Method for evaluating effects of pores with different dimensions on compressibility of total pore during pressurization

Abstract

A method for evaluating effects of pores with different dimensions on the compressibility of a total pore during pressurization comprises the following steps: configuring experimental simulated formation water; placing a core in a magnetic resonance imaging high-temperature high-pressure displacement system, and measuring magnetic resonance imaging T2 spectrums; drawing the magnetic resonance imaging T2 spectrums under different confining pressures on a same graph; according to magnetic resonance imaging T2 values, dividing the magnetic resonance imaging T2 spectrums into two parts, i.e., a part representing large pores, and a part representing small pores; respectively carrying out statistics on areas surrounded by the T2 spectrums of the large pores under the different confining pressures and the X axis, and areas surrounded by the T2 spectrums of the small pores under the different confining pressures and the X axis; and calculating compressibility coefficients of a total pore, the large pores and the small pores under the different confining pressures, calculating the sum of differences between the compressibility coefficients of the large pores and the compressibility coefficients of the total pore under the different confining pressures and the sum of differences between the compressibility coefficients of the small pores and the compressibility coefficients of the total pore under the different confining pressures, and determining effect degrees of the large pores and the small pores on the compressibility of the total pore. The method provided by the invention has the advantages that pore space changes are essentially reflected, the pore volume compressibility is used as a quantitative evaluation indicator, and the mechanism of pore changes under the pressures in a stress-sensitive process is disclosed.

Description

technical field

[0001] The invention relates to the technical field of oil and gas development, in particular to a method for quantitatively evaluating the influence of pores of different scales on the compressibility of total pores during the pressurization process. Background technique

[0002] During the development of oil and gas reservoirs, because the fluid in the pores is continuously produced, and the injection fluid is not replenished in time, the pressure of the pore fluid decreases and the original pressure balance is destroyed. Under the condition that the pressure of the overlying formation does not change, effective As the confining pressure increases, the pores deform under pressure, the pore volume decreases, and stress sensitivity occurs, which affects the efficient development of oil and gas reservoirs. The pore space of oil and gas reservoirs is composed of several pores of different sizes. The compressibility of large pores and small pores is different, a...

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