Research On Surfactant Flood Effect Assessment Of Low And Extra-Low Permeability Reservoir

With the rapid development of China’s economy, the demand for oil is increasing. However, due to the limited amount of oil and gas resources as well as oil and gas production, the country’s dependence on foreign oil imports is increasing. On the status of China’s current oil development point of view, most of our good oil regions are in high water stage. So low and extra-low permeability reservoir development become the most important direction in increasing oil production of China. The special conditions of formation and occurrence of low permeability reservoir made the low oil recovery. Therefore, on the issue of improving oil recovery in low permeability reservoirs become the focus of the current academic oil research, as well as residual oil distribution and of displacing agent of different types, especially research on multiphase fluid flow in low permeability reservoir characteristics, thus. However, there is no research have made a systematic study and analysis of these agents that improving recovery on low permeability reservoir of the Yanchang Formation.This paper take Yanchang hypotonic extra-low permeability reservoirs as subject investigated, combined with the relatively advanced model of the real sandstone micro-displacement experimental technique for water flood residual oil phase of the oil to be active agents flooding experiments. To Study its flooding process flow characteristics, changes in water distribution and calculate its oil displacement efficiency. And enhanced oil recovery mechanism was doing some discussion, thereby evaluating the effect of surfactant flooding.1, the study area for the main types of microscopic displacement model there are two types of non-uniform displacement of the finger-like flooding based;2, microscopic model study area water flood residual oil residual oil end of the causes can be divided according to their type of flow around the formation of a film of residual oil, the card off blind hole-like droplets and residual oil formation;3, after injection surfactant, the fluid flow characteristics of the model is same to the end of water flooding, the number and size of residual oil are significantly reduced;4, according to the experiment studies suggest that the mechanism of low permeability and low permeability reservoir characteristics of the main surfactant flooding mechanism to reduce the interfacial tension, emulsification mechanism, improve the mechanism of rock surface charge density, wettability reversal mechanism, changing the flow of the crude oil and other than the mechanism, in which the study area special low permeability reservoir of surfactant flooding efficiency play a decisive role is to reduce the interfacial tension mechanism;5, the injection of active agent, oil displacement efficiency is significantly improved, incremental oil displacement efficiency up to10%;6, the study of microscopic displacement zone model for the experimental study of the reservoir considered the primary factors affecting physical property conditions the efficiency of surfactant flooding, the injection volume of reservoir heterogeneity and active agents have a grater impact on oil displacement efficiency, driving pressure effect on oil displacement efficiency has some limitations.Through the experimental observations and data analysis, made the following findings: In this paper, the active agent is on low permeability reservoir injection flooding conditions, injection volume, and studied the effect of flooding in Yanchang Formation permeability, the actual production of ultra-low permeability reservoir development to provide some reference, which is of great significance to improve the protection and development of oilfield production.