Evaluation method for end part effects of seepage flow field

Abstract

The invention relates to an evaluation method for end part effects of a seepage flow field. According to the invention, special core nuclear magnetic resonance equipment is adopted to detect the distribution of a fluid flow field at the end part of a core to obtain an image of the forming process of the end part effect of the core. The method comprises the following steps: after the length, width, weight of the core are measured, the core is placed into salt water and is subjected to vacuumizing saturation by a vacuum vessel; the core is put into a rubber tube, is subjected to thermoplastic processing, then is put in a special clamp holder, and is put in a nuclear magnetic resonance test coil; two liquid storage tanks are respectively filled with two types of prepared displacement fluid; an MRI (Magnetic Resonance Imaging) and core application as well as displacement software is started up for recording core and displacement fluid data; the flow is adjusted well, the first type of displacement fluid is displaced in a certain pore volume until outlet liquid is anhydrous, then a pump is stopped, the flow is backward operated, and the second type of displacement fluid is adopted for displacement; a two-dimensional image of the core and fluid as well as a T2 spectrum is measured and recorded when PV numbers are different, and displacement is stopped when the PV numbers do not change; and the data is processed to obtain a signal cloud image of the fluid flow field at the end part of the core at different times.

Description

technical field [0001] The invention relates to an evaluation method for the end effect of a seepage flow field, and belongs to the fields of petroleum engineering enhanced oil recovery technology and experimental fluid mechanics. Background technique [0002] The core displacement experiment in the laboratory is a recognized method to study the fluid flow inside the core, and it is widely used in the fields of petroleum development and environmental science. At the same time, low-field nuclear magnetic resonance is a high-tech that has developed rapidly in recent years, and has been well applied in the medical and food industries. How to make the core displacement process in the laboratory closer to the actual field test situation has always been the goal and important work that has been pursued and carried out in the field of fluid mechanics and petroleum engineering technology. important factor in the process. The invention adopts the low-field nuclear magnetic reso...

AI Technical Summary

Problems solved by technology

[0005] Aiming at the end effect that actually exists in the existing core displacement process, although it is avoided as much as possible, it is difficult to specify the end effect. The purpose of the present invention is to provide an evaluation method for the end effect of the seepage flow field, which combines the core flow experiment and the nuclear magnetic resonance detection technology. Organically combined to form a new detection method, so that the end effect that cannot be detected by traditional instruments can be intuitively displayed, and the formation process of the end effect during the displacement process can be observed

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