Coal bed gas multilateral well recovery control stimulation device

Abstract

The invention discloses a coal bed gas multilateral well recovery control stimulation device, which comprises a main pipeline and at least two branch pipelines, wherein the front end of the main pipeline is connected with an air exhaust device used for simulating recovery control; the rear end of the main pipeline is communicated with the front ends of all the branch pipelines; the rear ends of all the branch pipelines are communicated with each other and are connected with a hydraulic pressure input device and / or a gas pressure input device; the main pipeline and the branch pipelines have the same structure and are coal reservoir simulation pipelines; and a flowmeter, a pulverized coal filtering device and a coal sample container are sequentially arranged on the coal reservoir simulation pipeline from the front to the rear. The coal bed gas multilateral well recovery control simulation device is developed under the conditions that the pressure transmission change is complex during multi-branch horizontal well recovery, the water yield and the gas yield are instable and the recovery is difficult to control, and different coal structures, different hydrogeology conditions, different permeability and different reservoir pressure conditions are simulated, so that the pressure transmission radius, the water yield, the gas yield and the pulverized coal changes during recovery are found out under different conditions.

Description

technical field [0001] The invention relates to a coalbed gas branch well drainage control simulation device. Background technique [0002] my country's coalbed methane resources are very rich. The latest round (2009) of national oil and gas resource evaluation results show that China's current geological resources of shallow coalbed methane buried below 2,000 meters are 36.81 trillion cubic meters, and the recoverable resources of shallow coalbed methane below 1,500 meters are 109,000. One hundred million cubic meters. The amount of coalbed methane resources far exceeds that of the United States, but the actual utilization of coalbed methane production is negligible. There are two main reasons for this: first, most of the coalbeds in my country are low-porosity, low-permeability, low-pressure, and low fluid seepage kinetic energy; It is because the series of experimental researches on different development technologies is not enough, resulting in no breakthrough in developme...

AI Technical Summary

Problems solved by technology

[0004] After the horizontal section of the current multi-branch horizontal well is drilled, generally no protective measures (such as lower screens, etc.) are taken. Because the coal seam fractures are relatively developed and the elastic modulus is relatively low, the wellbore in the horizontal section after drilling is very difficult. unstable, prone to collapse

When the drainage equipment is lowered for drainage, the liquid supply area of ​​the multi-branch horizontal well is relatively large, and the coal seam is a reservoir with strong heterogeneity, and because of the large number of branches, the change law of pressure transmission is relatively complicated, resulting in The outflow of reclaimed water is unpredictable, which increases the difficulty of drainage control

If the drainage work system is not properly controlled during drainage, it is easy to cause more and less outflow of water, resulting in the movement of coal powder in the coal reservoir, resulting in a decrease in permeability and affecting the gas production in the later stage; The inconsistency of the pressure transmission radius and the difference in the desorption radius in each branch lead to the difference in the gas production in the branches. If the drainage system is not proper, the gas production may fluctuate, causing the movement of coal powder and the permeability of coal reservoirs. Some injuries are even fatal, which may lead to no or very little gas production in the later stage

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