Device and method for testing core pore compressibility

Abstract

The invention relates to a device and a method for testing core pore compressibility. The method comprises the steps of selecting a core to be tested, wherein the core to be tested can be a low-porosity and low-permeability core; measuring the pore volume of the core by a saturated brine weighing method; calculating the volume coefficient of the brine used by an experiment; drawing volume shrinkage curves of a core holding unit and a connecting pipeline of the core holding unit; measuring the blank volumes of the core holding unit and the connecting pipeline of the core holding unit; measuring a core pore volume under each net effective pressure; calculating the measured results to obtain the core pore volume compressibility under all net effective pressures. By the device and the method, the core pore compressibility of the large-sized abnormal high-pressure low-permeability reservoir with can be tested and analyzed, and the error of the test results can be reduced.

Description

technical field [0001] The invention relates to an oil-gas field development rock core experiment analysis technology, in particular to a rock core pore compression coefficient testing device and a testing method thereof. Background technique [0002] The core pore volume compressibility coefficient is an important parameter in the physical research of oil and gas reservoirs, and it has important application value in evaluating the elastic productivity and dynamic geological reserves of oil and gas reservoirs. For abnormally high-pressure and low-permeability reservoirs, due to the small void volume of rock samples and the large span of formation pressure changes, it is difficult to measure the compressibility accurately. At present, the pore compressibility coefficient of abnormally high-pressure and low-permeability reservoir cores is the same as that of conventional cores, mainly following the national oil and gas industry standard with the standard number SY / T 5815-2008 ...

AI Technical Summary

Problems solved by technology

In the above method, helium is used as the medium for the initial pore volume, and brine is used as the medium during the overburden process. The pore volumes measured by the two different media must be different, and this difference is not considered during data processing and is classified as the pore compressibility coefficient. , which will obviously cause a large error

[0006] Second, compared to the pores of tight cores, the blank volume in the instrument (such as in the pipeline) is very large. In addition, the pressure span in the high-pressure reservoir simulation is large, and the volume of the brine itself as the measurement medium will also have a non-negligible volume during the experiment. change, and the above method does not consider the volume change of the brine itself, causing a large error

Due to the small scale of the cores used, it is difficult to establish the irreducible water saturation of the cores that matches the original water saturation of the actual reservoir for low-porosity and low-permeability cores, and the experimental process is difficult to be accurate due to the limited amount of saturated water in the pores. Measure the volume change of water

[0008] Fourth, the experimental pressure range of the above method is relatively low, and for the stress of abnormally high-pressure gas reservoirs, the variation range is obviously higher than 70MPa, and it is difficult for existing equipment to simulate the stress change of abnormally high-pressure reservoirs

[0009] Therefore, the existing core pore volume compressibility coefficient measurement device and its measurement method are difficult to meet the experimental test and analysis of the core pore compressibility coefficient of abnormally high-pressure and low-permeability reservoirs.

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