影响低渗高压层固井质量的因素及其预测方法

Factors Affecting Well Cementing Quality in High Pressure Layer of Low Permeability and Its Prediction Method

通过对室内试验和现场实际资料分析，阐述了低渗高压层的物理特征及其固井质量影响的因素。当环空压差小于－４０ＭＰａ、声幅在９０％以上时，液体在空套管内会形成窜槽现象。将环空压差为１０ＭＰａ定为最佳环空压力值。影响固井质量的最低地层孔隙压力因数为１４６。对全井最高地层孔隙压力因数大于１６４的井，在水泥浆中加入了高强度锁水抗窜剂，并配合使用了套管外封隔法进行固井，４０口井的优质率达到９７５％。

Based on the analysis of the laboratary experiment and field data, this paper deals with the physical features of the low permeability and high pressure leyer and the mechanism affacting the quality of well cementing. When annulus pressure is lower than -4.0 MPa and acoustic amplitude is higher than 90%, the channelling will be formed in liquid casing pipe. The least annulus pressure is 1.0 MPa. The lowest formation porosity pressure factor to affect the quality of well cementing is 1.46. For the well whose highest formation porosity pressure factor of the whole well is higher than 1.64 , high intensity antichannel is added to the mud, combined with the method of casing pipe restricted to cement well. In 40 wells cemented by the method, the ratio of the high quality well is 97.5%.