低压低渗透气田Ø139.7 mm套管开窗侧钻水平井钻井液技术

Drilling fluid technology for sidetracking horizontal wells withØ139.7 mm casing windows in low-pressure and low-permeability gas fields

苏里格气田属于低压低渗透气田,部分常规井已失去开采价值,实施Ø139.7 mm套管开窗侧钻水平井有助于老井恢复新的采气能力,与常规井眼相比,Ø139.7 mm套管开窗侧钻水平井井眼存在润滑防卡、水平段泥岩坍塌、窄环空间隙易漏失等技术难点。研制了强抑制、强封堵CQSP-4钻井液体系,并对其流变性、防塌性、抑制性、润滑性进行了室内评价,实验表明,100℃、12h岩屑滚动回收率达95.63%,100℃热滚24 h后API滤失量2.8 mL、高温高压滤失量13.2 mL,抗钻屑污染能力高达14%。对开窗侧钻、裸眼段钻进、钻井液固相控制、防漏、降摩减阻、井眼清洁等钻井液工艺进行了优化,截至2022年12月共进行了18口井现场应用,钻井周期较2017-2018年降低69.58%,机械钻速提高了102.82%,平均钻井周期由之前的80.5 d降至24.49 d,达到了提速提效的目的。该技术可为国内其他地区同类井施工提供借鉴。

Sulige Gas Field presents low-pressure and low-permeability features.Production of some wells with traditional technology is unprofitable.Implementing drilling fluid technology for sidetracking horizontal wells withØ139.7 mm casing windows is beneficial for the recovery of abandoned wells.Compared to conventional wellbores,the sidetracking horizontal wells withØ139.7 mm casing windows face technical challenges such as lubrication,anti-sticking,mudstone collapse in the horizontal section and leaking in narrow annular spaces.Therefore,a CQSP-4 drilling fluid system,with strong inhibition and powerful sealing capacity,was developed.And,the rheological,anti-collapse,inhibitive,and lubricating properties of the drilling fluid system were evaluated indoor.The experiments showed that the cuttings rolling recovery rate reached 95.63%after 12 h at 100℃,and after 24 hours of hot rolling at 100℃,API filtration loss was 2.8 mL,and the high-temperature and high-pressure filtration loss was 13.2 mL,with a high resistance to cuttings contamination up to 14%.Furthermore,drilling fluid processes such as casing window sidetracking,open-hole section drilling,solid phase control,leak prevention,friction reduction and hole cleaning were optimized.As of December 2022,a total of 18 wells had been field-tested.The drilling cycle reduced by 69.58%compared to 2017-2018,the rate of penetration increased by 102.82%,and the average drilling cycle decreased from 80.5 days to 24.49 days,achieving the goal of speeding up and improving efficiency.This technology has a guiding significance for the construction of similar wells in other regions at home.