A 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 steps are as follows: 1) the rock core is washed with oil, salt, and dried; 2) the rock core is placed in a holder, and fluorine oil Apply confining pressure to the core and heat it; 3) Carry out self-priming experiments on the core, and monitor the self-priming behavior of the matrix part of the core with nuclear magnetic resonance; 4) After the self-priming experiment, the core is fully saturated with water to obtain the porosity of the core; 5) The core After saturated with water, the permeability of the core is obtained by the constant flow method combined with Darcy's law; 6) The capillary pressure curve of the core is calculated under the temperature and pressure environment of the reservoir. Also relates to the device, the rock core is placed in the rubber sleeve, the rubber sleeve is fixed in the core holder, and the rock core holder is placed in the probe coil; the nitrogen cylinder is connected with the displacement pump, the pressure sensor, the needle valve, the piston container, the needle valve in sequence valve connected. The invention obtains the capillary pressure curve of the rock core matrix part of the rock core under the temperature and pressure conditions of the reservoir, and is more suitable for field use in oil reservoir development.

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

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