东营北带砂砾岩体裂缝伤害与保护

东营北带砂砾岩体属特低孔、低渗储层,裂缝的发育程度是决定储层物性的主要因素.研究表明:裂缝易于被常规聚磺钻井液所污染,尤其是钻井液中的无机固相及不溶有机物颗粒,且堵塞后不易排出.采用无黏土漂珠钻井液可实现欠平衡或近平衡钻井,且消除了固相污染,其主处理剂可在岩石表面堆积成膜,漂珠可对裂缝起到支撑作用,从而较好地保护了裂缝,污染后渗透率恢复值可达85.43％.

Glutinite Fracture Formation Damage and Damage Control Technology of North Zone of Dongying Depression

The glutinite blocks of the north zone of Dongying depression is kind of low-porosity, low permeability reservoir.The dominant factor of reservoir permeability is fractures, and drilling fluid is the first fluid contacting with formation fluid,so the low damage drilling fluid system should be used to reduce formation damage as far as possible.The laboratory research results show that, formation fractures are damaged easily by polysulphonate drilling fluid system, especially the inorganic solid particles and organic particles plug the formation fractures and make flowback difficult.The hollow glass bead drilling fluid can be used to obtain near balance or under balance drilling, because there is no solid damage to the reservoir for the drilling fluid system, and the major additives can absorb on rock surface, also the glass beads can support fractures of the formation,furthermore, the permeability recover value of the core acquired 85.43% with this drilling fluid system.