drilling operations are completed, the system 10 may be retrieved and returned to the vessel 2. In some examples the vessel 2 may include equipment (not shown) for receiving and/or processing signals communicated from and/or supplying power to operate a measuring instrument associated with the drilling system 10 (explained further below).

[0017] A plan view of the example drilling system is shown in FIG. 2. The drilling system 10 may be mounted on a frame 12 that provides support for the various components of the system 10. The frame 12 may have support legs 14 disposed on two corners to maintain the frame 12 in suitable orientation when the system 10 is disposed on the bottom of a body of water. An adjustable height leveling leg 16 may be disposed on the opposite side of the frame. Another possible configuration is that all the legs 14, 16 may be adjustable height. An electrical and hydraulic power unit 30 may accept electrical and/or hydraulic power through the umbilical cable (34 in FIG. 1) that extends from the system 10 to the vessel (2 in FIG. 1) on the water surface. The frame 12 may include one or more features used to lower the system 10 through the water using the winch (3 in FIG. 1) or similar device deployed on the vessel (2 in FIG. 1). Deployment of the system can be similar to that using water bottom deployed drilling systems known in the art, and the manner of deployment of the system 10, and certain features of the system 10 as shown are not intended to limit the scope of the disclosure. Electrical and/or hydraulic power supplied by and through the power unit 30 may operate the various devices disposed on the frame 12 as will be further explained below. The power unit 30 may include a fluid pump (not shown separately) to circulate flushing fluid for drilling operations.

[0018] The frame 12 may include a drill head support structure 18. Such structure may include devices for vertically raising and lowering a drill head (32 in FIG. 3) and for moving the drill head (32 in FIG. 3) laterally along the frame 12 so that the drill head (32 in FIG. 3) may be coupled to a drill string, and may be moved out of the way of the drill string so that certain operations described below may be performed on and within the drill string. [0019] The frame 12 may also support a wireline winch 20. The winch 20 may include a selected length of armored cable (see also 22A in FIG. 5D) on a reel 22. The cable (22A in FIG. 5D) may or may not have one or more insulated electrical conductors therein. The cable (22A in FIG. 5D) may also be slickline, wire rope or synthetic fiber line. The purpose for the winch 20, winch reel and cable will be further explained below with reference to FIGS. 5A through 5H. The cable (22A in FIG. 5D) may include a latch 56 on it end to connect to measuring instruments, as will be further explained, or core barrels. The winch 20 may be mounted on a support structure 23 that enables the winch 20 to be moved laterally along the frame. Either or both support structures 18, 23 may include devices such as hydraulic rams (not shown) to enable lateral movement of the drilling head and the winch, respectively. Other examples of devices to provide lateral movement capability may include a toothed rack and motor driven spur gear. The particular implementation used to laterally move either support structure 18, 23 is not intended to limit the scope of the invention.

[0020] The frame 12 may also include storage area for drill rods 24 and for core barrels

26, respectively. A tool handling gantry 28 may be coupled to the frame 12 and arranged to remove drill rods (see 60 in FIG. 5A) from the storage area 24 or to replace drill rods in the storage area 24. The tool handling gantry 28 may also be arranged to move core barrels (not shown) to and from the storage area. Typically the tool handing gantry 28 will move the drill rods (60 in FIG. 5A) or core barrels (not shown) so that they can be retained by jaws or grippers on a tool handling arm (44 in FIG. 3) that grabs the respective core barrel or drill rod from its outer surface so that the interior of the respective core barrel or drill rod is accessible.

[0021] A side view of the system 10 is shown in FIG. 3. A drill head 32 is shown in its rest position to enable operations within the interior of the drill string. The lower portion of the frame 12 supports an alignment clamp 48, upper foot clamp 50, lower foot clamp 52 and casing clamp 54. The various clamps are used to lock in place elements of the drill string as additional drill rods are added thereto or removed therefrom. The tool handing gantry (28 in FIG. 1) may also include a grabber 42 for oversized drilling tools. The tool handing gantry 28 may also include a handling arm and jaw 44 as explained above. Drilling tools may be stored in a respective tool magazine 46.

[0022] An end view of the system is shown in FIG. 4.

[0023] Having explained the principal components of a water bottom disposed drilling system, a method of operating such system to deploy and retrieve a measuring instrument such as a cone penetrometer tool (CPT) will now be explained with reference to FIGS. 5A through 5H. First referring to FIG. 5A, at the start of drilling operations, an assembly of a drill rod 60 and CPT 62 latched inside the drill rod 60 coupled to the drill head 32 and suspended above the water bottom 11. In some implementations the drill head 32 may include a hydraulically operated motor or electric motor (neither shown separately) to cause rotation of the drill rod 60. The drill head 32 may also include a hydraulic swivel (not shown) to enable pumping of flush fluid through the interior of the drill rod 60 during drilling operations and in particular while the drill rod 60 is being rotated. Other implementations may include a means for rotating the drill rod 60 coupled to the frame proximate one or more of the clamps (see FIG. 3). The manner of rotating the drill rod 60 is left to the discretion of the system designer and is not intended to limit the scope of the disclosure. An annular opening or other type of drill bit 63 may be disposed at the bottom of the drill rod 60 to drill the subsurface formations as the drill string advances downwardly below the water bottom 11. The beginning of such drilling a borehole 13 using the first assembly of drill rod 60 is shown in FIG. 5B.

[0024] In FIG. 5C, the borehole 13 may be drilled such that the first drill rod 60 is moved to the lowermost possible position within the drilling system, and to continue extending the borehole 13 would require lengthening the drill string by coupling to an upper end thereof an additional drill rod 60. The drilling may also be stopped at any intermediate position along the first drill rod or any additional drill rods coupled thereto. In FIG. 5C, the drill string is raised so that the drill rod 60 may be securely locked in the foot clamp 50. The drill head 32 may then be removed from the upper end of the drill rod 60, or a valve (not shown) in the top of the drill head 32 may be opened to enable insertion of the CPT (62 in FIG. 5D) into the interior of the drill rod(s) 60. Such removal may be performed by rotationally locking the drill rod(s) and counter rotating the drill head 32, or by rotationally locking the drill head 32 and rotating the drill rod 60 using a breakout device (not shown) in the foot clamp 50. In other examples, the drill head 32 may include a top drive having a hydraulic chuck (not shown). The manner of making and breaking connections between the drill head 32 and the drill rods 60 and between adjacent interconnected drill rods 60 is not intended to limit the scope of the disclosure. After the drill head 32 is uncoupled from the drill rod 60, the drill head 32 may be laterally repositioned using, for example, the device shown at 18 in FIG. 1, or the drill head 32 may be opened at the top as explained above. Laterally repositioning the drill head 32 enables more easily moving devices inside the drill rod 60 and/or coupling additional drill rods to the drill rod 60 partially disposed in the borehole 13. When one or more additional drill rods are coupled to the drill rod 60 disposed in the borehole 13, the assembly is referred to as a "drill string." As a different approach than lateral repositioning, the drill head 32 may be moved longitudinally to a height above the upper end of the drill rod 60 sufficient to enable moving the winch over the drill rod to provide access by the cable (on the winch reel 22) to the interior of the drill rod 60.

[0025] Then the winch reel 22 may be operated to lift and move the CPT 62 into position over the top drive or open drill rods. The winch reel 22 extends a cable 22 A to lower the CPT 62 and a latch (see FIGS. 6 and 7) down into the drill string (or wellbore casing, not shown) The CPT 62 maybe lowered into the drill rods 60 while raising the drill rods 60 so that at least part of the CPT 62 extends below the drill rods 60 (or casing). The CPT 62 may continue to be lowered until a latch at a selected position thereon, e.g., at the uppermost end, is engaged in the drill rods 60 (or casing). The CPT 62 in some examples may be pumped to the bottom of the drill rod 60 and latched into position in the drill rod 60. Such pumping may include the use of, e.g., a side entry sub for the cable 22A that may be coupled to the upper end of the open drill string.

[0026] Baseline measurements from the CPT 62 may then be made.

[0027] The CPT 62 may then be pushed downwardly using the drill rods 60 (or casing) at a substantially constant rate until additional movement stops, or to the end of the "stroke" (the length to which the CPT 62 extends past the end of the bit 13) while continuing to make measurements.

[0028] The CPT 62 may be unlatched by pulling up on the cable (22A in FIG. 5C). The

CPT 62 may be replaced into a holding station, the top drive valve closed (or the drill head 32 reconnected) and drilling may resume.

[0029] In, more detail with reference to the above procedure, in FIG. 5D, the winch 22 may be laterally repositioned such that an end of the cable 22A with the CPT 62 attached is disposed directly above the open upper end of the drill rod 60 locked in the foot clamp 50. The winch reel 22 is then operated such that a latch of any type known in the art is lowered into the interior of the drill rod 60 and is then latched to a mating feature (FIG. 7) in the upper end of the CPT 62, as shown in FIG. 5E. After the above described movement of the drill rod(s) and making measurements, the CPT 62 may then be removed from the interior of the drill rod 60 by unlatching by the action of the latch 56 and operating the winch reel 22 to retract the cable 22A and CPT 62 from the inside of the drill rod(s) 60. The winch reel 22 may then be laterally repositioned such that the CPT 62 previously retrieved from the inside of the drill rod 60 may moved to be stored in the storage area (26 in FIG. 1).

[0030] The CPT 62 may be repeatedly retrieved from the storage area (26 in FIG. 2) and inserted in the drill rod 60 still in the borehole 13 as required for any one or more drill rods in the manner explained above with reference to FIGS. 5D and 5E.

[0031] In FIG. 5F, an additional drill rod 60 may be coupled to the drill head 32, and the drill head 32 lowered so that the additional drill rod 60 is affixed to the drill rod 60 still locked in the foot clamp 50. The foot clamp 50 may then be released, and as shown in FIG. 5G, drilling may resume by rotating and longitudinally advancing the drill string. Drilling continues typically until the uppermost drill rod reaches the lowest possible position in the system, as shown in FIG. 5H. At such time, the procedure explained with reference to FIGS. 5D and 5E can be repeated, and drilling may continue for each successive additional drill rod coupled to the drill string until the borehole 13 is extended to the intended depth. [0032] By retrieving the CPT 62 from the lowermost drill rod 60 using the wireline latch

56 as explained above, successive CPT tests may be performed in the borehole 13 without the need to retrieve the entire drill string each time a CPT test is performed. Such capability substantially reduces the number of tool operations and amount of time needed to drill a borehole below the bottom of a body of water.

[0033] A cut away view of a drill rod 60 having a CPT 62 therein is shown in FIG. 6 and

FIG. 7. The CPT 62 may include a fishing neck 64 (FIG. 7) configured to engage the overshot (56 in FIG. 2). The CPT 62 may include a latch 68 that can be released by the upward force exerted by the cable (22A in FIG. 5C) when the CPT 62 is to be retrieved from the drill rod 60. A shoulder (not shown) inside the drill rod 60 may provide a seat to retain the CPT 62 when it is lowered or pumped into the drill rod 60. The drill rod 60 may be modified 60 A to include an adapter coupling 60B and a locking coupling 60C, while the CPT 62 may include a cone assembly 60A, friction reducer 60B and cone rod 60C. A cross section view is shown in the latch area in FIG. 8.

[0034] Referring once again to FIGS. 5D and 5E, in some examples, the cable 22A may include one or more electrical conductors and/or optical fibers. The winch 22 drum may include slip rings to enable rotation of the winch drum 22 while maintaining electrical and/or optical continuity between the CPT 62 and a fixed cable end of the slip rings. The fixed cable end may be electrically or optically connected to the umbilical cable (34 in FIG 1) so that signals generated by the CPT 62 may be sent to the surface in real time (e.g., including delay resulting from signal processing and/or transmission time). In some examples, electrical power to operate the CPT 62 may be supplied from the surface through the umbilical 34, which may be electrically connected to the fixed end of the slip rings on the winch drum 22.

[0035] The scope of the present disclosure is not limited to cone penetrometers. In other non-limiting examples, the measuring instrument, of which the CPT is only one example, may be a pressure gauge or transducer, a temperature sensor, a thermal conductivity sensor, an acoustic compressional and/or shear wave velocity sensor and an electrical resistivity sensor. The foregoing is not an exhaustive list of the types of measuring instruments that may be operated as explained with reference to FIG. 5D and 5E. While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.

Claims

Claims What is claimed is:

1. A method for drilling and testing formations below the bottom of a body of water, comprising:

disposing a drilling system on the bottom of the body of water;

drilling the formations by rotating a drill rod having a latch therein and advancing the drill rod longitudinally;

with the drill rod at a selected longitudinal position, opening an upper end of the drill rod and lowering a cable having a measuring instrument at an end thereof into the drill rod;

lifting the drill rod to engage the measuring instrument with the latch in the drill rod, the instrument when engaged with the latch extending beyond a longitudinal end of the drill rod when the latch is engaged;

lowering the drill rod until the measuring instrument is moved a selected longitudinal distance;

retracting the cable to release the latch and removing the instrument from the drill rod; and

resuming drilling the formation by closing the upper end of the drill rod and longitudinally advancing and rotating the drill rod.

2. The method of claim 1 wherein the measuring instrument comprises a cone penetrometer.

3. The method of claim 1 wherein the measuring instrument comprises at least one of a pressure gauge or pressure transducer, a temperature sensor, a thermal conductivity sensor, an acoustic compressional and/or shear wave velocity sensor and an electrical resistivity sensor.

4. The method of claim 1 wherein the rotating comprises operating a motor in a drill head coupled to the drill rod.

5. The method of claim 1 wherein the opening the upper end of the drill rod comprises removing a drill head therefrom.

6. The method of claim 5 wherein the removing the drill head further comprises displacing the drill head at least one of vertically and laterally a sufficient amount to enable access to the interior of the first drill rod by the cable.

7. The method of claim 5 further comprising lifting the drill rod from a bottom of a borehole created by drilling, and affixing a longitudinal position of the drill rod prior to opening the upper end thereof.

8. The method of claim 1 wherein the opening the upper end of the drill rod comprises opening a valve in a top drive.

9. The method of claim 1 further comprising communicating measurements made by the measuring instrument to the surface substantially in real time.

10. The method of claim 1 further comprising attaching at least one additional drill rod to the upper end of the drill rod advanced into the formations prior to resuming drilling.