稠油油藏注蒸汽储层伤害机理及调整措施

Formation damage mechanism and controlling measures for heavy oil reservoir of steam injection

对河南油田稠油油藏地质特征和开发现状进行了分析,利用高温物理模拟实验研究了注蒸汽过程中岩石颗粒的溶解、黏土矿物的溶解及转化、新生矿物的生成、结垢沉淀的产生和注蒸汽后沥青沉积及原油组成的变化引起的储层物性变化。运用铸体和扫描电镜方法,研究了注蒸汽后储层孔隙结构变化特征和物性参数变化规律。在此基础上,分析了稠油油藏注蒸汽过程中的储层伤害机理。根据储层注蒸汽前后物性变化规律提出了治理储层伤害和改善开发效果的技术对策。自2000至2002年,应用治理储层伤害技术对策后,热采区块开发后期累计增油9.413 8×104t,累计油汽比达到了0.36,增油效果显著。

The geological characteristics and development process of heavy oil reservoirs in Henan Oilfield were analyzed. The variations of reservoir properties at high temperature were simulated due to dissolution of rock grains, dissolution and transformation of clay minerals, scaling and precipitation of neogenic minerals, asphalt deposition, and variation of oil components during steam injection. The casting-sample micrograph and scanning electron micrograph were utilized to study the variations of pore structures and reservoir properties after steam injection in the heavy oil reservoirs of Henan Oilfield. The mechanisms of formation damage were in vestigated according to the experimental results. Some measures for controlling formation damage and improving development effec tiveness of reservoirs were proposed according to the variations of reservoir properties before and after steam injection in heavy oil reservoirs. During the application of controlling formation damage technology from 2000 to 2002, the good technical and economic effects have been achieved. The accumulative increment of oil is 9. 413 8 × 10^4 t, and the accumulative oil-steam ratio is 0.36.