涠洲11-1油田流沙港组储层损害机理

涠洲11-1油田主力储层流沙港组是低孔低渗透储层段,测井解释显示该段储层具有工业开采价值的地质储量。开发过程中使用油基钻井液,钻井完井液对储层造成损害导致生产井产能低或无产能。开展了单一钻井液和完井液、顺序工作液的动态损害评价、工作液与地层流体的配伍性评价等系列实验,探讨工作液的损害机理。研究表明,单一钻井液对储层损害程度弱,完井液对储层损害程度中等偏弱,而造成储层损害的关键因素是钻井完井液与完井液不配伍,产生大量白色絮状沉淀堵塞孔喉,导致储层产能低或者无产能。利用X-射线、能谱扫描、电镜研究表明,沉淀是由钻井液中10%CaCl2乳化液与射孔液中weight4加重剂生成的Ca3(PO4)2,矿场油井产出物佐证了室内研究结果的正确性。

Mechanism of Reservoir Damage Caused By Drilling and Completion Fluids In Liushagang Group of WeiZhou11-1 Oil Field

The main pay zone in Weizhou11-1 oil field is Liushagang group,which is of low porosity and low permeabilityreservoir,and the well logging shows it has commercial value of geological reserves.Oil base drilling fluid is used to openthe pay zone,but the oil wells have low or no production,which caused by reservoir damage.In order to reveal the damagemechanism,a dynamic compatibility evaluation of drilling fluid and completion fluid is developed,and the results show thatreservoir damages caused by single drilling fluid or completion fluid are low to intermediate,however,the main damagefactor is the incompatibility between drilling and completion fluids,which generates mass of white deposit that can notbe dissolved by acid and it may block up reservoirs.As the XRD,ESEM and EDS results demonstrate that,the deposit isCa3(PO4)2,which is produced by the 10% CaCL2 emulsion in drilling fluid and the weight 4 in completion fluid,also thedeposit is found in oil well output.