一种低渗稠油油藏储层改造技术

A Technology for Stimulating Low Permeability Heavy Oil Reservoirs

针对低渗稠油储层物性差、原油黏度高,常规压裂改造效果差的难题,形成了以"储层改造+流体改质"为核心的储层改造技术。通过降黏剂评价实验,优选出阴离子型表面活性剂作为原油的降黏剂,优化降黏剂用量为3%。物模实验表明,降黏剂发挥最优降黏效果所需时间1~3d。优化形成超低浓度(0.18%)低伤害压裂液体系,60℃、170 s^(-1)剪切120 min压裂液黏度保持在100 mPa·s,形成以端部脱砂为主体的高导流压裂改造技术。该技术在华北油田X井进行现场应用,压后初期产油量为10.06 t/d,产水量为1.54 m^3/d,是邻井产量的3倍以上,压后3个月累积增油量达518 t,取得了好的改造效果,该技术的成功应用为同类型储层改造提供了很好的借鉴思路。

A set of technologies,with 4<reservoir stimulation plus fluid quality improvemenf,as the core technology,have been developed to stimulate low permeability heavy oil reservoirs,which have poor physical properties and high viscosity crude oil,and show poor stimulation results with conventional fracturing technology.An ionic surfactant was selected through laboratory experiment as the viscosity reducer for crude oil,and the dosage of the viscosity reducer was determined to be 3%through optimization.Physical simulation results showed that time required for the viscosity reducer to show optimum viscosity reducing effect was 1-3 d.A low damage fracturing fluid with ultra-low concentration(0.18%)viscosity reducer was formulated through optimization,and the viscosity of the fracturing fluid was maintained at 100 mPa.s after shearing the fluid at 60℃and 170 s-1 for 120 min.Using this fracturing fluid,a high conductivity tip screen-out fracturing technology has been developed.This technology has been applied on the well X in Huabei Oilfield,and the initial oil production rate after fracturing was 10.06 t/d,3 times o f the oil production rate of the adjacent well,and water production rate was 1.54 m3/d.The total amount o f oil increased 3 months after fracturing was 518t,indicating that the fracturing job was successful.This technology has provided a good clue for stimulating reservoirs o f the same type.