摘要
随着常规天然气资源的减少,深层致密砂岩气藏将成为天然气勘探开发的热点。然而致密砂岩气藏具有低孔低渗、黏土矿物丰富多样、裂缝发育等工程地质特征,在作业过程中储层易受损害,气井的产能远远低于预期值。为此,选取川西大邑构造T3x3致密砂岩岩样,采用逐渐增大压力梯度的速敏实验新方法,开展了室温20℃与高温120℃条件下裂缝岩样的速敏与碱敏实验。实验结果表明,室温储层速敏程度为中偏弱～中偏强,高温为强;室温储层碱敏程度为无～弱,高温为中偏弱～强,储层高温流体敏感性明显地强于室温流体敏感性。分析指出,矿物热膨胀、岩石表面性质改变、矿物溶解度及溶解速率增大、外来流体与储层矿物的反应速率增加导致微粒分散运移加剧等是高温流体敏感性增强的主要原因。
With the dwindling of conventional gas reservoirs,deep tight sandstone gas reservoirs will become a hot spot of natural gas exploration and development. However,tight sandstone gas res-ervoirs display such characteristics as low porosity and permeability,natural fractures developed and abundant clay components. What is more,it is liable to be damaged during operation,and the gas well productivity is far lower than expected. With the fractured cores from tight sandstone reservoir in western Sichuan,fluid sensitivity experi-ments under high temperature and normal temperature were conduc-ted. In addition,a new method,increasing the pressure gradient gradually,was proposed to evaluate velocity-sensitivity. The result showed that velocity-sensitive was medium weak to medium strong under normal temperature,and strong under high temperature; alkali-sensitive was none to weak under normal temperature,and medi-um weak to strong under high temperature. High temperature sensi-tivity was stronger than normal temperature sensitivity. Analysis of formation damage mechanism showed that mineral expansion,change of surface properties of reservoir rock,mineral solubility and reactionrate increment between external working fluid and reservoir mineral account for sensitivity enhancement under high temperature.
出处
《钻采工艺》
CAS
北大核心
2010年第4期83-86,93,共5页
Drilling & Production Technology
基金
国家科技重大专项(2008ZX05022-004-04HZ
2008ZX05045-003-01)
四川省杰出青年学科带头人培养基金项目(07ZQ026-113)
博士后基金项目(20070411164
20090451422)
关键词
致密砂岩
气藏
高温
裂缝
敏感性
tight sandstone,gas reservoir,high temperature,fracture,sensitivity
