Oil displacement and pressure reduction integrated method for increasing crude oil recovery ratio

Abstract

The invention discloses an oil displacement and pressure reduction integrated method for increasing crude oil recovery ratio. The integrated method comprises the following steps: S1, preparing an oildisplacement agent, and dividing the oil displacement agent into three parts, namely an oil displacement agent A, an oil displacement agent B and an oil displacement agent C, wherein the oil displacement agent is prepared from the components: cocamidopropyl betaine, a complexing scale inhibitor, a swelling reducing agent and a swelling shrinking agent; S2, diluting the oil displacement agent A, and then injecting the diluted oil displacement agent A into a perforation section layer of a water injection well; S3, diluting the oil displacement agent B, and then injecting the diluted oil displacement agent B into the perforation section layer of the water injection well; and S4, diluting the oil displacement agent C, and then injecting the diluted oil displacement agent C into the perforationsection layer of the water injection well. After the oil displacement agent is injected, the oil displacement agent can dissolve structural substances blocked in a stratum channel to form stable water-soluble compounds, channel blockage is avoided, betaine solution can quickly permeate into the structural substances to loosen the structural substances, the dispersed structural substances are dispersed into solution in a water injection channel, secondary precipitation of descaling substances is avoided, and the descaling effect is guaranteed.

Description

technical field [0001] The invention relates to the technical field of crude oil recovery, in particular to a method for enhancing crude oil recovery by integrating oil displacement and pressure reduction. The oil recovery method of the present invention is especially suitable for oil recovery in the Chang 4+5, Chang 6, and Chang 8 reservoir areas of the Triassic in Changqing Oilfield, wherein 4+5, 6, and 8 are the code names of oil layers in Changqing Oilfield. 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 med...

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 For oilfields with medium and low water cut, the profile control increases the water injection pressure, which leads to poor oil production in oil fields with low and medium water cut. During the process, long-term water injection produces minerals such as calcium carbonate, which leads to blockage of the water injection channel. During the continuous water injection process, water will accumulate somewhere in the formation, resulting in an increase in formation pressure and increased water injection resistance, which in turn will cause the water injection pressure to increase. Satisfying the purpose of water flooding, making subsequent water injection difficult, failure to meet the requirements of water injection leads to under-injection, so that the remaining crude oil cannot be effectively displaced