A gas permeability core clamping system suitable for multi-standard ultra-low permeability cores

Abstract

The invention provides a gas permeability core clamping system applicable for various specifications of ultra-low permeability cores. The gas permeability core clamping system comprises a confining pressure cavity and a permeation cavity, wherein one end of the confining pressure cavity is opened, and the permeation cavity is mounted inside the confining pressure cavity; the permeation cavity comprises a cylindrical leather sheath, a sealing plug, a chassis and an exhaust pipe, two ends of the cylindrical leather sheath are opened, the sealing plug is used for sealing the downstream end of the leather sheath respectively, the chassis is used for movably sealing the opened end of the confining pressure cavity, one end of the exhaust pipe is connected with an air outlet passage on the sealing plug in a welding manner, and the other end of the exhaust pipe passes through the chassis. Leakage points can be reduced as few as possible when large-diameter samples are measured, and meanwhile, when small-diameter samples are measured, a good sealing effect can also be guaranteed while the assembling is facilitated via O-type ring and thread sealing. Therefore, matched application of two-level or multi-level diameter is realized, extra plug and volume are avoided, dismounting and mounting of the connection of the plug and the exhaust pipe are reduced, the variable of testing and calculation is reduced, the time is reduced, the risk of gas leakage is reduced, the volume of a gas circuit remains unchanged all the time, and the experiment data processing is unlikely to make mistakes.

Description

technical field [0001] The invention relates to the field of petroleum engineering, in particular to a gas permeability core clamping system capable of measuring ultra-low permeability cores of different specifications. Background technique [0002] Rock permeability is an important parameter and index for reservoir physical property research, formation damage evaluation, and oil and gas reservoir development design. The permeability of shale gas reservoirs is very low, which is an important factor affecting the ultimate recovery. Use the method of liquid test or steady state test to measure the permeability below millidarcy (1md=9.87×10 -16 m 2 ) samples take too long and the signal is weak and the accuracy is difficult to guarantee. Therefore, the transient gas measurement method is generally used for measurement. [0003] The measuring equipment adopts the method of sealing both ends to measure the core to be tested inside. The measuring equipment adopts the design of...

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Problems solved by technology

[0003] The measuring equipment adopts the method of sealing both ends to measure the core to be tested inside. The measuring equipment adopts the design of small chambers at both ends, and the structure of detachable installation is adopted between the various parts. Once there is a small If there is a leak point, it may cause a significant change in pressure and affect the final measurement result

[0004] Existing measurement equipment has many connection points. When replacing rock cores of different sizes and lengths, it is necessary to disassemble the corresponding connection points of the measurement equipment and then install them. Frequent disassembly may lead to faster failure of sealing parts or a decrease in sealing performance. Such as the replacement of the plugs at both ends, the replacement of the exhaust pipe, etc., these actions are likely to cause subsequent damage or internal pressure leakage

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