Imbibition experimental device and imbibition experimental method under pulse action

Abstract

The invention relates to an imbibition experimental device and an imbibition experimental method under pulse action. The imbibition experimental method comprises the specific steps of preparing a to-be-tested rock core, mounting the rock core in an imbibitions device, and adjusting the length of an inlet screw, wherein the rock core is controlled between an inlet rock core groove and an outlet rock core groove; connecting the experimental device, adjusting a corresponding state by a three-way switch, filling a middle container with water, and adding a proper amount of water into a separating bottle through a drain pipe for oil-water separation; controlling a pulse controller to set a pulse signal of a certain frequency, starting a constant-flux pump to start pulse water injection and determining a pulse pressure value; and measuring the volume of oil displaced by imbibition action, and calculating the imbibition oil displacing recovery rate under the pulse action. By additionally arranging the pulse device based on a conventional imbibition experiment, influence on imbibition by pressure fluctuation and propagation is considered, great intervention of the displacing quantity on imbibition can be also removed, and the imbibition experimental device and the imbibition experimental method not only can be used for researching the imbibition oil displacing recovery rate under the pulse action, but also can be used for evaluating the oil displacing effects of natural imbibition and continuous water injection imbibition.

Description

technical field [0001] The invention relates to an imbibition experimental device and an experimental method under pulse action, and belongs to the technical field of physical pulse imbibition flooding enhanced oil recovery research. Background technique [0002] Imbibition is a process in which a porous medium spontaneously absorbs a certain wetting liquid due to capillary force. For hydrophilic reservoirs, water is the wetting phase and oil is the non-wetting phase. The water phase will enter the rock matrix along the pore throat due to the capillary force to displace the crude oil inside, increasing the oil recovery factor. . The main mechanism of waterflooding development in low-permeability fractured reservoirs is to absorb the water in the fractures into the rock matrix through imbibition and replace the crude oil inside. The development effect is of great significance. [0003] Pulse water injection causes an unstable pressure state in the formation by periodically...

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Problems solved by technology

[0004] At present, the indoor testing of imbibition oil production is mainly measured by natural imbibition, without considering the influence of pressure wave fluctuation and propagation on the effect of imbibition in the water injection process, resulting in the large influence of different water injection development methods on the measurement of imbibition in laboratory experiments error

Among them, the patent document "Pressure Pulse Improving the Efficiency of Injection Water Imbibition Displacement and Determining the Number of Pulses, Application No.: 201811320793.X" is the core flooding method used in this document (core flooding must set confining pressure before injection and Effective displacement at the production end), the oil displacement efficiency in the pulsating core displacement process includes the oil displacement in the pulsating water injection process, the pressure fluctuation in the intermittent pulse process, and the imbibition oil recovery due to pressure changes in the propagation process, and the document Instead of finely distinguishing displacement oil displacement and imbibition displacement, displacement and imbibition displacement are mixed together, which will cause calculation errors and inaccurate parameter optimization. In addition, the cost of accurate nuclear magnetic resonance is high, and the computer Processing data is complex, time-consuming and laborious, and it is impossible to effectively implement all core tests

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