八面河油田储层损害机理与保护储层的钻井液技术

STUDY ON MECHANISM OF RESERVOIR DAMAGE AT BAMIANHE OIL FIELD AND THE DRILLING FLUID TECHNOLOGY USED FOR RESERVOIR PROTECTION

利用八面河区块沙河街组储层岩心进行了粘土矿物分析和敏感性实验评价,研究认为八面河区块沙河街组储层渗透率高,粘土含量高,属于强水敏、强盐敏的中高渗储层。在钻井过程中主要的损害因素是钻井液固相侵入和钻井液滤液引起的储层水敏和盐敏性损害。文章针对该储层损害特点,研制开发了无机正电胶双聚钻井液体系,并在25口井上进行了应用,产油量平均提高19%,含水降低6%。室内实验和现场应用表明,该体系兼有正电胶钻井液和聚合醇钻井液的优点,具有独特的流变性、优良的润滑性、稳定井壁作用,以及显著的保护储层功能。

The sensitivity test and clay mineral analysis were conducted with reservoir cores out of Shahejie unit of the Bamianhe Oilfield. The results show that Shahejie reservoir has high permeability, high clay content and can be classified as the reservoir with high water and salt sensitivity. Therefore, the main damage mechanism during well drilling is solids invasion and the water/salt sensitivity damage induced by filtrate. On the basis of reservoir properties, a new drilling and completion fluid named inorganic double-polymer MMH system is developed and applied in 23 wells. The laboratory tests and field applications prove the inorganic double-polymer MMH system not only holds unique rheology, excellent lubricity, wellbore stabilizing capability, formation protection, but also holds the advantages of increasing oil and gas deliverability.