流体pH值对致密砂岩储层渗透率的影响  

INFLUENCE OF FLUID pH ON THE PERMEABILITY OF TIGHT SANDSTONE RESERVOIR

作　　者：杨建[1] 康毅力[1] 兰林[1] 胡永东[2] 陈家明[2] 

机构地区：[1]"油气藏地质及开发工程"国家重点实验室.西南石油学院 [2]中国石油西南油气田分公司川中油气矿

出　　处：《天然气工业》2005年第10期33-35,共3页Natural Gas Industry

摘　　要：地层流体pH值一般分布在4～9范围,一旦侵入储层的流体pH值过高或过低,将引发外来流体与储层流体、储层矿物不配伍的问题,必然造成储层损害。文章以川中香溪群致密砂岩气层为例,开展流体pH值逐级升高和pH值逐级降低对储层渗透率改变的综合评价实验。实验表明,储层具有强碱敏、强的HCl酸敏感性。研究指出,高pH值流体条件诱发粘土矿物微结构的破坏,导致伊利石、绿泥石等粘土矿物溶解、脱落、分散(运移),渗透率大幅度下降;低pH值流体破坏绿泥石的晶体结构,使结构中的Fe2+、Fe3+、Mg2+等离子析出,产生Fe(OH)3以及Mg(OH)2沉淀,堵塞喉道。The rang of stratum fluid pH is from 4 to 9 in general. Once the pH of the fluid invading reservoir is too high or too low, it is inevitably happened that invasion fluid not matches with reservoir fluid and mineral so as to cause reservoir damage. Taking the tight sandstone reservoir of Xianxiqun Formation as an example, the comprehensive evaluation experiment of changing the reservoir permeability by gradually increasing or decreasing fluid pH is carried out and the result shows the clay mineral microstructure damage caused by high pH makes the clay minerals such as illite and chlorite etc. dissolve, disperse, migrate and decrease, the permeability; low pH fluid can destroy the crystal microstructure of chlorite, which makes the Fe2+, Fe3+, Mg2+ within the structure separate to cause Fe(OH)3 and Mg (OH)2 deposit and plug up pore throat.

关 键 词：PH值 致密砂岩 储集层 保护 粘土矿物 四川盆地 中部 储层渗透率 地层流体 高PH值 

分 类 号：P618.13[天文地球—矿床学]