The present disclosure relates generally to downhole tools, and specifically to fittings for downhole logging tools.
While drilling for underground hydrocarbon formations, many material properties may be logged to allow a driller to better understand the underground formation. Material properties may be determined utilizing electromagnetic waves emitted and received by a measurement device in a downhole tool. One such material property is resistivity. Resistivity measurement tools generally allow the driller to determine the resistivity or resistance to the conduction of electricity of the surrounding formation. By knowing the resistivity of the surrounding formation, an operator can make determinations about the makeup of the formation including, for example and without limitation, the presence or absence of water or hydrocarbons, as well as the porosity and/or permeability of the formation.
For some downhole tools which utilize electromagnetic waves, the measurement device is positioned within a tubular segment or collar referred to herein as a tool collar. The collar may be positioned as part of a tubular string including a plurality of tubular segments. By including the measurement device as part of the drilling string, measurements may be made during the drilling operation. In some tools, the measurement device is formed as a probe or sonde located within the collar. In other downhole tools, the measurement device may be coupled to but located within the collar. Unlike external antenna tools, in which the conductors are positioned on the exterior of the collar, a probe based tool or internally located tool may include antenna elements located internal to the collar.
Internal antenna tools may operate by transmitting an electromagnetic field through the formation between one or more transmitter antennae to one or more receiver antennae spaced apart along the tool string. One or more slots may be formed through the wall of the collar corresponding generally with the placement of each antenna of the probe. Because the collar is made of a conductive material, the electromagnetic field would be attenuated if not blocked altogether from entering the surrounding formation without the slots. Because of the necessity to maintain differential pressure between the interior and exterior of the tool string, the slots must be sealed with a resilient yet electromagnetically transparent plug. Probe based resistivity tools are discussed in more detail in U.S. Pat. No. 6,483,310, filed Oct. 17, 2000 (“Retrievable, formation resistivity tool, having a slotted collar”), the entirety of which is hereby incorporated by reference.
The present disclosure provides for a plug assembly for plugging a slot having an inner edge and an outer edge formed in the wall of a tubular member. The plug assembly may include a plug including a plug body having an inner face and an outer face; an inner retainer, the inner retainer having a shape corresponding to the shape of the inner edge of the slot and an inner retainer slot corresponding to the shape of the inner face of the plug; and an outer retainer, the outer retainer having a shape corresponding to the shape of the outer edge of the slot and an outer retainer slot corresponding to the shape of the outer face of the plug, the outer retainer coupled to the inner retainer with the plug disposed therebetween.
The present disclosure also provides for a method of installing a plug assembly. The method may include forming a slot in the wall of a tubular member, the slot including an inner edge and an outer edge; installing an inner retainer within the inner edge of the slot, the inner retainer having a shape corresponding to the shape of the inner edge of the slot and an inner retainer slot corresponding to the shape of an inner face of a plug; installing the plug within the inner retainer slot, the plug including a plug body having the inner face and an outer face; installing an outer retainer within the outer edge of the slot, the outer retainer having a shape corresponding to the shape of the outer edge of the slot and an outer retainer slot corresponding to the shape of the outer face of the plug; and coupling the outer retainer to the inner retainer.
The present disclosure also provides for a system for the measurement of a parameter of a formation surrounding a wellbore. The system may include a collar, the collar being a generally tubular member, the collar including one or more slots, the slots including an inner edge and an outer edge. The system may also include a measurement device positioned within the collar, the measurement device including at least one energy transmitting or receiving antenna, each antenna positioned to generally correspond with at least one of the slots. The system may also include a plug assembly for plugging each slot. The plug assembly may include a plug including a plug body having an inner face and an outer face; an inner retainer, the inner retainer having a shape corresponding to the shape of the inner edge of the slot and an inner retainer slot corresponding to the shape of the inner face of the plug; and an outer retainer, the outer retainer having a shape corresponding to the shape of the outer edge of the slot and an outer retainer slot corresponding to the shape of the outer face of the plug, the outer retainer coupled to the inner retainer with the plug disposed therebetween.
The present disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
With regard to
In some embodiments, the profile of the wall of slot 105 may be formed about the entire perimeter of the slot with outer groove 119 and inner groove 121 to form clamping extension 122. In some embodiments, outer and inner grooves 119, 121 may be generally rectangular to form a generally rectangular clamping extension 122. As depicted in
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In some embodiments, as depicted in
In some embodiments, as depicted in
The components of collar plug assembly 109—collar plug 111, outer retainer 113, and inner retainer 115—may be formed from a material that is generally electromagnetically transparent to the electromagnetic field generated or received by antennae 107 of measurement probe 103. In some embodiments, the components of collar plug assembly 109 may be formed from an insulator material including for example and without limitation a polymer or rubber material. Additionally, the components of collar plug assembly 109 may be formed of a material having sufficient strength to withstand the differential pressures encountered during normal drilling operations. Furthermore, the components of collar plug assembly 109 may be formed of a material that is non-reactive with any fluids naturally or artificially present within wellbore 10 which may be encountered during a drilling operation.
In order to assemble tool assembly 100, slots 105 are formed in a tubular segment to form tool collar 101. Slots 105, as previously discussed, may be positioned to generally correspond with the location of the one or more antennae 107 of measurement probe 103. One having ordinary skill in the art with the benefit of this disclosure will understand that in some embodiments, multiple slots 105 may be formed in tool collar 101 around each antenna 107. The number and geometry of slots 105 (including but not limited to slot length and width) may be varied to, for example, provide sufficient electromagnetic transparency for each antenna 107 while retaining sufficient structural strength for tool collar 101. Such determination may take into account, for example and without limitation, the diameter and wall thickness of tool collar 101. In some embodiments, three slots 105 may be formed to surround each antenna 107. Furthermore, although
Slots 105 may be formed in tool collar 101 by any known suitable method of manufacture. Slots 105 may be formed in multiple steps using multiple methods of manufacture. In some embodiments, slots 105 may be formed by milling.
Once slot 105 is formed, inner retainer 115 may be inserted into inner groove 121 of slot 105. In some embodiments, inner retainer 115 may be inserted through slot 105. In other embodiments, inner retainer 115 may be inserted through the end of tool collar 101. In some embodiments, inner retainer 115 may be held into slot 105 using a tool inserted into the end of tool collar 101.
Collar plug 111 may then be installed into inner retainer 115. In some embodiments, as previously discussed, internal extension 141 may be inserted into inner retainer slot 135.
Outer retainer 113 may then be installed into slot 105. In some embodiments, as previously discussed, external extension 143 may be inserted into outer retainer slot 127 as outer retainer 113 is installed. Threaded fasteners 117 may then be inserted into outer fastener holes 140 and screwed into inner fastener holes 142.
In some embodiments, as collar plug assembly 109 is assembled in slot 105, one or more seals 145 may be installed as previously discussed, to, for example, enhance the fluid seal between the components of collar plug assembly 109. In some embodiments, an adhesive may be introduced between the components of collar plug assembly 109.
Once a collar plug assembly 109 is assembled in each slot 105 of tool collar 101, measurement probe 103 may be inserted into tool collar 101. In some embodiments, measurement probe 103 may be installed during the makeup operation of tool collar 101 into a drill string at the wellsite. In other embodiments, measurement probe 103 may be installed beforehand. In some embodiments, tool collar 101 may include threaded couplers as understood in the art adapted to allow tool collar 101 to be coupled to adjacent tubular segments in the drill string.
The foregoing outlines features of several embodiments so that a person of ordinary skill in the art may better understand the aspects of the present disclosure. Such features may be replaced by any one of numerous equivalent alternatives, only some of which are disclosed herein. One of ordinary skill in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. One of ordinary skill in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.
This application is a nonprovisional application which claims priority from U.S. provisional application No. 61/987,203, filed May 1, 2014, the entirety of which is hereby incorporated by reference.
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61987203 | May 2014 | US |