Wells – Processes – Assembling well part
Reexamination Certificate
2000-07-07
2001-04-24
Dang, Hoang (Department: 3672)
Wells
Processes
Assembling well part
C166S077100, C166S077510, C166S242100, C166S380000
Reexamination Certificate
active
06220361
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to circulating nipples used for filling well casing and for circulating fluid through well casing while setting or running the casing in a well, and more particularly, to a circulating nipple having an extended neck portion adapted for receiving a pipe wrench thereon and having holes therein adapted for receiving a handle or operating bar therethrough to facilitate installation and removal of the nipple.
2. Description of the Prior Art
It is conventional practice to drill a well to a desired depth and set casing in the well by running a casing string and then cementing the casing in place. The casing string is made up by connecting a plurality of casing sections or joints as the string is lowered into the well. The casing string is held stationary while each section of the casing is connected to the top of the existing casing string. The casing string is then lowered until the top of the string approaches the level of the rig floor. The next section of casing is assembled on the casing string, and the casing is again lowered. As each length of casing or casing section is connected, a circulating nipple, sometimes referred to as a circulating swage, is made up on the upper end of the casing string. The nipple is designed with a casing or tubing pin thread at the bottom and a smaller connection at the top for engagement with fluid flow lines. This top connection is typically a two-inch FIG. 1502 female connection.
Since the sections of the pipe forming the casing are relatively long, the top of the casing may be as high as thirty to forty feet above the rig floor which requires that the nipple be made up on the upper section of casing that far above the rig floor. This necessitates that the nipple be made up on the casing by hand and tightened with the use of hand-held chain tongs. Prior art circulating nipples are relatively long and heavy, and the outer surface of the nipple is usually a smooth, machined finish. This finish makes it difficult for the chain tongs to “bite” into the surface. As a result, the chain tongs frequently slip which can cause loss of balance of the person trying to make up the nipple as well as increasing the time required to complete the task. In addition, the weight and length of the nipple adds to the problem of maneuvering it into position on the casing.
Therefore, there is a need for a circulating nipple which is easier to handle and position on the casing string and which is also more easily made up on the casing string. The present invention addresses this need in several ways. Because-the nipple is designed so that it does not need to be made up with chain tongs, the length and weight of the nipple are approximately thirty to thirty-five percent less than prior art nipples. The lighter weight and shorter length combine to make the nipple easier to handle, especially when making up the casing string a large distance above the rig floor. A neck portion of the nipple has been lengthened compared to the prior art, allowing the use of a pipe wrench thereon if desired to make the nipple up in the casing. Further, holes have been provided on the circulating nipple which allow the use of a handle or operating bar to tighten the nipple. The operating bar is the same as, or similar to, the type used to open and close plug valves, such as Halliburton Lo-Torc® plug valves. Because the bar is inserted into a hole, there is extremely little chance that the bar will slip, thereby minimizing the dangers that are present with the use of chain tongs on prior art nipples. Thus, the circulating nipple of the present invention may be made up more quickly and in a manner which is relatively safer for the person making up the nipple and other personnel on the rig floor.
SUMMARY OF THE INVENTION
The present invention includes a circulating nipple-for use in running well casing into a well while pumping fluid into the casing string. The invention also includes methods of running casing into a well using the new circulating nipple.
The invention may be described as a casing nipple comprising a body portion having a casing thread thereon adapted for engagement with a casing connector and also comprising a neck portion extending from the body portion and having a union connection thereon. The body portion preferably defines a transversely extending hole therethrough adapted for engagement by a handle or operating bar. The neck portion preferably has a sufficient length such that a pipe wrench may be grippingly engaged with an outer surface of the neck portion. By using either or both the operating bar and/or pipe wrench, the circulating nipple may be easily threadingly engaged with the casing connector and made up on the casing string.
In one embodiment, the body portion further defines a slot thereon to facilitate drilling the hole. The slot has a radiused surface having a radius slightly larger than a radius of the hole. In one embodiment, the slot is one of a plurality of spaced slots on opposite ends of the hole. A central axis of the hole forms a chord with respect to an outside-diameter of the body portion.
A plurality of such holes may be spaced substantially evenly around the body portion. The hole central axes of each of the holes are substantially coplanar, and the plane in which the hole central axes lie is substantially perpendicular to a nipple central axis of the nipple.
Preferably, the body and neck portions are integrally formed. This may be accomplished by machining the nipple from a single piece of bar stock or by permanently attaching a plurality of elements to form the nipple, such as by welding.
Stated in another way, the invention includes an apparatus for use in a well comprising a length of well casing, a casing connector on the length of casing, a circulating nipple defining a central opening therethrough, and a fluid line. The circulating nipple comprises a body connected to an end of the connector and a neck extending from the body. The fluid line is connected to the neck. The fluid line may be further connectable to a fluid source such that fluid may be pumped when and as desired into the casing through the nipple as the casing is being run into the well. The neck may have a wrenching surface thereon of sufficient length for engagement by a pipe wrench, and the body portion may define a hole therethrough adapted for engagement by a handle or operating bar.
The present invention also includes a method of running casing into a well comprising the steps of providing a casing section or length of casing with a casing connector at an upper end thereof, positioning the casing adjacent to and aligned with an upper opening of the well, engaging a body of a casing nipple with an upper end of the casing connector, lowering the casing section into the well, disengaging the nipple from the casing connector, engaging an additional casing section with the casing connector, and engaging the body of the nipple with a casing connector at an upper end of the additional casing coupling. The method may also comprise the step of engaging a fluid line with the neck of the nipple. The step of lowering the casing may comprise pumping fluid through the fluid line and nipple into the casing section. The operator can pump liquid to fill the new section or sections of pipe and/or circulate fluid therethrough. The operator may do this after each section or after a plurality of sections is connected.
The step of providing the casing with a casing connector may comprise connecting a casing coupling to an upper end of the casing section or length of casing or may comprise simply providing an integral casing section with the casing connector forming an integral portion thereof, such as a female thread.
The step of engaging the body of the casing nipple may comprise using a pipe wrench on an elongated neck of the nipple and/or using a handle or operating bar extending through a hole defined in the nipple.
The steps may be repeated as desired to run additional casing sections or lengths of casing into t
Dang Hoang
Halliburton Energy Service,s Inc.
Roddy Craig W.
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