The present invention relates to apparatus for handling pipe used in well drilling and servicing operations, particularly in association with inclined or “slant” wells.
Oil and gas wells are typically drilled by rotating a drill bit mounted to the bottom of a “drill string” made up of sections of pipe (also referred to as “joints” or “tubulars”) joined together by means of threaded connections at the ends of each pipe section. After a well has been drilled, the drill string is removed and typically a string of tubular casing sections is installed to line the wellbore, and then a string of production tubing is inserted into the well to carry oil and gas from a subsurface formation up to ground surface. The term “tripping” is commonly used to describe the procedure of adding a tubular to the drill string or production string (“tripping in”) or removing a tubular from the string (“tripping out”). Well drilling and well servicing involve both tripping in and tripping out, for various purposes well known in the field. During tripping operations, tubulars removed from a drill string or production string must be transported to a pipe storage rack of some sort, and/or from the storage rack to the wellbore for connection to the string already in the wellbore.
There are many known types of apparatus well-suited for carrying out these pipe-handling tasks in association with vertical or near-vertical wells. However, pipe handling is more complicated for tripping operations relating to slant wells, in which the drill string or production string may enter the wellbore at up to 45 degrees or more from vertical.
U.S. Pat. No. 4,951,759 (Richardson) illustrates some of the challenges associated with tripping pipe oil a slant well, including safety issues associated with the handling of heavy joints of pipe. In accordance with conventional methods, handling tubulars usually requires a person to work on an elevated platform in the mast of the drilling rig or service rig, and to connect a winch line to each tubular as it is tripped out of the well so that it can be moved to a vertical suspended position and then swung away from the mast and into a storage rack. Richardson addresses these requirements with a mast-mounted device that can grasp a tubular while inclined parallel to the mast, and then rotate it away from the mast and deposit in on a horizontal storage rack. The mast-mounted pipe-handling device of Richardson must be either installed on a purpose-built rig where the device is accommodated into the design, or retrofitted to an existing rig, which would entail extensive and expensive modifications.
Accordingly, there remains a need for improved pipe handling apparatus, particularly for use in drilling and servicing slant wells. More particularly, there is a need for such improved apparatus that is readily usable with conventional drilling rigs and service rigs, without need for significant or any modification to the rigs. The present invention is directed to these needs.
In general terms, the apparatus of the present invention is a pipe handling unit comprising a pipe manipulation mechanism mounted to a mobile pipe storage rack, which can be parked adjacent to a drilling rig or service rig and which can pick up tubulars from the rig mast and position them in selected positions in a horizontal storage rack. The pipe manipulation mechanism provides for variable and selective pipe travel paths between the rig mast and the storage rack, such that precise positioning relative to the rig is not critical, thus providing greater flexibility in field-positioning of the pipe handling unit to avoid interference with wellhead equipment, flow lines, shacks, and other wellsite appurtenances. The pipe handling unit does not require an elevated work platform, and thus eliminates safety risks associated with such platforms.
The pipe manipulation mechanism incorporates grapple means for grasping a section of pipe, with actuation means whereby the mechanism can transport a section of pipe from a vertical or inclined rig mast to the pipe storage rack (i.e., tripping out), or from the storage rack to the rig (i.e., tripping in). The mobile storage rack preferably will accommodate storage of pipe sections in a horizontal or near-horizontal position, with vertical “finger racks” to facilitate pipe placement in desired locations within the rack. Racking the pipes horizontally rather than vertically eliminates the need to guy the rig mast in many situations, thus leading to much faster rig-up and rig-down times. However, horizontal pipe storage is not essential to the invention; the apparatus could also be adapted for use with non-horizontal pipe storage racks.
The mobile storage rack preferably has adjustable downriggers or stabilizing legs which may be extended to bear on the ground surface and carry up to the full weight of the unit as necessary to level and stabilize the storage rack and thus facilitate accurate positioning of pipe within the rack. Downriggers may be of any suitable type, such as those commonly used in association with mobile cranes. Although the present invention does not require the use of downriggers of any particular type (or at all), preferred embodiments comprise a downrigger stabilizer system incorporating means for laterally shifting or slewing the pipe manipulation mechanism relative to the rig mast and wellhead after the unit has been parked, thus minimizing or eliminating the need for comparatively precise positioning of the pipe handling unit relative to the rig.
The pipe handling unit preferably includes a self-contained hydraulic power unit to actuate the pipe manipulation mechanism so as to manipulate pipe joints with optimal speed and efficiency to achieve pipe-handling cycle times that are at least as fast as those achieved using conventional methods and equipment. In alternative embodiments, however, power for actuating the pipe manipulation mechanism may be provided from a suitable auxiliary power unit, which may be but is not limited to a hydraulic power unit.
The pipe handling unit of the present invention is readily adaptable to automated control and operation, using known technologies such as but not limited to microprocessors and programmable logic controllers (PLCs), which are well known in the art. Automated operation is particularly advantageous for embodiments having vertical finger racks, as a computerized control system can readily determine and store in memory the positions of individual pipes within the storage rack and actuate the pipe manipulation mechanism to retrieve pipes from the storage rack in an automatic mode, thereby facilitating pipe handling without the pipes needing to be manually handled or manipulated.
Control of the pipe handling unit may be from a simple control panel that could be remotely mounted near the rig operator's control panel. The control system may include a set-up mode and an operational mode, with control of the unit being handled primarily by a PLC or other suitable programmable device to enable semi- or fully-automated tripping operations, depending on the desired level of operational integration with the rig.
Embodiments of the invention will now be described with reference to the accompanying figures; in which numerical references denote like parts, and in which:
In preferred embodiments as illustrated in the Figures, the pipe handling unit 100 of the present invention comprises a pipe manipulation mechanism (generally indicated by reference numeral 50) mounted to a mobile pipe storage rack which may be positioned as required adjacent to a drilling rig or service rig 1 having a mast 2. Rig 1 does not form part of the broadest embodiments of the present invention. In the illustrated embodiments, the mobile storage rack is provided in the form of a trailer 10, adapted to be transported and maneuvered as required by a suitable tractor unit (not shown). In alternative embodiments, mobile pipe storage rack may be a self-propelled unit with its own motor and drive train. Trailer 10 is preferably provided with front downrigger stabilizer legs 11 and rear downrigger stabilizer legs 12 which may be deployed to lift trailer 10 off of its tires 13, whereupon stabilizer extension slides (not shown) may be used to position trailer 10 as appropriate adjacent to service rig 1 and then trailer 10 is levelled.
Trailer 10 has a flat deck 10A which serves as a pipe storage area or storage rack 60. In preferred embodiments, one or more sets of vertical dividers or “finger racks” 14 extend upward from deck 10A, preferably with one set of finger racks 14F near the front end of trailer 10 and a second set of finger racks 14R near the rear end of trailer 10 as shown in
In preferred embodiments, pipe handling unit 100 incorporates an engine-driven hydraulic power unit (conceptually indicated by reference numeral 32) mounted to trailer 10, to provide pressurized hydraulic fluid for actuation of pipe manipulation mechanism 50. Preferred embodiments also incorporate a control system for pipe manipulation mechanism 50, also mounted on trailer 10 as conceptually indicated by reference numeral 33. However, alternative power means and control systems, including non-trailer-mounted and remotely-operated alternatives, may be used without departing from the concept and scope of the present invention.
As best appreciated with reference to
As indicated in the Figures, inner swivel arm 23 and outer swivel arm 25 may be of substantial width in the direction parallel to axes X-1 and X-2, and in preferred embodiments may be provided in the form of trussed frames as shown. However, this is only one of many possible configurations for inner swivel arm 23 and outer swivel arm 25, and the present invention is not limited to any particular form or structure for these components.
As perhaps best seen in
As shown in
Field operation of a pipe handling unit 100 in accordance with the present invention may be readily understood having regard to the Figures and the foregoing description. With trailer 10 positioned substantially parallel to a drilling rig or service rig 1 (as the case may be), with mast 2 of rig 1 being angularly oriented as required (i.e., vertical or inclined), main boom 17 is rotated upward until it is substantially parallel to tie axis of mast 2. Inner and outer swivel arm actuators 24 and 26 may then be operated as required to rotate slide member 28 to a position allowing grapples 30 to engage and grasp a pipe section 15 disposed within mast 2 (after removal from a drill string or production string), in conjunction with any appropriate adjustment of the axial position of slide member 28 relative to outer swivel arm 25. This process can then be reversed to rotate pipe section 15 out of mast 2 (as may be particularly well understood with reference to
It will be appreciated from
The foregoing describes the tripping-out procedure; for tripping-in operations, the process is simply reversed. During tripping-in operations, slide member 28 may be actuated to facilitate “stabbing” each added pipe section 15 into the upper end of pipe string 4 for thread makeup, thus minimizing or eliminating the need to use the rig's travelling block and elevator, and reducing the tripping-in cycle time as a result.
In preferred embodiments, the various actuators required to operate pipe manipulation mechanism 50 are hydraulically actuated and hydraulically controlled by use of suitable valves, which are in turn controlled by one or more PLCs or other programmable controllers or computers, based on control algorithms using control inputs from one or more sensors (not shown) of known types and applicability. Such sensors may include, but are not limited to, linear and rotational absolute position transducers, hydraulic fluid pressure transducers, proximity sensors, and other position-sensing technologies.
Preferred embodiments of pipe manipulation mechanism 50 may further comprise grapple extension means (not shown) for facilitating alignment of grapples 30 with a pipe section 15 disposed within the mast of a drilling rig or service rig. Such grapple extension means would be adapted to selectively extend one or both grapples (in concert, independently, or differentially) in a radial direction relative to slide member 28, so as to bring grapples 30 into optimal alignment with pipe section 15, even though the axis of slide member 28 might not be precisely parallel to the axis of the well (and pipe section 15). Accordingly, the apparatus can be adapted such that if grapples 30 are not optimally aligned with pipe section 15, the first grapple 30 to contact pipe sections 15 will not push it out of position, or if the pipe is constrained, it will not pull on outer swivel arm 25. Preferably, the control system of the apparatus will be programmed such that the first grapple contacting the pipe will sense, the contact and stop, allowing (and triggering) the other grapple to move into contact with pipe. Once both grapples 30 are in contact with the pipe, the gripping pressure applied by both grapples may be increased to an appropriate level before lifting the pipe. Persons of ordinary skill in the art will readily appreciate that the above-described functionality of the grapple extension means can be provided in a variety of ways using well-known technologies, such as (but not limited to) limit switches, linear potentiometer detection of position coupled with pressure or force transducer-generated inputs to PLC, or microprocessor-based automated control systems.
While preferred embodiments have been shown and described herein, modifications thereof can be made by one skilled in the art without departing from the scope and teaching of the present invention, including modifications which may use equivalent structures or materials hereafter conceived or developed.
The described and illustrated embodiments are exemplary only and are not limiting. For example, the illustrated embodiment of pipe manipulation mechanism 50 features two swivel arms (inner swivel arm 23 and outer swivel arm 25) with associated actuators 24 and 26. However, it will be readily appreciated by persons skilled in the art that alternative embodiments may include three or more swivel arms and corresponding actuators without departing from the concept and scope of the present invention.
It is to be especially understood that the substitution of a variant of a claimed element or feature, without any substantial resultant change in the working of the invention, will not constitute a departure from the scope of the invention. It is to also be fully appreciated that the different teachings of the embodiments described and discussed herein may be employed separately or in any suitable combination to produce desired results.
In this patent document, any form of the word “comprise” is to be understood in its non-limiting sense to mean that any item following such word is included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one such element. Any use of any form of the terms “connect”, “engage”, “couple”, “attach”, or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the subject elements, and may also include indirect interaction between the elements such as through secondary or intermediary structure. Relational terms such as “parallel”, “perpendicular”, “coincident”, “intersecting”, and “equidistant” are not intended to denote or require absolute mathematical or geometrical precision. Accordingly, such terms are to be understood as denoting or requiring substantial precision (e.g., “substantially parallel”) unless the context clearly requires otherwise.
This application claims the benefit, pursuant to 35 U.S.C. 119(e), of U.S. Provisional Application No. 61/051,280, filed on May 7, 2008, and said provisional application is incorporated herein by reference in its entirety.
Number | Date | Country | |
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61051280 | May 2008 | US |