Method and device for measuring rock capillary pressure in reservoir temperature and pressure environment

Abstract

The invention discloses a method and a device for measuring rock capillary pressure in a reservoir temperature and pressure environment. The method comprises the following steps: 1) carrying out oil washing and salt washing on a rock core, and drying; 2) placing the rock core in a holder, applying confining pressure to the rock core by using fluorine oil, and heating the rock core; 3) carrying out a self-absorption experiment on the rock core, and monitoring the self-absorption behavior of the matrix part of the rock core by nuclear magnetic resonance; 4) after the self-absorption experiment is finished, enabling the rock core to be fully saturated with water, and acquiring the porosity of the rock core; 5) after the rock core is saturated with water, obtaining the permeability of the rock core by combining a constant flow method with a Darcy law; and 6) calculating to obtain a capillary pressure curve of the rock core in the reservoir temperature and pressure environment. The device is characterized in that the rock core is placed in a rubber sleeve, the rubber sleeve is fixed in a rock core holder, and the rock core holder is placed in a probe coil; and a nitrogen cylinder is sequentially connected with a displacement pump, a pressure sensor, a needle valve, a piston container and the needle valve. The capillary pressure curve of the core matrix part of the rock core under the reservoir temperature and pressure condition is obtained, and the method and the device are more suitable for being used on an oil reservoir development site.

Description

technical field [0001] The invention belongs to the technical field of nuclear magnetic resonance, and in particular relates to a method for measuring rock capillary pressure in a reservoir temperature and pressure environment, and also relates to a device for measuring rock capillary pressure in a reservoir temperature and pressure environment. Background technique [0002] In recent years, China's tight sandstone gas reserves have reached 1 / 3 of the total natural gas reserves, becoming the main source of domestic natural gas storage and production. Tight sandstone gas reservoirs in China are often characterized by low porosity, low permeability, and fractures. As an important physical parameter for evaluating tight sandstone gas reservoirs, the capillary pressure curve plays a vital role in the fields of reservoir exploration, reservoir evaluation, reservoir development, and seepage mechanism research. [0003] Currently commonly used core capillary pressure testing metho...

AI Technical Summary

Problems solved by technology

These three methods all perform capillary pressure tests on cores at room temperature, which cannot truly reflect the temperature conditions of tight sandstone cores in reservoirs

[0004] There are disturbances in the process of drilling and coring, and there are often micro-cracks or even cracks in the core. The capillary pressure curve of the rock part after the cracks are removed by the above three capillary pressure test methods cannot be obtained effectively.

The above three test methods are time-consuming and labor-intensive, requiring high equipment cost or time cost to obtain the capillary pressure curve of the core

It is difficult to reuse the core after the mercury porosimetry and centrifugation test, and it is difficult to obtain other parameters such as porosity and permeability from a core sample

Images