有机盐-聚合物钻井液在北部湾大斜度井中的应用

Application of Organic Salt Polymer Drilling Fluid in Highly Deviated Wells in Beibu Gulf

南海北部湾盆地涠洲某油田目的层位于涠三段和流一段,前期已钻六口开发井,后期为动用流一段Ⅴ油组储量,决定部署两口大斜度调整井,井斜均大于80°,且裸眼段较长。流一段平均孔隙度19.3%,平均渗透率3405md,属于中孔高渗储层,为更好的保护储层,经室内试验和配方优选,形成了一套新型低密度无固相有机盐-聚合物钻井液体系,并在两口大斜度调整井中应用。现场应用表明,该体系携岩性好,抑制性强,储层保护效果好,为南海西部类似油田的开发积累了宝贵的经验。

The target layer of an oil field in Weizhou, Beibu Gulf Basin in the west of the South China Sea is located in Weisan member and Liuyi member. In the early stage, six development wells have been drilled. In the later stage, the reserves of oil formation V in Liuyi member have been utilized. It is decided to drill two high inclination adjustment wells, with well inclination greater than 80° and long open hole section. The average porosity of the first section of Liuhe formation is 19.3 % and the average permeability is 3405 md. It belongs to a medium porosity and high permeability reservoir. In order to better protect the reservoir, a new low-density solid-free organic salt polymer drilling fluid system has been formed through laboratory tests and formulation optimization, and has been applied in two high-angle adjustment wells in the west of the South China Sea. Field application shows that the system has good lithology, strong inhibition and good reservoir protection effect, which has accumulated valuable experience for the development of similar oil fields in the west of the South China Sea.