聚胺钙盐润滑防塌钻井液在胜利单18区块的应用

Polyamine calcium salt drilling fluid with lubricating and anti-collapse functions and its application to Shan 18 block,Shengli oilfield

单18区块位于济阳坳陷东营凹陷滨县陡坡构造带。为提高该区块勘探开发效率及效益,保证钻井过程中井壁稳定,针对该区块地层岩性特点及施工中钻井液技术难点,确定了强抑制、强封堵、活度平衡三元协同稳定井壁钻井液技术思路,据此优选胺基聚醇、多级配封堵剂及氯化钙等钻井液处理剂,研发了聚胺钙盐润滑防塌钻井液体系。评价实验表明,该体系流变性及润滑性好,抑制性及封堵性强,能够满足定向钻井的要求。聚胺钙盐润滑防塌钻井液体系在单18区块8口井进行了现场应用,应用结果表明:(1)辅助现场钻井液施工工艺,满足了工程上安全顺利钻井的需求,体系应用井钻进过程中井壁稳定,解决了沙河街组油泥岩水化失稳和砂岩地层孔缝失稳而导致的井壁坍塌问题;(2)体系应用井的井眼净化效果好,定向过程中摩阻和扭矩低,解决了该区块定向过程中存在的润滑防卡难题;(3)体系应用井和前期已完钻井相比,平均完井周期缩短27.08%,平均机械钻速提高23.23%,平均井径扩大率降低了34.82%,更好地达成了优质高效钻井的目标。

Shan 18 block is located in Binxian steep-slope structural belt,Dongying sag,Jiyang depression.In order to improve its exploration and development efficiency and benefits in this block as well as ensure wellbore stability,a technical idea for stabilizing drilling fluid at the wellbore was proposed through a three-element(strong inhibition,strong plugging and activity balance)cooperation with regard to natures in formation lithology and technical difficulties in drilling-fluid operation.Accordingly,treatment agents of drilling fluid like amino polyalcohol,multi-graded plugging agent and calcium chloride were selected to prepare the polyamine calcium salt drilling-fluid system with lubricating and anti-collapsing functions.Evaluation experiments show that,this system boasts good rheology and lubricity,strong inhibition and plugging performance,meeting requirements of directional drilling.Moreover,it has been applied to 8 wells in this block.Application results reveal that(i)the system can assist on-site drilling-fluid operation to ensure safe and smooth drilling with stable wellbore,thus avoiding wellbore collapse due to instability in sandstone of Shahejie Formation induced from oil-shale hydration and coexistence of pores and fractures;(ii)better hole cleaning effects and low friction and torque can be achieved in those wells employed the polyamine calcium salt drilling-fluid system during the directional drilling without lubricating and anti-sticking problems occurred;and(iii)compared with the other drilled wells,the average completion period reduces by 27.08%for the wells employed the polyamine calcium salt drilling-fluid system,the average ROP enhanced by 23.23%,and the average hole enlargement rate decreased by 34.82%,indicating a better performance in quality and efficient drilling.