Method for improving oil displacement efficiency of medium and low water-containing oil field

Abstract

The invention provides a method for improving the oil displacement efficiency of a medium and low water-containing oil field. Crude oil in the medium and low water-containing oil field is displaced and recovered by using a cocamidopropyl betaine solution. The method of the medium and low water-containing oil field includes the following steps that first, the cocamidopropyl betaine solution is prepared; second, preparatory work before the cocamidopropyl betaine solution is injected into an oil well is conducted; third, the cocamidopropyl betaine solution is injected into the oil well; fourth, clear water is injected in the forward direction, the cocamidopropyl betaine solution is driven and covered to an oil displacement area, and the well is shut in to wait for condensation; fifth, the clear water is alternately injected in the forward and reverse directions, after multiple cycles, the oil is washed back to drive into the oil well, and the water quality at an inlet and an outlet is consistent; sixth, oil well water absorption profile testing is conducted; and seventh, the step two to the step six are successively repeated until the crude oil in the oil well is recovered after multiple times of circulation. An oil recovery method can reduce the water injection pressure of the medium and low water-containing oil field, increase the output of the crude oil, and thus 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.