Homogeneous mixed intelligent oil displacement system, preparation method thereof and corresponding oil displacement method

Abstract

The invention relates to an oil displacement method for an oil reservoir, in particular to a homogeneous mixed intelligent oil displacement system, a preparation method thereof and a corresponding oil displacement method. Comprising a polymer and an auxiliary agent, the concentration of the polymer is 20-4000 mg / L, and the concentration of the auxiliary agent is 0.2-4 times that of the polymer. The oil displacement system has retardancy, diversity, growing property and permanency. By means of the method, damage to the low-permeability oil reservoir part can be avoided, the oil reservoir can be transformed in a wide range to achieve homogenization, perfect combination of homogenization transformation and efficient displacement can be achieved, and the recovery efficiency can be greatly improved. After being separated out, the polymer can enter smaller rock pores like water, so that the low-permeability driving efficiency is improved, and the problems of produced liquid treatment, safety and environmental protection caused after production are solved; the problems of difficult oil-water separation, substandard water treatment and difficult treatment of a large amount of sludge caused by extraction of a large amount of polymers in the conventional polymer flooding process are fundamentally solved.

Description

technical field [0001] The invention relates to an oil displacement method for a reservoir, in particular to a homogeneous mixing intelligent oil displacement system, a preparation method thereof and a corresponding oil displacement method. Background technique [0002] After primary and secondary oil recovery in oilfields, the water content of crude oil continues to increase, especially in old oilfields developed by long-term water flooding. With the large amount of crude oil produced, the heterogeneity of the oil reservoir is further aggravated, causing the injected water to flow along the injection wells and production wells. The intrusion and fingering of high-permeability layers or fractures in between will form an invalid circulation of injected water, resulting in premature water flooding of production wells, decreased oil production, increased water cut, and low recovery. Once this situation occurs, it is difficult to increase the swept volume of water flooding, and ...

AI Technical Summary

Problems solved by technology

[0007] The current successful polymer flooding technology has the problem of "high permeability cannot be plugged, medium permeability difference is large, and low permeability is unreachable". If the permeability is too large or the permeability range is too large, the ineffective cycle will occur quickly. Even if the permeability is extremely poor, due to the excellent and large difference in the plugging ability of the polymer to the medium permeability, the polymer flooding profile is reversed, and the ineffective circulation of the polymer will occur, because the molecular size of the polymer is much larger than Water and crude oil are difficult to inject into low-permeability parts, which will also affect the flooding efficiency of low-permeability

Once entering the follow-up water flooding stage after polymer injection, the development effect will immediately decline or even disappear. Therefore, large injection volume and high production concentration are common, which not only causes waste of polymer, but also seriously affects the treatment of produced fluid, and the production cost increases sharply.

Images