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

An adjustment method, a shale gas technology, is applied in the direction of earthwork drilling, wellbore/well components, production fluid, etc. It can solve problems such as unclear timing of choke adjustment, prolonged adjustment, and increased reservoir liquid phase permeability, etc., to achieve Avoid the rapid increase of liquid phase permeability and reduce the effect of operation time

Active Publication Date: 2020-07-10
BC P INC CHINA NAT PETROLEUM CORP +1
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AI Technical Summary

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.

Method used

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

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Effect test

Embodiment 1

[0032] As a preferred embodiment of the present invention, it discloses a method for adjusting the liquid discharge test nozzle after the fracturing of an atmospheric shale gas horizontal well, the steps of which are as follows:

[0033] (1) After the fracturing of normal pressure shale gas horizontal wells is completed, the wells are opened and drained, and the first stage is the stage of pure liquid phase flow. At this stage, only the liquid is discharged. Observe the salinity index of the flowback liquid. If the index remains relatively stable and the increase rate is less than 20% within 48 hours, it can be gradually increased in units of 1 mm after the liquid is discharged for 72-120 hours in a nozzle system; If the salinity increase exceeds 20% within 48 hours, immediately increase the 1mm nozzle; carry out the above procedures until the gas is seen;

[0034] (2) The initial stage of gas seepage refers to the stage when gas is discharged but the liquid discharge volume d...

Embodiment 2

[0037] Embodiment 2: Implementation example

[0038]Well A is a shale gas horizontal well at the southern edge of the Sichuan Basin. The target layer is the shale of the Longmaxi Formation. The vertical depth of the horizontal section is 2000-2050m, and the formation pressure coefficient is 1.2. It is a normal pressure shale gas well. The well has undergone fracturing in 20 stages.

[0039] Shut down the well for 230 hours after fracturing, and use a 3mm choke nozzle to open the well and drain the fluid for testing. The specific steps are as follows:

[0040] (1) The opening pressure is 12.5MPa, the pure liquid phase flow stage, the chloride content of the flowback liquid is 1791mg / L, and after 50h of liquid discharge, the chlorine content is 2349mg / L, no gas is seen, and it increases to a 4mm nozzle;

[0041] (2) The total liquid discharge time is 127 hours, the pure liquid phase flow stage, the chlorine root content is 5277mg / L, no gas is seen, and the nozzle is increased t...

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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 ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/12E21B43/00
CPCE21B43/12E21B43/121
Inventor 李军龙杨海朱炬辉石孝志陆丽吴晓容
Owner BC P INC CHINA NAT PETROLEUM CORP
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