CAJ | 학술논문

松科2井为国际大陆科学钻探计划（ICDP）支持的全球第一口钻穿白垩纪陆相沉积地层的大陆科学钻探井。该井二开（2840 m）钻遇地层中伊蒙混层、伊利石和高岭石等黏土矿物总含量高达60%以上，易水化分散导致缩颈和垮塌；二开上部套管?508 mm，下部井径?215.9 mm，上下两部分井径相差悬殊而导致岩屑返排困难。通过XRD衍射矿物鉴定、室内钻井液材料复配以及现场岩心浸泡等实验分析，优选出适宜于大口径?311.2 mm和?215.9 mm取心工作的低成本钻井液体系。现场应用过程中，钻井液动塑比维持在0.45~0.82 Pa/（mPa·s），润滑系数控制在0.11~0.14，泥饼黏附系数0.12~0.15，有效解决了携岩困难问题，并降低了长裸眼卡钻风险。在大口径取心试验、正式设计取心与全面钻进等作业频繁更换以及钻井液性能不断调整过程中，井内未发生大的坍塌与掉块，圆满完成了在491.12~510.94 m段?311.2 mm口径试取心试验，以及1074.00~1148.01 m和1182.74~1256.01 m段的?215.9 mm口径设计取心任务。
송과2정위국제대륙과학찬탐계화（ICDP）지지적전구제일구찬천백성기륙상침적지층적대륙과학찬탐정。해정이개（2840 m）찬우지층중이몽혼층、이리석화고령석등점토광물총함량고체60%이상，역수화분산도치축경화과탑；이개상부투관?508 mm，하부정경?215.9 mm，상하량부분정경상차현수이도치암설반배곤난。통과XRD연사광물감정、실내찬정액재료복배이급현장암심침포등실험분석，우선출괄의우대구경?311.2 mm화?215.9 mm취심공작적저성본찬정액체계。현장응용과정중，찬정액동소비유지재0.45~0.82 Pa/（mPa·s），윤활계수공제재0.11~0.14，니병점부계수0.12~0.15，유효해결료휴암곤난문제，병강저료장라안잡찬풍험。재대구경취심시험、정식설계취심여전면찬진등작업빈번경환이급찬정액성능불단조정과정중，정내미발생대적담탑여도괴，원만완성료재491.12~510.94 m단?311.2 mm구경시취심시험，이급1074.00~1148.01 m화1182.74~1256.01 m단적?215.9 mm구경설계취심임무。
SK-2 Well, supported by ICDP (International Continental Drilling Program), is the ifrst continental scientiifc exploratory well in the world which penetrates the continental Cretaceous sedimentary formations. In the second spud (2 840 m), the total clay minerals of illite/smectite layer, illite and kaolinite in the formations encountered by the well was up to over 60%, which are easily hydrated, leading to tight hole and collapse. The upper casing in 2nd spud was ?508 mm, and the lower hole size was ?215.9 mm. The large difference between the upper and lower holes led to dififculty in lfowback of cuttings. Through mineral identiifcation by XRD diffraction, indoor compounding of drilling lfuid materials and experiment on ifeld core soaking, the low-cost drilling lfuid system was selected which was applicable to coring in large holes of ?311.2 mm and ?215.9 mm. In ifeld application, the ratio of dynamic shear force of drilling lfuid was maintained at 0.45 to 0.82 Pa/(mPa·s), the lubricating coefifcient was controlled at 0.11 to 0.14, and sticking coefifcient of iflter cake was 0.12 to 0.15, which effectively addressed the problems of carrying cuttings and reduced the risk of stuck pipe in long open hole. No large collapsing and sloughing occurred downhole during frequent alternating of coring test in large hole, formal designed coring and non-coring drilling jobs and during continuous conditioning of drilling lfuid properties, and the experiments of ?311.2 mm core drilling in 491.12 m to 510.94 m and ?215.9 mm core drilling in 1 074.00 m to 1 148.01 m and 1 182.74 m to 1 256.01 m as designed were successfully completed.