疏松砂岩储层油井岩石扩容增产技术及其应用

Rock dilation stimulation technique for production wells in unconsolidated sandstone reservoirs and its application

针对疏松砂岩储层产量递减快、增产技术难度大等难题,中国海上油田将一种用于稠油SAGD开发中的岩石扩容新技术应用于油井增产领域。利用宏观和微观2种方式对疏松砂岩储层油井扩容机理开展研究,首次在国内海上油田进行了2口井的现场试验,并从油井扩容增产工艺及关键参数方面进行应用研究。结果表明:疏松砂岩储层油井扩容主要包括剪切及张性裂缝带的形成和近井反向解堵2种机理;岩石扩容的地应力测试、地应力预处理、扩容区扩展和扩容区反演4个工艺步骤中,需重点关注扩容压力、扩容半径、扩容频率和扩容反演配套参数;2口实验井作业后,P‑B7H1井的产液量由213.7 m^(3)/d增加至405.2 m^(3)/d,地层孔隙度增加了1.6%~2.0%,E‑A9H井的产液量由236.7 m^(3)/d增加至510.0 m^(3)/d,平均渗透率由386.2×10^(-3)μm^(2)增加至808.0×10^(-3)μm^(2)。岩石扩容技术可用于疏松砂岩储层油井增产,具有广阔的应用前景,为油田增产提供了一种新思路。

Aiming at challenges of fast production decrease of unconsolidated sandstone reservoirs and difficulties in stabilizing production by stimulation techniques,a new rock dilation technique for heavy oil SAGD development is applied in production wells stimulation areas of China’s offshore oilfields.The mechanism of rock dilation in production wells in unconsolidated sandstone reservoirs is understood by both macroscopic and microscopic methods,and field tests of 2 wells are carried out for the first time in China,with study in perspective of production wells’rock dilation and stimulation technique and key parameters.The results show that well rock dilation in unconsolidated sandstone reservoir mainly has 2 mechanisms including the formation of shear and tensile fracture zones and near-wellbore reverse plug removal.Among 4 technical steps of rock dilation including in-situ stress testing,in-situ stress preprocessing,dilation zones expansion and dilation zones inversion,attention should be paid on dilation pressure,dilation radius,dilation frequency,and supporting parameters for dilation inversion.After the operation of 2 experimental wells,Well P-B7H1 has fluid production increased from 213.7 m^(3)/d to 405.2 m^(3)/d and formation porosity increased from 1.6%to 2.0%,and Well E-A9H has fluid production increased from 236.7 m^(3)/d to 510.0 m^(3)/d and average permeability increased from 386.2×10^(-3)μm^(2)to 808.0×10^(-3)μm^(2).This technique can be used for production wells stimulation in unconsolidated sandstone reservoirs and has broad application prospect,providing new idea for stimulation techniques in oilfields.