1. Field of the Invention
This invention relates to apparatus for placing tubulars in a well using a drilling rig. More particularly, apparatus is provided for remotely controlling alignment of joints of tubulars before joining.
2. Description of Related Art
The placement of tubulars in wells is normally carried out by hoisting a single joint of tubular (normally 30-45 ft. in length) into a vertical position over an assembly of tubulars (string) already placed in the well, aligning the hoisted joint of tubular with the string of tubulars, which is hanging in the well and supported by slips, rotating the hoisted tubular to thread the tubular into the string, raising the extended string to release the slips and lowering the extended string into the well. The process is repeated to make up a tubular string of the required length.
Tubulars having an outside diameter from about 2⅜ inches to about 36 inches are placed in wells. Tubulars placed in a well after the hole is drilled are called “casing,” and the diameter is normally more than 5 inches. Smaller tubulars, used as conduits for fluid flow in the well, are called “tubing.” Tubing is usually placed in a well using a “work over” rig, but it has the same type apparatus for running tubulars as a drilling rig, and is included in the designation “drilling rig” herein. A variety of automated equipment has been developed for placing both tubing and casing in wells. In most wells, where automated equipment is not available or is not economically justified, the placement of tubulars is still a “hands on” operation. The pipe tongs used to rotate tubulars during a placement operation are often hydraulically powered. Slips are usually handled manually, but may be hydraulic. The hoisting of each joint of tubular into a vertical position is performed with a small hoist in a mast over the well. The lowering of the entire string in the well is performed with the block-and-cable apparatus common to drilling rigs. The required lifting capacity of the mast is usually determined by the weight of the casing.
When a joint of tubular is in the vertical position, it must be aligned so that threading into the string of tubulars will not damage threads in the tubular. Generally, the joint being added has the male connection and the process of bringing the joints into position for threading is called “stabbing” the upper joint. When casing is being placed in a well each joint is much heavier than tubing joints, so aligning and stabbing casing are more difficult operations. The alignment operation is normally performed by a man standing on a platform in the mast (“derrick man”), which may be 30-50 ft. above the rig floor. Safety considerations arise when a man is required to stand above the level of the rig floor, because of the danger of falling. At the same time, it is necessary to thread the joints together without damaging threads in the tubular, which, with casing, can cause fluid to leak from the well and require expensive remediation steps to prevent an environmental risk.
U.S. Pat. App. No. 2012/0085550 discloses method and apparatus for stabbing tubular goods using an assembly attached to an elevator in a conventional drilling rig or a casing-running tool used in top drive drilling rigs. U.S. Pat. No. 7,770,654 discloses a pipe handling device for use with a top drive rig.
What is needed is apparatus for aligning tubulars for joining, without the need for a person positioned above the rig floor, that is economical to build and operate and that easily adapts for use with the variety of drilling rigs widely used in industry.
Apparatus is provided to be placed on the floor of a drilling rig, either conventional or top drive, which can be remotely operated to align tubulars, such as casing, for making threaded connections at the drill floor. Hydraulic or pneumatic cylinders or electrically-driven sources of force operate plates and fingers to control the location and orientation of a tubular as it hangs in an elevator and align the tubular with a connector on a mating second tubular, such that lowering and rotation of the first tubular with low torque makes a threaded connection.
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Alternatively, in another embodiment, fixed box member 14 may be attached to a fixed structure of a drilling rig, such as one or more vertical members of the mast of the rig. In this embodiment, base 11 and post 13 are not used, and operations of the apparatus may be performed with other elements as if base 11 and post 13 were supporting fixed box member 14.
In another embodiment, only one pair of pairs of fingers 22 or 23 may be present in finger assembly 20, but not both. It may not be necessary to have two pairs of fingers, as shown in
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All embodiments of a tubular aligning assembly disclosed herein may be used for placing any tubulars in a well with a rig; only casing will be discussed here. Assembly 10 may be placed on the floor of a drilling or completion rig. In another embodiment, post base assembly may be rigidly attached to one or more rigid members of the rig, such as a vertical member of the mast or the drill floor or substructure. Finger assembly 20 may then be operated to align the tubular being added to the tubulars in the well. A joint of casing, normally with male threads, is suspended in the mast by elevators. Slips support a string of casing that has been placed in a well, with a female connector above the slips. Normally, the position of elevators in a horizontal plane does not allow a joint to align with the connector such that the joint can be rotated at low torque, which is necessary to insure that threads on the joint and connector are properly mated. Preferably, some threads are engaged by manual force before tongs are applied to torque the connection to the recommended level. This minimizes the risk of cross-threading the connection, which is especially important in placing casing in a well. Operation of the cylinders or other apparatus to supply a driving force in the apparatus from a control panel allows alignment of a joint such that it can be joined to a connector by pipe threads at low torque even if the elevator is not vertically above the joint. The control panel may be on or off the drill floor. Observation of tubular alignment may be by visual observation and communication to an operator of the control panel, by a video camera and viewing screen for the panel operator or other sensors and communication channels for detecting the location of a joint with respect to a connector and communicating data to the panel operator.
Although the present invention has been described with respect to specific details, it is not intended that such details should be regarded as limitations on the scope of the invention, except to the extent that they are included in the accompanying claims.