致密砂岩油藏增产过程中储层伤害机理

以鄂尔多斯盆地泾河油田致密砂岩油藏为研究对象,在常规分析方法基础上,分别对基质和裂缝性岩心进行了储层伤害实验,同时结合同位扫描电镜方法从微观角度对增产过程中的伤害机理进行了分析,找出了入井液侵入储层引起储层伤害的主要、次要原因,为该区块后续配方体系的改善提供了基础。研究结果表明,入井液侵入储层,黏土膨胀和水锁伤害是引起储层伤害的主要原因,结垢是次要原因;酸化过程中,酸液与酸敏性矿物反应产生二次沉淀及酸化后释放地层微粒是该储层酸敏性伤害的主要原因;压裂过程中,压裂液伤害的主要原因在于水锁伤害,而破胶不彻底产生的残渣伤害也是造成压裂液伤害的另一原因。

Research on Reservoir Damage Mechanism during Stimulation of Tight Sandstone Reservoir

Based on the conventional analysis method, the tight sandstone reservoir of the Jinghe oilfield in the Ordos Basin were studied, reservoir damage experiments were carried out on matrix and fractured core respectively, and the damage mechanism from the microscopic perspective in the stimulation process was analyzed in combination with in site scanning electron microscopy(SEM), the main and secondary causes of reservoir damage caused by the intrusion of fluids were found, which provided the basis for the improvement of the subsequent formulation system. The results show that the main causes of reservoir damage are clay expansion and water lock, scaling is the secondary cause when fluids intrusion; during acidification, secondary precipitation and release of formation particles is the main cause of acid sensitivity damage of the reservoir; during the fracturing process, the main reason for fracturing fluid damage is water lock, and residue damage caused by incomplete gel-breaking is another reason for fracturing fluid damage.