Patent Application
20190032422
The present invention relates to a tubular component used for drilling and operating hydrocarbon wells and landing heavy loads in a well or on or below the sea bed. The term “drill string or landing string component” means any element with a substantially tubular shape intended to be connected to another element of the same type or not in order, when complete, to constitute either a string for drilling or performing operations within a hydrocarbon well or a string for landing heavy loads in a well or on or below the sea bed. The invention is of particular application to other components used in a drill string or landing string such as drill pipes, heavy weight drill pipes, drill collars, and the parts of drill pipes, heavy weight drill pipes, and landing pipes which allow connection, and known as tool joints.
When a drill string is taken apart, removed, or connected, gripping slips are used to grip an area on the drill string or landing string component below the component being removed from, or connected to, the drill string or landing string.
Gripping slips have inserts with teeth to clamp the drill string or landing string component below the drill string or landing string component being removed or reconnected, and hold up the unsupported weight of the string below the slips. Due to repeated gripping of certain drill string or landing string components by the gripping slips, the area of the drill string or landing string component where gripping takes place may be more subject to fatigue failure from repetitive loading and unloading, and notching from each application of the slips' teeth. Accordingly, manufacturing a drill string or landing string component with a suitably long part life is challenging, since the components in a drill string or landing string must be capable in many cases of withstanding high tensile and compressive loads, bending and rotation under stress, as well as frequent slips clamping which results in hoop stresses, notching, and potential crushing of the drill string or landing string component.
U.S. Pat. No. 3,080,179 that issued Mar. 5, 1963 to C. F. Huntsinger claims a drill pipe construction with a thick-walled protector tube in the slip area of the drill pipe.
U.S. Pat. No. RE 37,167 re-issued May 8, 2001, to G. E. Wilson also claims an increased wall thickness steel protector tube for drill pipes, thus improving resistance to crack initiation and propagation.
Specifically Wilson proposed:
Wilson obtains a drill pipe with the protector tube that will run its full expected fatigue life without failing in notches and marks caused by slips in the rotary table.
Accordingly, increasing tube wall thickness where slips are applied on a landing pipe increases the landing pipe's resistance to stresses applied by the slips while the landing pipe is in tension. A trade-off between resistance to stresses and weight is needed to select tube wall thickness in the region where slips are to be applied.
Use of a material with a high Rockwell Hardness (HRC) makes the material stronger and the pipe more resistant to slip crushing, but more brittle and less resistant to crack initiation, and crack propagation, which may result from applying slips. In practice, yield strength ranges can be selected and the pipe treated accordingly to meet the desired material characteristics.
It is an object and feature of an exemplary embodiment described herein to provide a reduced weight landing pipe capable of maintaining high tensile loads. It is another object and feature of an exemplary embodiment described herein to provide a landing pipe less prone to fatigue and cracks. It is further an object and feature of an exemplary embodiment described herein to provide a landing pipe that improves landing operations.
One advantage of an exemplary embodiment described herein lies in reducing landing pipe weight, which reduces loading of drill string and landing string components and other handling equipment and drilling rig components. Reducing pipe weight can increase part life and extend the potential reach of the landing string. Another advantage of an exemplary embodiment described herein is an integral pipe design, where the pipe is designed with no welds. Identifying the location of a weld while running a landing pipe may increase the time required to run the pipe. In contrast, an integral design provides a larger vertical tolerance to apply the slips, such that it takes less time to set the landing pipe in the slips, leading to faster operations on a string.
In addition, an integral design yields a smoother bore with potentially less hydraulic turbulence, and less hang-up for tools.
These and other objects, advantages, and features of an exemplary embodiment described herein will be apparent to one skilled in the art from a consideration of this specification, including the attached drawings and the appended Claims.
A landing pipe comprises a first tool joint, a second tool joint, and a main section extending from the first tool joint to the second tool joint. In an exemplary embodiment the first tool joint can be an upper tool joint and the second tool joint can be a lower tool joint, or vice versa. The first tool joint outer diameter is greater than the largest main section outer diameter, and a first portion of the landing pipe main section has a greater tube wall thickness than a second portion of the landing pipe main section. In one embodiment, the tube wall thickness of the second portion of the landing pipe main section is reduced by boring the inner diameter. In another embodiment, the tube wall thickness of the second portion of the landing pipe main section is reduced by turning the outer diameter. In other embodiments, part of the first portion of the landing pipe main section can also have a reduced tube wall thickness directly adjacent to the first tool joint.
In an exemplary embodiment, the length of the second portion of the main section is between 40-85% of the overall landing pipe length, which provides sufficient length to set the slips. In a preferred embodiment, the length of the second portion of the main section is between 55-80% of the overall landing pipe length.
The characteristics and advantages of the invention are set out in more detail in the following description, made with reference to the accompanying drawings.
The present invention comprises a landing pipe designed to minimize weight. The present invention proposes an advantageous trade-off between wall thickness and overall weight, such that the landing pipe's resistance to crushing, tensile yielding, and fatigue is improved, yet the weight is manageable.
Referring to
In a preferred embodiment, the material used for the landing pipe is a high strength low alloy (HSLA) material such as 4100 or 4300 series alloy steel.
An exemplary embodiment of the present invention uses an integral design, defined as a design without welds. In an exemplary embodiment, no weld is present on the landing pipe between the main section first portion and the main section second portion. In a preferred embodiment no welds are present between the tool joints and main section such that the landing pipe design is entirely integral. Neither Wilson nor Huntsinger discloses a design which is integral in part or as a whole.
An exemplary embodiment of the present invention may have both an integral design and different mechanical characteristics along its length. The tube main section (2) requires a high yield strength to ensure a balance between pipe weight and resistance to tensile loads. A preferred embodiment of the present invention may use a main section with a higher yield strength, and tool joints (1, 3) with a lower yield strength. In an exemplary embodiment of the present invention, tool joints have a greater cross section than the main section, such that a higher force needs to be applied for the tool joint to yield, compared to the force required for the main section to yield. Tool joint threads are prone to damage due to their irregular shape, and use of a lower yield strength may prevent cracks from initiating in the threads.
In a preferred embodiment, the yield strength range (determined by physical testing with 0.2% offset) for the drill pipe's main section is between 135 ksi and 180 ksi. For commercial embodiments, a main section preferred yield strength range is between 150 ksi and 175 ksi. In a preferred embodiment the yield strength range of the tool joints is between 120 ksi and 160 ksi. For commercial embodiments, a tool joint preferred yield strength range is between 135 ksi and 150 ksi.
In an exemplary embodiment of the present invention, desired mechanical characteristics are obtained by first heat treating the entire tube (1,2,3) to obtain the required yield strength for the tube main section (2), and then applying a localized heat treatment on the tool joints (1,3). In an exemplary embodiment of the present invention, the localized heat treatment is applied using inductive coils, or any other method that ensures homogenous heat, both axially and throughout the thickness of the locally treated area. This localized heat treatment uses the same temperature as the heat treatment for the entire tube, with a different treatment time (tempering time) based on the material and thickness used. Tool joints treated with the localized heat treatment described above have lower yield strength and lower material hardness than the pipe's main section. A transition area exists between the low yield strength portions (tool joints) and high yield strength portion (main section), which may be located on the tool joints, preferably 1″ from the taper between the tool joint and the pipe main section.
Unlike Huntsinger and Wilson, the proposed invention does not use a protector tube. Indeed, the landing pipe's main section extends from one tool joint to the other tool joint. According to the present invention, the tube wall thickness is not increased. Instead, the present invention reduces the landing pipe weight by removing material from the main section's second portion.
Huntsinger disclosed using a protector tube with lower hardness than the main pipe portion (less notch sensitive), but with a protector cross-section large enough to obtain a total tensile and torsional strength no less than that of the main tube, despite the main tube having higher unit tensile and torsional strength than the protector tube. In other words, Huntsinger disclosed that the main section should have a higher hardness than the protector tube (notching being less of an issue outside of the protector tube). Wilson selected a protector tube with a hardness of 30-38 HRC. The present invention does not use a protector tube. Instead, the present invention can include a single main section between the tool joints. In a preferred embodiment, there is no section between the tool joints with a hardness lower than that of the main section, and there is no section characteristic of a protector tube.
Referring to
Referring to
Further, as illustrated
In the embodiment of
In both aforementioned exemplary embodiments the wall thickness of the main section second portion is reduced such that the landing pipe weight is reduced by at least 5% compared to a landing pipe with the wall thickness of the main section first portion equal to the main wall thickness of the main section second portion.
In an exemplary embodiment, the length of the second portion (2b) of the main section is between 40-85% of the overall landing pipe length, which provides sufficient length to set the slips. In a preferred embodiment, the length of the second portion of the main section is between 55-80% of the overall pipe length. In another preferred embodiment, the length of the second portion of the main section is between 55% and 65% of the overall pipe length.
Because many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.
The present application is a divisional of U.S. patent application Ser. No. 13/689,239 filed, Nov. 29, 2012, and entitled “Improved Landing Pipe,” the contents of which are herein incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13689239 | Nov 2012 | US |
| Child | 16140346 | US |
