Rapid gravity replacement gas cut amount prediction method

Abstract

The invention discloses a rapid gravity replacement gas cut amount prediction method. The method comprises the steps that 1, the initial gas cut rate is determined according to stratum parameters and crack parameters; 2, the length of a leakage section at the moment t is determined according to the initial gas cut rate and the moment t; 3, the leakage amount and the gas cut amount at the moment t are determined according to the length of the leakage section at the moment t and the fracture pressure at the moment t; 4, according to the leakage amount and the gas cut amount at the moment t, the fracture pressure at the next moment is determined; and 5, the steps 2-4 are repeated according to the fracture pressure at the next moment until the time domain is finished, and obtaining the final leakage amount and the final gas cut amount. By utilizing a multiphase flow theory and a finite difference method and comprehensively considering the comprehensive influence of the fluid microelement stress condition and the fluid pressure distribution condition, the overflow amount and the leakage amount of the carbonate rock fractured formation after gravity replacement gas cut occurs are obtained.

Description

technical field [0001] The invention relates to a rapid prediction method for gravity displacement gas invasion, which belongs to the technical field of oil and gas field drilling. Background technique [0002] Fractured carbonate reservoirs have always been the focus and difficulty in the exploration and development of oil and gas reservoirs. For drilling engineering, the difficulty lies in the development of fractures and caves in carbonate formations, narrow safe density window, loss of Overflow occurs frequently, which poses a huge threat to well control safety. It takes a lot of time to deal with overflow and leakage problems, which affects the drilling cycle and further increases the drilling cost. Among them, gravity displacement gas kick is a very common form of gas kick, and its manifestation is that the fluid in the formation flows into the wellbore, and the drilling fluid circulating in the wellbore flows into the formation. After gravity displacement air intrusi...

AI Technical Summary

Problems solved by technology

However, for the case of gravity displacement gas invasion in fractured carbonate formations, when spillage coexists, the change in the mud pool is similar to the difference between the absolute values ​​of overflow and leakage, and the exact values ​​cannot be obtained.

Images