A method for improving oil displacement efficiency in medium and low water cut oilfields

Abstract

The invention provides a method for improving the oil displacement efficiency of medium and low water-cut oilfields. The crude oil in medium-low water-cut oilfields uses cocamidopropyl betaine solution to carry out oil displacement recovery, and the method for medium-low water-cut oilfields comprises the following steps: step 1. Cocamidopropyl betaine solution configuration; step 2, preparation before injection of cocamidopropyl betaine solution into the oil well; step 3, injecting cocamidopropyl betaine solution into the oil well; step 4, forward Inject clean water, drive and cover the cocamidopropyl betaine solution to the oil displacement area, shut down the well and wait for condensation; step 5, inject clean water alternately in forward and reverse directions, and after multiple cycles, backwash the oil flooding well to make the The outlet water quality is the same; Step 6, test the water absorption profile of the oil well; Step 7, repeat the above steps 2 to 6 in sequence, until the crude oil in the oil well is recovered after repeated cycles. The oil recovery method of the invention can reduce the water injection pressure of the medium-low water content oil field, increase the crude oil output, and further improve the oil displacement efficiency.

Description

technical field [0001] The invention relates to the technical field of crude oil recovery, in particular to a method for improving the oil displacement efficiency of medium and low water-cut oilfields. The oil recovery method of the invention is more suitable for the Chang 4+5, Chang 6 and Chang 8 oil reservoir areas of the Triassic of oil production. Background technique [0002] Crude oil is oil, also known as "black gold". It is customary to call unprocessed oil directly extracted from oil wells as crude oil. It is a dark brown or dark green viscous liquid or semi-solid combustible oil composed of various hydrocarbons. substance. [0003] my country's oilfield development stage implements water flooding to drive oil. After a long period of water injection, the current oilfield basically has three production stages: high water cut, ultra-high water cut, and medium-low water cut. In order to tap the remaining oil in these three stages, it is often used Technical method of ...

AI Technical Summary

Problems solved by technology

The method of crude oil recovery is mainly to improve the sweep efficiency and oil displacement efficiency, while the current conventional water injection well profile control aims to improve the sweep efficiency of injected water and increase the production of oil wells, but it is only suitable for high water cut and ultra high water cut stages In the water injection oilfields, the effect of increasing the crude oil production of medium and low water content oilfields is not good, and because the profile control increases the water injection pressure, the subsequent water injection is difficult, and the water injection fails to meet the requirements, resulting in insufficient injection, so that the remaining crude oil cannot be effectively displaced.