基于微流控模型的渤海典型高渗砂岩储层油水赋存规律

Oil-Water Occurrence Law in Typical High-Permeability Sandstone Reservoirs in the Bohai Sea Based on Microfluidic Modeling

为进一步明确高渗砂岩储层水驱过程中微观油水赋存规律,通过扫描储层岩心,建立了渤海高渗砂岩微流控模型;基于形状因子和欧拉数等微观参数,编制计算程序,精细识别并提取膜状、滴状和柱状等5类剩余油的微观表征;针对不同流体物性及开发方式设计实验方案,明确了渤海典型高渗砂岩在不同原油性质及开发制度下微观油水赋存规律及演化特征。结果显示:随着剩余油非连续相增加,水淹范围内的绕流区、滞留区难以再动用,多孔和簇状剩余油成为主要的剩余油赋存形态;高速驱替水驱波及范围更大,但注入水绕流易导致采出端提前见水,波及范围不再显著增加;低黏储层中,高速驱替相较低速驱替波及系数提升0.154;高黏储层中,液流改向调整后水驱末期波及系数提高0.137。对于渤海油田典型储层物性及高含水开发阶段条件下,低黏储层更适合提高驱替速度进行挖潜,高黏储层适合液流改向进一步动用剩余油。研究结果为渤海油田水驱高效开发提供了借鉴。

In order to further clarify the microscopic oil-water occurrence law during the water flooding process in high-permeability sandstone reservoirs,a microfluidic model of high-permeability sandstone in the Bohai Sea was established by scanning the core of the reservoir;based on the microscopic parameters such as the shape factor and Euler number,the computational program code was prepared to finely identify and extract the microscopic characterization of the remaining oil of five types,such as film,drop and column;and the experimental scheme was designed for the different fluid properties and development modes,so as to clarify the microscopic oil-water occurrence law and the evolution characteristic of the typical high-permeability sandstone of the Bohai Sea in the context of the different crude oil properties and the development regimes.The results show that With the increase of remaining oil discontinuous phase,it is difficult to produce the flow-around zone and stagnant zone within the water flooding range,and the porous and clustered remaining oil has become the main remaining oil occurrence pattern;high-speed displacement of water flooding has a larger sweep range,but the injected water flow-around is easy to lead to the water visible at the extraction end in advance,and the reach is no longer significantly increased;in low-viscosity reservoirs,the sweep efficiency of high-velocity displacement is increased by 0.154 compared to that of low-velocity displacement;in high-viscosity reservoirs,the sweep efficiency at the end of water flooding is increased by 0.137 after the liquid flow redirection and adjustment.For the typical reservoir properties of Bohai Oilfield and the conditions of high water content development stage,low-viscosity reservoirs are more suitable for increasing the displacement rate for potential tapping,and high-viscosity reservoirs are suitable for liquid flow redirection to further produce the remaining oil.The research results provide a reference for the efficient development through water flooding in Bohai Oilfield.