Claims:We Claim:
1. A pressure holding device used in hydrostatic testing of coal bed methane wellhead using high pressure, the pressure holding device comprising:
- a hydro plug (2) configured to hold pressure inside a coal bed methane well head (5), the hydro plug (2) provided with a ring groove on outer diameter to install O-ring (4) and a through hole for passage of test medium used during a hydrostatic testing;
- a cap nut (1) configured to provide support to the hydro plug (2) for restraining the emergence of the coal bed methane well head (5) while pressuring the coal bed methane well head (5) with a test medium;
- an internal threads machined in the cap nut (1), wherein the cap nut (1) are engaged with the external threads accessible in the coal bed methane well head (5) and provides predetermined reactional force during hydrostatic testing;
- O-Ring (4) provides a sealing between the coal bed methane well head (5) and the hydro plug (2); and
- a screw handle (3) provides grip while screwing the cap nut (1) into the coal bed methane well head (5).

2. The pressure holding device as claimed in claim 1, wherein the hydro plug (2) is configured to work as a connector between the pressure source/hydro pump and the coal bed methane well head (5).

3. The pressure holding device as claimed in claim 1-2, wherein the hydrostatic testing of the O-Ring (4) is configured to compress inside the ring groove which is provided in the hydro plug (2).

4. The pressure holding device as claimed in claim 1-3, wherein the O-Ring (4) is configured to provide required sealing and leak proof.

5. The pressure holding device as claimed in claim 1-3, wherein the O-Ring (4) provides sealing between the coal bed methane well head (5) and the hydro plug (2) while pressuring the coal bed methane well head (5) with the test medium.
, Description:PRESSURE HOLDING DEVICE USED IN HYDROSTATIC TESTING OF COAL BED METHANE WELLHEAD USING HIGH PRESSURE
FIELD OF INVENTION
[0001] The present disclosure, in general, relates to a pressure holding device used in hydrostatic testing of coal bed methane wellhead using high pressure. More particularly, the present invention relates to pressure testing of Coal Bed Methane (CBM) well heads for high pressure applications. Further, the pressure testing of CBM well heads with a novel hydro fixture. More particularly, the invention relates to method of pressure testing of CBM well head in an easy and safe way.
BACKGROUND OF INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Normally, coal bed methane well heads are used for extraction of methane from coal deposits by drilling wells into the coal seam. Coal bed methane is one of the factors required for the safe production of coal in underground coal mines. A wellhead is the component at the surface of a CBM well that provides the structural and pressure-containing interface for the drilling and production equipment. The primary purpose of a wellhead is to provide the suspension point and pressure seals for the casing strings that run from the surface pressure control equipment the bottom of the drill sections to the. Materials used for well heads are ASTM A216 WCC and A487 Gr.4 Cl-C.
[0004] Manufacturing of CBM Wellheads consists of following steps. Body machining, Non Destructive Testing-MPI, Full bore Valve (FBV) assembly, FBV hydro, CBM well head assembly, CBM well head hydrostatic test and final inspection. In the process of hydrostatic testing, the well head is filled with testing fluid and then specified pressure is applied for a specified length of time. The valve is then inspected for body strength by shell test and leakage by seat test.
[0005] In normal well heads, there will be two integral flanges at bottom and top of the well heads with ring joint grooves. Hydro test flanges are connected at both ends of well heads using ring joint gaskets and entire body will be pressurised with test fluid. Whereas CBM wellheads having threaded outlets at both ends and mounting the CBM wellhead on normal test flanges are difficult due to non-availability of ring joint grooves in the CBM wellhead. Moreover, wall thickness of CBM wellhead is also very less. Hence, there is a need to find out a new method for holding and performing the pressure testing for Coal Bed Methane Well heads. Further, this device should help in faster and safe holding while testing at high pressure.
[0006] Therefore, a need exists for a pressure holding device used in hydrostatic testing of coal bed methane wellhead using high pressure. Hence, the present invention has been introduced.

OBJECTS OF THE INVENTION
[0007] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed herein below.
[0008] It is a general or primary object of the present disclosure to provide a pressure holding device used in hydrostatic testing of coal bed methane wellhead using high pressure which obviates the disadvantages of the known art(s).
[0009] Further object of the invention is to provide to perform the hydrostatic test of the coal bead methane well head with a new holding device.
[0010] Furthermore object of the invention is to reduce the cycle time of manufacturing of CBM well heads in a safe way while holding of CBM wellhead at high pressure.
[0011] Yet another objective of the invention is to perform the hydrostatic test without strain while mounting the test fixtures.
[0012] These and other objects and advantages of the present disclosure will be apparent to those skilled in the art after a consideration of the following detailed description taken in conjunction with the accompanying drawings in which a preferred form of the present disclosure is illustrated.
SUMMARY OF THE INVENTION
[0013] This summary is provided to introduce concepts related to a pressure holding device used in hydrostatic testing of coal bed methane wellhead using high pressure. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0014] According to this invention, it has been principally decided to introduce a method for hydrostatic testing of Coal Bed Methane (CBM) wellhead using a pressure holding device. In the present disclosure, a method is used for hydrostatic testing that involves use of “pressure holding device” instead of hydro test flanges having ring grooves and manual tightening using bolts and ring groove gaskets. The above mentioned pressure holding device consists of cap nut, plug, O-Rings and handle bars. Pressure holding device is designed and developed according to the specification of valves.
[0015] In the existing pressure holding device for hydrostatic testing, integral flanges is provided at top and bottom of well heads with ring grooves which can be easily hold with hydro test flanges by using gaskets and bolts. Whereas, CBM well heads are having threaded outlets instead of integral flanges and also threads are of special type as per API Spec 5B. Further wall thickness at both outlets are very thin and it will be difficult with the existing method for conducting the hydrostatic test.
[0016] The present invention develops a new pressure holding device for hydrostatic testing that increases productivity and safety. It simplifies the existing method and operator strain will be reduced substantially.
[0017] The hydro plug is configured to hold the pressure inside the CBM wellhead and contains ring groove on an outer diameter to install O-ring and a through hole for passage of test medium used during hydrostatic testing. A cap nut is configured to provide support to a hydro plug for not coming out of the CBM wellhead during pressuring the CBM wellhead with test medium. An internal threads machined in the cap nut are engaged with external threads available in the CBM wellhead and provides required reactional force during hydrostatic testing. O-Ring provides proper sealing between the CBM wellhead and the hydro plug. During hydrostatic testing the O-Ring will compress inside the ring groove available in the hydro plug and provides required sealing and leak proof.
[0018] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figure in which like numerals represent like components.
[0019] It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.
[0020] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0021] The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and methods that are consistent with the subject matter as claimed herein, wherein:
[0022] Fig. 1 shows the full assembly view of pressure holding device having cap nut, hydro plug, screw handle and O-Ring, in accordance with an embodiment of the present disclosure; and
[0023] Fig. 2 & Fig. 3 shows the full assembly view of pressure holding device with Coal Bed Methane (CBM) well head unit, in accordance with an embodiment of the present disclosure.
[0024] The figures depict embodiments of the present subject matter for illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAIL DESCRIPTION OF INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS OF THE PREFERRED EMBODIMENTS
[0025] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to con all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0026] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0027] The present invention makes a disclosure regarding a pressure holding device used in hydrostatic testing of coal bed methane wellhead using high pressure.
[0028] Reference may be made to Figure 1, Figure 2, and Figure 3 which shows a pressure holding device machining and assembly, in accordance with an embodiment of the present disclosure. A solid cylindrical block is carried for making a cap nut (1). A boring operation followed by internal threading for cap nut (1) is carried out to screw into the outlet threads of Coal Bed Methane (CBM) wellhead (5). A female thread of cap nut (1) similar to male thread provided in the CBM wellhead (5), so that the cap nut (1) is screwed freely into the CBM wellhead (5). A through bore operation is carried for cap nut (1) at middle of the diameter to insert the hydro plug (2). Finally, to perform the operation for tapped hole on outer diameter (OD) of the cap nut (1) for fixing the screw handle (3) for hand grip to easy screwing into the CBM well head (5).
[0029] A solid cylindrical block is carried for making the hydro plug (2). O-ring groove is machined on an outer diameter (OD) of the hydro plug (2), so that while inserting the hydro plug (2) into the ID bore of CBM wellhead (5), O-ring (4) provides proper sealing during hydrostatic test and holds the pressure. A through bore and connecting thread machined along the axis of the hydro plug (2) for connecting the hydro hose from the pressure source.
[0030] In assembly, the O-ring (4) is assembled over the ring groove provided at outer diameter of the hydro plug (2) and same is inserted into the cap nut (1). Now, the pressure holding device is assembled with CBM wellhead (5) such that, the cap nut (1) is screwed into outlet thread available in CBM wellhead (5) and a hydro plug (2) goes into ID of the CBM wellhead (5). In similar way manufacture and assemble the pressure holding device on other outlet side of the CBM wellhead (5) according to type of thread available on the CBM wellhead (5). After assembly of the two holding devices at Inlet and outlet of the CBM wellhead (5), the sealing and pressure is held thereby successfully carrying out the hydrostatic testing of the CBM wellhead (5).
[0031] In the invention disclosed herein, the lengthy process of hydrostatic testing is reduced and eliminates numerous steps in the CBM wellhead setting. Hand tight screwing of pressure holding device into CBM wellhead is sufficient for proper sealing and holding pressure. Due to hand tight screwing, damages to threaded outlets having very thin wall thickness can be avoided easily.
[0032] Working of invention
[0033] The present invention is used for closing the inlet and outlet of CBM Well head while performing hydrostatic test to ensure valve body strength as per design requirement. While pressurising the CBM well head with test fluid, this invention which is assembled at inlet and outlets of CBM well head holds the test fluid inside the well head and allows pressure inside the wellhead to raise to the required hydrostatic pressure. This pressure holding device also provide leak-proof joints after assembled at inlet and outlet of CBM well head.
[0034] Test result of the present invention
[0035] Using the present pressure holding device, CBM wellhead is successfully hydro tested upto 4000 PSI with pressure holding period of 3 minutes. No visible leakages found in the Wellhead body and no pressure drop in the pressure gauge is observed. Hence the present device has successfully served its purpose.

TECHNICAL ADVANTAGES
[0036] There is a plurality of features which are listed as technical advantages below:
[0037] The present disclosure provides a pressure holding device used in hydrostatic testing of coal bed methane wellhead using high pressure which obviates the disadvantages of the known art(s).
[0038] The present disclosure performs hydrostatic testing of CBM Well head with a new pressure holding device.
[0039] The present disclosure reduces the cycle time for manufacturing of CBM well heads without strain and improved safety.
[0040] The present disclosure avoids the damages to the threaded outlets having very thin wall thickness.
[0041] The present disclosure provides a pressure holding device used in hydrostatic testing of coal bed methane wellhead using high pressure.
[0042] The present disclosure provide to perform the hydrostatic test of the coal bead methane well head with a new holding device.
[0043] The present disclosure configured to reduce the cycle time of manufacturing of CBM well heads in a safe way while holding of CBM wellhead at high pressure.
[0044] The present disclosure provides productivity by reducing the cycle time in the manufacturing.
[0045] The present disclosure is configured to perform the hydrostatic test without strain while mounting the test fixtures.
[0046] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[0047] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
[0048] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particulars claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances, where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B”.
[0049] The above description does not provide specific details of manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.
[0050] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[0051] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[0052] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.