Method for judging foam segment of coalbed methane shaft

Abstract

The invention discloses a method for judging a foam segment of a coalbed methane shaft and relates to the technical field of petroleum engineering. The method comprises the following steps that the simulative working fluid level height H in the coalbed methane shaft is measured; according to a downhole gas-liquid-solid three-phase flow pressure model and temperature, the real pressure PH and real temperature TH at the simulative working fluid level are obtained along a shaft depth distribution module; the pressure Pc of the critical working fluid level where the foam segment is produced is calculated; if PH is smaller than Pc, the foam segment exists in a well; and if PH is larger than Pc, no foam segment exists in the well. Through the method, whether the foam segment exists in the well can be judged accurately, and the length of the foam segment is judged accurately.

Description

technical field [0001] The invention relates to the technical field of petroleum engineering, in particular to a method for judging the foam section of a coalbed gas wellbore. Background technique [0002] With the continuous expansion of global energy demand and the depletion of conventional oil and gas resources, the large-scale development and utilization of unconventional resources is particularly urgent. As a typical unconventional resource, coalbed methane has huge global reserves, more than twice the proven reserves of conventional natural gas. The world's major coal-producing countries attach great importance to the development of coalbed methane. [0003] At present, the exploitation of coalbed methane usually adopts the method of oil pipe to produce water and casing to produce gas. In this method, the liquid in the oil jacket annulus is basically static, and the coalbed methane in the casing will continuously enter the oil jacket annulus, and then escape from the...

AI Technical Summary

Problems solved by technology

But if there is a foam segment, the height measured by the dynamic liquid level measuring instrument is the height of the top of the foam segment, not the real dynamic liquid level

When the foam section is long, it will lead to a large calculation error of the bottom hole pressure, and may induce the field personnel to think that the high dynamic fluid level will affect the drainage rate and greatly increase the water production, which will cause the reservoir pressure to release too quickly And cause reservoir damage, affecting the total production

Images