YD油田高渗灰岩储层水平井钻井液技术

YD油田水平井在高渗灰岩储层钻井过程中,存在井壁失稳、盐膏污染钻井液、井漏、井眼清洁效果差和摩阻高等技术难点.为解决这些技术难点,通过室内实验,优选了流性调控剂、抗盐降滤失剂,确定了复合润滑剂配方和封堵材料的组成,形成了强抑制高封堵乳液聚合物钻井液,并针对各开次钻遇地层的地质特征制定了钻井液维护与处理技术措施.性能评价表明,泥页岩在强抑制高封堵乳液聚合物钻井液中的滚动回收率达88.2%,线性膨胀率为18.2%;能抗5.0%NaCl、2.0%CaSO4和30%钻屑的污染,具有较好的防塌抑制效果与抗污染能力.该钻井液在YD油田S4井、S5井和S16井等3口水平井中进行了应用,钻井过程钻井液性能稳定,钻井施工顺利.与该油田其他22口水平井相比,钻井周期分别缩短5.2,6.3和7.8 d,渗漏量分别降低了12.5%,8.4%和13.2%,最大提升和下放阻力降低到150 kN之内.现场应用表明,强抑制高封堵乳液聚合物钻井液能有效解决YD油田高渗灰岩地层水平井钻井液技术难点,可以在该油田进行推广. 

Fluid Technology for Drilling Horizontal Wells in the High Permeability Carbonate Reservoir of the YD Oilfield

During horizontal well drilling in high permeability carbonate reservoir of the YD Oilfield, many challenges were encountered, such as borehole instability, salt and gypsum contamination, lost circulation, poor hole cleaning, and high friction drag. In order to solve these problems, laboratory experiments have been done to optimize fluidity regulator, anti-salt filtrate reducer, complex lubricant formula and plugging materials, and then emulsion polymer drilling fluid with strong inhibition and good plugging property was developed. Moreover, drilling fluid maintenance technique for every formation with different geologic feature has been conducted. With the application of the developed drilling fluid, shale rolling recovery rate could get 88.2%, its linear expansion rate could get 18.2%, and 5.0% NaCl or 2.0% CaSO4 or 30% drilling cuttings contamination could be resisted,which showed that the developed drilling fluid has strong anti-sloughing function and good resistance to contamination.The drilling fluids have been applied in three horizontal wells in the YD Oilfield, including Well S4, Well S5 and Well S16, and kept stable performance in drilling operation.Compared with 22 offset wells, the drilling duration of these three wells has been reduced by 5.2 d, 6.3 d and 7.8 d respectively, the leakage volume has been reduced by 12.5%, 8.4% and 13.2% respectively, and the resistance while RIH and POOH can be less than 150kN. The application results show that the developed drilling fluid can solve horizontal drilling problem in carbonate formations with high permeability, and can be used widely in the YD Oilfield in the future.