Experimental device and method of application of capillary tube with covering pressure

Abstract

The invention relates to a capillary experimental device with pressure, which is composed of a high and low temperature test chamber, an autoclave, a capillary column, a rubber sleeve, a fluid injection system and a fluid extraction system, and the upper surface of the capillary column is engraved with a spiral groove , the two ends of the groove are respectively connected to the fluid injection and extraction systems through vertical circular holes. The method for using the device to determine the miscible pressure of injected gas and crude oil includes: filling sand in the groove and round hole of the narrow pipe column; injecting hydraulic oil into the autoclave, and injecting nitrogen into the sand filled in the groove of the thin pipe column; The prepared formation crude oil is used to displace the nitrogen in the groove of the thin pipe column; the injected gas displaces the crude oil in the groove of the thin pipe column at a certain speed; the oil recovery rate R is taken as the ordinate, and the pressure P is taken as the abscissa, Draw the relationship curve between R and P, and the pressure point corresponding to the oil recovery rate of 90% is the miscible pressure of the injected gas and crude oil. The invention is reliable in principle and easy to operate, and can provide technical support for the scheme design of the actual gas injection and oil production process.

Description

technical field [0001] The invention belongs to the field of oil and gas development, and relates to an experimental device and a use method of a capillary tube covered with pressure. Background technique [0002] Crude oil mainly occurs in rock pores, and the recovery rate is not high by conventional depressurization mining methods. Especially for low-permeability and ultra-low-permeability reservoirs, the conventional recovery rate is not only low due to the small diameter of core pore throats, but also The chemical agent method cannot be implemented, and gas injection oil recovery is currently the main enhanced oil recovery technology. Gas injection flooding includes two types: miscible flooding and immiscible flooding. The main difference between the two methods is whether the injected gas front and oil are miscible during the displacement process. Theoretically, the efficiency of gas injection miscible flooding can reach 100%, which is much higher. in immiscible drive....

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Problems solved by technology

However, the existing thin tube method also has some defects. For example, the overburden pressure is not considered in the experimental process, and the lower limit of the permeability of sand filling in the narrow tube is limited. The sand can only be slowly filled into the thin tube without considering the cementation between sand particles, etc. The actual reservoir is quite different

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