Method and device for determining leakage rate of oil casing annulus of gas well

Abstract

The invention provides a method and a device for determining a leakage rate of an oil casing annulus of a gas well. The method comprises the steps of: acquiring basic data and annulus pressure relief data of the gas well, wherein the basic data of the gas well comprise an annulus wellhead pressure and an annulus protection liquid density; determining a gas temperature of a leakage point in an oil pipe and a gas pressure of the leakage point in the oil pipe based on the annulus wellhead pressure and the basic data of the gas well; determining a wellhead leakage rate based on the annulus pressure relief data and a surface pipeline hole leakage model; determining a gas well annulus leakage rate equation based on the wellhead leakage rate and the gas pressure of the leakage point in the oil pipe so as to determine the leakage rate of the oil casing annulus of the gas well. According to the method and the device for determining the leakage rate of the oil casing annulus of the gas well, the leakage rate of the oil casing annulus can be calculated by utilizing the daily production data of the gas well and the pressure relief parameters of the oil casing annulus, and the shortage that the leakage rate of the oil casing annulus of the gas well cannot be calculated currently is covered.

Description

technical field [0001] The invention relates to the field of gas recovery engineering, in particular to a method for calculating the leakage rate of annulus of a gas well casing. Background technique [0002] At present, with the continuous development of natural gas exploration and development, a large number of high-temperature, high-pressure, acidic medium gas wells have been put into trial production or put into production, and the ensuing gas well integrity problems have become increasingly prominent. The integrity requirement of a gas well is to ensure that uncontrolled overflow of subsurface fluids does not occur through management and technical means during the entire life. In the event of an integrity failure, the downhole natural gas will enter the oil casing annulus, that is, the annulus is under pressure, and the severe case may lead to abnormal pressure in the annulus, and even cause downhole natural gas to leak to the ground and explode, endangering the safety ...

AI Technical Summary

Problems solved by technology

In foreign countries, Scanwell Company of Norway has developed a set of special equipment, which can measure the depth and leakage rate of downhole leakage points at the wellhead, but the cost is high, and it only provides technical services, and it has not been applied in the scope of CNPC.

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