欠平衡钻井技术在裂缝性花岗岩油藏开发中的应用

Application of horizontal unbalanced drilling in the development of fractured granite basement reservoir

花岗岩储层特征与常规储层有较大差别,选用合适的钻井技术对降低储层损害、高效开发油田至关重要。也门KHA油田储层属于裂缝性花岗岩基底油藏,欠平衡钻井技术不仅可以克服常规钻井技术因固相侵入产生的储层污染,提高机械钻速,降低钻井液漏失,对保护油气层起到重要的作用,为此在KHA油田应用了欠平衡钻井技术,减少井漏风险,节约钻井成本;通过水平井开发,提高了裂缝钻遇率以及注水井的注入能力和采油井的单井产量;而且还有助于发现新的有效储层,增加油田储量,为油田开发部署和加密调整井提供了重要的参数,从而大幅度地提高了裂缝性花岗岩基底油藏的开发效果。

The drilling technology is very important for the fractured granite basement reservoir to reduce the damage of formation and improve the production because of the large difference of lithology, physical property and other formation characteristics between granite and conventional reservoir. After the ifeld application of the fractured granite basement reservoir in KHA Field of Yemen, the unbalanced drilling can prevent the formation damage caused by the solid phase invasion, improve the penetration rate, reduce the loss of drilling lfuid and protect the hydrocarbon reservoir. It can reduce the risk of lost circulation, and save the drilling cost. The develop-ment of horizontal well can improve fracture drilling ratio, injection capacity of injection well and output of single production well. In addition, it helps to discover new effective reservoir, increase the reserve of oil ifeld and provide important parameters for oilifeld development, deployment, iniflling and adjustment of wells, thus signiifcantly improve the development effect of fractured granite base-ment reservoir.