临兴区块致密气储层压裂损害影响因素

On Factors Influencing Fracture Damage in Tight Gas Reservoirs,Linxing Block

为明确临兴区块致密气储层压裂损害影响因素,以储层岩心渗透率损害率为评价指标开展室内实验,分析储层敏感性、水锁效应、胍胶压裂液破胶残液和残渣含量对储层的损害程度。结果表明:储层具有中等偏弱水敏,弱—中等偏弱程度酸敏和碱敏;储层水锁指数为85%~100%,损害程度为强—极强;当使用单一过硫酸铵作为破胶剂,温度低于30℃时破胶黏度较大,对储层损害程度较强;压裂液残渣对储层渗透率损害率较低。临兴致密气压裂储层损害因素的损害程度由大到小依次为水锁损害、破胶残液损害、储层敏感性损害、压裂液残渣损害。该研究对临兴致密气压裂液体系和储层保护措施选择具有指导意义。

In order to identify the factors influencing the fracturing damage in tight gas reservoirs,Linxing block,laboratory experiments were performed with core permeability damage rate as an evaluation index to analyze the damage of reservoir sensitivity,water block effect,guar gum fracturing fluid residue after gel breaking and residue content to the reservoirs.The results showed that the reservoirs were moderately to weakly water-sensitive,and weakly to moderately weakly acid-sensitive and alkali-sensitive;the reservoir water block index was 85%to 100%,and the damage was strong to extremely strong;when single ammonium persulfate is used as gel breaker,the gel breaking viscosity was high at a temperature of lower than 30℃and the damage to reservoirs was strong;the damage rate of fracturing fluid residue to reservoir permeability was low.The extent of damage to Linxing fractured tight gas reservoir in descending order was water block damage,fracturing fluid residue damage after gel breaking,reservoir sensitivity damage,and fracturing fluid residue damage.This study plays a guiding role in the selection of fracturing fluid systems and reservoir protection measures for Linxing tight gas reservoirs.