复杂岩性油气勘探保护储层新技术

介绍了胜利油田复杂岩性油气勘探保护油层的新技术。即探井储集层敏感性预测技术、复杂岩性储集层保护钻井液技术、根据油气上返速度调整钻井液密度解放储层。敏感性预测技术是根据数据库文件,得出该样品的速敏、盐敏、水敏、酸敏、碱敏伤害率等详细预测报告。为制定单井油气层保护措施提供依据。对于松散砂岩储层采用一步法钻井液、PAM-MMH钻井液和MEG-MMH钻井液技术;对于水敏性较强的储层采用聚合醇钻井液、钙醇络合水基钻井液和MEG钻井液;对于裂缝、孔洞储集层采用无粘土相钻井液和抗高温无粘土低固相钻井液技术。这几套钻井液体系有针对性地解决了复杂岩性油气勘探井壁稳定、润滑、毒性及保护储层等问题。在钻探井的过程中根据油气上窜速度的大小及时调整钻井液相对密度。做到了压而不死、活而不喷,最大限度地发现和保护了油气层。对于主要含油层的沙河街组的沙一段．沙三段和沙四段地层,控制一定的油气上返速度,始终保持油气处于“亚活跃”状态,对减少钻井液伤害,保护好油气层取得很好的效果。

New technologies on reservoir protection in complex reservoir exploration

The new technologies presented in this paper include formation sensitivity prediction technology in the exploratory well, drilling fluid technology for complex reservoir protection, and drilling fluid density adjustment technology according to the up-return velocity of oil and gas. The sensitivity prediction tech nology can present the detailed predicting reports on velocity sensitivity, salt sensitivity, water sensitivity, acid sensitivity, and alkali sensitivity, etc. , based on the database files, and provide the backups for making out the specific measures for each well. For the loose sand rock reservoir, use the so called "one-step" drilling fluid, PAM-MMH drilling fluid and MEG-MMH drilling fluid; use polyol drilling fluid, calcium-alcohol complexing water based drilling fluid and MEG drilling fluid for the water sensitive reservoir; and for fractured and porous formation, use clay free drilling fluid and high temperature tolerant clay free and low solids drilling fluid. These drilling fluid systems effectively solve such problems as wellbore stability, lubricity, toxicity and formation damages in complex reservoir exploration. During drilling of the explora- tory well, adjust the drilling fluid density according to the up-return velocity of oil and gas timely, thus maximize the oil and gas discovery and minimize formation damage. When drilling the main reservoirs in Shengli Oilfield, by adjusting the up-return velocity, the oil and gas was kept in a sub-active state, and this minimized drilling fluid damage and effectively protected the reservoirs.