In-situ spontaneous tackifying thickened oil displacement system and preparation method thereof

Abstract

The invention discloses an in-situ spontaneous tackifying thickened oil displacement system and a preparation method thereof.The oil displacement system is prepared from a surfactant system and thickened oil accounting for 4-6 vol% of the surfactant system according to the following steps that a surfactant, a cosolvent, basic salt and sodium chloride are dissolved in pure water at the normal temperature and stirred to be uniform, and the surfactant system is prepared; the method comprises the following steps: adding thickened oil into a surfactant system, uniformly stirring, sealing a container in which a solution is positioned, putting into a constant-temperature box, preserving heat for a period of time, taking out the container after heat preservation, uniformly mixing the solution in the container, and standing for a period of time to obtain the oil displacement system. The oil-deficient microemulsion obtained in the invention can realize ultralow interfacial tension (IFT) between a system and thick oil, and also has good rheological properties, so that the spontaneous thickening oil displacement system in the invention can be spontaneously thickened and has high viscosity; the problems that in the existing heavy oil reservoir oil displacement process, due to retention of injected polymer slugs, the physical property of a reservoir becomes poor, and the follow-up injection pressure rises are solved.

Description

technical field [0001] The invention relates to the technical field of oil and gas field development, in particular to an on-site spontaneously viscous heavy oil flooding system and a preparation method thereof. Background technique [0002] The world's heavy oil resources are very rich, and heavy oil resources are widely distributed around the world. According to the US Geological Survey estimates, there are more than 3.3 trillion barrels of heavy oil and 5.5 trillion barrels of asphalt resources in the world, of which Canada is the largest. Heavy oil resources are the most abundant. The exploitation of heavy oil began in the 1960s. After decades of development, the exploitation technology of heavy oil has undergone rapid progress. Up to now, the exploitation of heavy oil is mainly based on heavy oil thermal recovery technology (including combustion oil layer, steam stimulation, steam flooding, SAGD). However, there are still many limitations in thermal recovery of heavy ...

AI Technical Summary

Problems solved by technology

However, the multi-slug combination method of chemical flooding will inevitably increase the complexity of engineering construction. In addition, considering the poor fluidity of heavy oil in heavy oil reservoirs and poor reservoir physical properties in low-permeability reservoirs, the retention of polymers will increase. It leads to the increase of the residual resistance coefficient and damages the physical properties of the reservoir, which increases the displacement pressure difference

These problems caused by the use of polymers will not only lead to increased costs, increased engineering, and complicated processes, but also increase the risk of equipment damage

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