川南香溪群四段低渗裂缝性砂岩储层保护

RESERVOIR PROTECTION OF LOW PERMEABLE FRACTURED SANDSTONES FROM XIANGXI GROUP OF SOUTHERN SICHUAN

陈忠 唐洪明 沈明道 李涛 李其荣 杨茂康

Chen Zhong Tang Hongming Shen Mingdao Li Tao Li Qirong Yang Maokang

川南香溪群四段为一套致密砂岩储层,物性较差,地层水矿化度较高,微裂缝为其主要的运移通道。地层微粒运移、粘土矿物的水化膨胀、泥浆滤液同地层水作用产生的沉淀物等是储层伤害的主要方式。速敏和碱敏实验显示,地层水临界流速最好取1.0ml/min,工作液的临界pH值以10为好。储层岩石与泥浆滤液的长期静态分析表明没有新的物质出现。

The fourth member of Xiangxi Group in southern Sichuan is tight packed and low permeable sandstone reservoir.Its porosity is less than 3.95%,its permeability is lower than 0.25×10 μm.Microfractures are the main passages for gas migration.Formation water minerality is high.Further research proves that formation micronites and drilling fluid precipitates resulted from mud percolate and formation water may plug passages and decrease productivity.The tests of velosity sensitivity and alkali sensitivity suggest that the critical velosity of formation water is better to be 1.0 ml/min;the critical pH value of operating fluid is better to be 10.The long term static analysis of reservoir rock and mud percolate shows that none of new substance appeares.

10.11743/ogg19980415