义65井区高温低渗油藏储层伤害机理分析

FORMATION DAMAGE MECHANISM ANALYSIS OF HIGH TEMPERATURE AND LOW PERMEABILITY RESERVOIR IN WELL YI-65

义65井区沙三段九砂组油藏属中等水敏性和速敏性的地层,油藏为轻质油-稀油油藏,原油具有低密度、低黏度和高凝固点等特点,地层水总矿化度较高,一般为1100～19900mg/L,水型为NaHCO3型。研究了义65井区高温低渗储层伤害机理,从地层特性、注入水水质、悬浮物堵塞、游离油和乳化油滴、结垢、细菌及以往增产措施等方面评价了可能对储层造成的损坏及损坏程度。义65井区地层的水敏性、速敏性和低渗透性是注水井损害的内在因素,注水井中悬浮固相颗粒、含油量和细菌严重超标,水质不合格是注水井损害的外在因素。

The Jiusha Formation in Sha-3 member of well Yi-65 is a typical reservoir characterized by medium water sensitivity and speed sensitivity;the crude oil is light-thin oil possessing high solidification point,low density,viscosity and sulphur content;the salinity of the formation water can be as high as 1 100~19 900 mg/L in general,and the water belongs to sodium hydrogen carbonate typed water.This paper investigates the formation damage mechanisms of well Yi-65 with high temperature and low permeability,and evaluates the possible damage and damage conditions from the aspects of formation characteristics,injected water quality,suspended particle blocking,free oil,emulsified oil,scaling,bacteria and past stimulation treatments.The internal factors of the damage to water injection wells include water sensitivity,speed sensitivity and low permeability,and the external factors contain solid suspended particles,poor water quality,excessively high oil content and bacteria numbers.