Method for adjusting oil nozzle through liquid drainage test after fracturing of normal-pressure shale gas horizontal well

Abstract

The invention discloses a method for adjusting an oil nozzle through liquid drainage test after fracturing of a normal-pressure shale gas horizontal well, and relates to the technical field of oil-gaswell liquid drainage test operation in the field of oil-gas field exploration and development. The method is characterized in that the whole liquid drainage test stage after fracturing of the normal-pressure shale gas horizontal well is divided into four stages of pure liquid phase flow, initial stage of gas breakthrough, gas increase and liquid drop and gas-liquid stabilization, four key indexesof wellhead pressure, flowback liquid mineralization degree, stage gas production rate and gas-liquid ratio are determined, and the adjustment time of the oil nozzle is determined by analyzing one ofthe key indexes of the four stages or the combination of the multiple key indexes of the four stages. According to the method, the key flowback parameters after fracturing of the normal-pressure shale gas horizontal well are judged, so that the adjustment time of the oil nozzle is judged, the complete oil nozzle adjustment method is established, the maximum yield of the normal-pressure shale gassingle-well test is achieved, and meanwhile, the overall test operation time is controlled.

Description

technical field [0001] The invention relates to the technical field of oil and gas well drainage testing operations in the field of oil and gas field exploration and development, in particular to a nozzle adjustment method in the drainage testing of normal pressure shale gas horizontal wells after fracturing. Background technique [0002] After fracturing, a shale gas horizontal well must pass a fluid drainage test for a certain period of time before it can be put into production. Can the fluid drainage test be used to achieve a high and stable test gas production as soon as possible, complete the evaluation of the fracturing effect and the calculation of the single well test production, and prepare for the production. It is the main purpose of this work to provide a basis for the formulation of the post-production system. At present, the shale blocks with commercial development capabilities in China are all developed in the Longyi No. 1 layer of the Lower Silurian Longmaxi ...

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Problems solved by technology

[0003] (1) There is no obvious rule in the gas seepage time after the normal-pressure shale gas well is opened and drained, but the low gas production period lasts for a long time, and the timing of choke adjustment is not clear. If the choke adjustment is too fast, the liquid phase permeability of the reservoir will increase rapidly, and the gas cannot be discharged ; If the adjustment is too slow, the entire drainage cycle will be extended and the operating cost will be increased

[0005] Therefore, the current fluid drainage test methods accumulated mainly through high-pressure and ultra-high pressure shale gas reservoirs cannot solve the problems encountered in fluid drainage testing after fracturing of normal-pressure shale gas horizontal wells.

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