厄瓜多尔Tarapoa区块上部地层沉积时间短,地层较新,欠压实,在钻井施工时易发生井壁失稳,引起泥包、造浆等问题.为解决此问题,利用钙离子絮凝、抑制的特点,结合物理封堵研究了钙基强封堵钻井液体系.室内评价结果表明,钙基强封堵钻井液配方一次回收率达到88.28％,黏土岩心膨胀量仅为4.287 mm,岩心封堵率95％ 以上,抗黏土污染大于10％,具有絮凝钻屑、抑制性强、封堵性作用良好和抗钻屑污染高等特点.在Tarapoa区块应用十多口井,钙基强封堵钻井液防塌作用明显,密度易控,流变性能稳定,解决了该区块上部地层钻井液技术难点,提高了机械钻速,保证了起下钻顺畅,下套管安全到位,完全满足厄瓜多尔上部地层安全钻进的需要.

应用渗透性封堵仪对封堵剂进行了性能评价,封堵剂能够显著降低钻井液的瞬时滤失量,有利于钻井液在磨砂盘表面形成光滑致密泥饼,降低滤液的侵入.

厄瓜多尔TARAPOA区块大斜度井段经常出现高摩阻大扭矩、遏阻现象频发、卡钻时有发生,并且在大斜度井段出现的卡钻,没有成功解卡的先例;再加上井身结构的进一步简化和环保条款的硬性规定,使得大斜度井段施工难度进一步加大.针对上述难题,在厄瓜多尔政府环保要求的基础上,选择有利于环保处理剂,研制出了一种性能稳定、防塌能力突出、润滑性好、携砂能力强、环保性能理想等特点的GAP钻井液体系.现场应用结果表明,该体系表现出良好的井壁稳定能力、润滑减阻和井眼净化能力,有效解决了泥页岩和砾石层所带来的的缩径扩径、坍塌掉块、高摩阻大扭矩、钻头泥包等技术难题,在整个斜井段施工过程中井壁稳定,起下钻畅通无阻,首次将3 133 m长的(O)244.4 mm技术套管一次性下到预定位置.

靖平69－12井目的层马五1－3，埋藏深度3700 m，属长南气田第一口三开结构水平井，刘家沟组漏层和“双石”层与山西组、太原组以及本溪组等煤层处于同一裸眼井段，裸眼段长，防漏与防塌的安全密度窗口窄，是典型的塌漏同段井。针对该区块地层特点，研制出了抑制性强、封堵性好等特点的强抑制成膜封堵钻井液体系。现场应用结果表明，该体系表现出良好的抑制防塌性、润滑防卡性和成膜封堵特性，滤饼薄而韧。在整个斜井段施工过程中井壁稳定，起下钻不阻不卡，克服了上部裸眼段长时间浸泡所带来的井壁不稳定风险，防止了地层漏失，解决了长裸眼段下存在的井壁坍塌、润滑防卡等技术难题，保证了3460 m多的长裸眼井段的井眼稳定和177．8 mm技术套管一次性下到预定位置。

长北气田本着安全环保的理念，近年来不断重复使用低伤害钻完井液（DIF），使得一些不易清除的黏土颗粒不断在钻井液中积累，导致钻井液中分散黏土含量（MBT）不断升高，在液柱的高压差下，使钻井液中分散很细的黏土微粒进入储层，使储层孔隙进一步缩小，水锁加剧，导致产量降低。针对这一难题，主要从改变储层表面性质着手，研制出了洗井液NDF－1，该洗井液使低渗砂岩气藏由强亲水变为弱亲水，消除储层毛管力，溶解进入部分固相，拆散堵塞，从而提高气驱水效率，消除固相伤害。室内试验表明，洗井液NDF－1可以使现场DIF伤害后岩心渗透率恢复率得到明显提高，效果优于酸液，并且可以完全克服室内配制DIF钻井液给岩心造成的伤害。

厄瓜多尔SACHA区块φ215.9 mm井段在钻井过程中经常出现钻头泥包、井壁坍塌、起下钻遏阻、测井和下尾管阻卡等问题,在分析原因的基础上,选择有利于环保的有机抑制剂SUPHIB、半透膜剂MS和隔离膜剂EX等材料,优选出微乳液强抑制强封堵钻井液配方,并通过室内试验评价了其性能,结果表明:该钻井液在100℃条件下热滚16h后仍具有良好的基本性能;具有良好的抑制性能和封堵性能,对TENA层岩屑的回收率达到90％以上,膨胀率仅有1.32％,对高孔高渗储层岩心的封堵率达到99％.微乳液强抑制强封堵钻井液已经在厄瓜多尔SACHA区块的8口井进行了应用,均没有出现钻头泥包、起下钻遏阻、测井和下尾管阻卡等问题,且φ215.9 mrn井段平均井径扩大率降至10％以下.这表明,微乳液强抑制强封堵钻井液能够有效解决厄瓜多尔SACHA区块φ215.9 mm井段的一系列井下复杂问题.

针对长庆地区致密气藏水平井钻井过程中的长井段泥岩/炭质泥岩垮塌、长时间钻井液浸泡、裸眼井段筛管甚至裸眼直接完井带来的储层保护技术难题,室内研发了伤害度低的暂堵型水平井钻井液完井液体系,并在长北气田29余口、长庆油田内部80口裸眼完井或筛管完井的多分支水平井成功应用.

苏里格分支水平井难度最大的地方在于分支井眼,分支井眼首次将大斜度井段和水平段设计为全裸眼,针对苏里格气田分支井眼斜井段和水平段处于同一裸眼段的技术难题,室内研发了强抑制性有机-无机盐低伤害钻井（完井）液体系,并在桃7-14-18H分支井和桃7-15-20H分支井的分支井眼成功试验应用.室内和现场试验结果表明,该体系能有效解决气井水平井斜井段和水平段同处于裸眼段情况下的的泥页岩井壁失稳、气层保护、高摩阻大扭矩、井眼净化、携砂悬砂等一系列技术难题.该体系抑制性强,其页岩一次回收率达到了97.2％,二次回收率达90.3％;体系利于保护产层,对盒7和盒8产层岩心的平均伤害率为10.60％,属于低伤害.钻井液优良的综合性能保障了1742m装有裸眼封隔器的套管完井管串直接穿越裸眼斜井段安全下至水平段的预定位置.

神木双山区块水平井首次采用三开井身结构,二开裸眼井段将长达2 400 m,在这一井段地层极易出现缩、卡、漏、垮塌等复杂,针对上述技术难题,优选出了安全快速钻进钻井液体系,并在神木双山区块应用了2口井.实验表明,该体系表现出良好的润滑防卡性和良好的井眼净化能力,性能易调控、低滤失、高黏度切力,泥饼薄而韧.在整个斜井段施工过程中,2口井井眼始终处于良好净化状态,起下钻无阻卡,井底无沉砂,很好地解决了长裸眼段下存在的井壁坍塌、润滑防卡、携带岩屑等技术难题,把二开钻井周期缩短到20 d以内,而且确保了12h把φ177.8 mm技术套管安全顺利下至井深2 890 m,创造了长庆水平井下技术套管时间最短的新记录.

鄂尔多斯盆地长庆气区储气库选择在榆林气田的山西组山23储层实施,由于该气层经过长期开采和储层压裂改造,导致水平段目的层压力极低(压力系数0.4～0.6),成为诱发水平井段发生钻井液压差漏失的地质因素；且采用筛管完井方式又要求钻井液完井液必须具有非常好的暂堵效果.针对上述技术难题,以室内预防井漏、储层保护研究为技术支撑,研制出了具有抑制性强、润滑性高、总固相少等特点的无土相复合盐低伤害暂堵钻井液完井液体系.现场应用两口井,其中Y37-2H完钻井深5 044 m,水平段长1 819 m,创长庆气田水平段Φ215.9 mm井眼的施工记录,Φ139.7 mm筛管一次性下到预定位置,并获得无阻流量100×104 m3/d的高产气流.应用效果表明:该体系较好地保护了山23储层,钻完井施工作业安全顺利.

The Changqing underground gas storage well is to be completed at the Shan 2 3 reservoir in the Yulin Gas Field of the Changqing gas zone, Ordos Basin. Due to the long-time production and fracturing stimulation, the pressure at the pay zone of the horizontal well is extremely low with the pressure coefficient of only 0.4 - 0.6, which becomes a geological factor leading to lost circulation when the horizontal section is drilled. Apart from that, to meet the needs of the designed work of screen liner completion, the drilling and completion fluid should have very good plugging performance. In view of this, an experimental study is conducted to find ways to avoid lost circulation and provide reservoir protection in terms of drilling and completion fluid technology, thus, a low-damage and non-clay composite salt system is developed with high inhibition, high lubricity, low solids content, and temporary plugging capability. It has been applied in 2 wells, the well Y37-2H of which was drilled and completed with a total depth of 5044 m and a horizontal section length of 1819 m, thus, a new record of the length was set up for the 0215.9 mm horizontal well drilling in the Changqing Gas Field. As a result, the 0139.7 mm liner was smoothly run to the predetermined depth without any problem. And the potential flow rate was high up to 1 million m 3 per day. This field application shows that this system can not only effectively protect the Shan 2 3 reservoir but make a safe drilling and completion job possible.

Y37-2H with a total depth of 5044 m and a horizontal section of 1819 m is the first pilot test horizontal well in the Yulin gas storage under the National Gas Storage Reservoir Project.The injection and production well of storage reservoir requires strong working capacity of 50×104-100×104m3/d and a service life of at least 50 years.In view of this,the following technologies are developed to perform the intensified injection and production functions on the basis of a thorough analysis of the production of this pilot gas well.First,a φ215.9 mm borehole is employed in the long horizontal section drilling,and φ139.7 mm screen pipes for well completion.Second,a long-radius horizontal well profile is carefully selected,the advanced technique of geo-steering with drilling is applied in reservoir tracing,and the rate of overall angle change of the horizontal section borehole is controlled not to be more than 4°/30m,therefore meeting the quality requirements of cementing and casing for hole trajectory.Third,the pressure pulse,as a result of drilling fluid flowing through hydro-oscillator,drives the drilling rig to generate mild vibration that transforms the static friction between the drilling rig and the borehole into kinetic friction,thus,effectively reducing friction drag and torque,and improving the weight on bit transfer and the ROP of slide drilling and the footage on horizontal sections.Fourth,a clay-free composite salt and low-damage temporary plugging drilling(well completion) fluid system is applied and proved to be helpful for the Shan23 reservoir protection and to meet the requirements of lubrication and anti-clamp of long horizontal well sections and anti-collapse of mudstones.In general,the drilling of this well serves as a technical basis for the construction of super-large storage reservoir in the Changqing Gas Field.

Changbei gasfield belongs to tight gas reservoir. In the drilling process, the invasion of drilling fluids is one of the main reservoir damage factors. To reduce the invasion of drilling and completion fluids, studies were mainly focus on temporary plugging and wettability change of reservoir rock surface, and a type of NDW clay-free low damage drilling fluid was developed. The fluid had effective protection for gas reservoir because its average damage ratio to the pay-zone is only 11.25%, tested under reservoir conditions. The fliud had good temporary plugging, excellent inhibitive ability and high lubricity. In the whole drilling of horizontal interval in well CB8-3, the cumulative horizontal interval length using the fluid is 4 388 m, and the borehole is always kept clean, with no blockage and no pipe-sticking during tripping, and no sand setting in downhole. Moreover, more than 240 m shale was stable and the production of 230×104 m3/d in this well was obtained, which created the new record of highest individual production rate in onshore low permeability gasfield in China.

针对苏里格地区低孔低渗砂岩气藏的特点,依据ASS-1全酸溶钻井（完井）液在该地区探井的应用经验,研制出了复合盐水低伤害钻井完井液。该钻井液在常规条件下对地层的平均伤害率仅为5.9%,在特殊模拟井下条件下,对气层的平均伤害率为13.64%,暂堵性好,井壁上形成的暂堵滤饼通过气层压力完成解堵,简化了完井、投产作业。该钻井液在桃7-9-5AH井水平段施工过程中,起下钻无阻卡,井底无沉砂,解决了因泥页岩水化膨胀而引起的缩径和坍塌、高摩阻大扭矩、PDC钻头泥包等一系列技术难题,创造了长庆区块水平段一只φ152.4 mm钻头810 m进尺的记录,并获得无阻流量150×104 m3/d的高产气流。

The target zone of drilling at the Tao7 Block of the Sulige Gas Field in the Ordors Basin is the 7th member of the Permian Shihezi Formation.Water swelling will easily occur in the formations of Shiqianfeng and Shihezi(called "Double-Shi Formation" for short) in this area,resulting in wellbore instability and bit balling,etc..In view of this,experimental studies were conducted,with the inhibition,lubricity and rheological properties taken into account,and two drilling fluid systems were developed: a potassium salt poly-sulfonate drilling fluid system and a strongly inhibitive and low-damage temporary-sealing drilling fluid system.The application of both them in the horizontal well Tao7-17-19H achieves good results.The potassium salt polysulfonate drilling fluid used in the deviated interval has good performance in inhibition and hole cleaning,smoothly resolving downhole problems like hole shrinkage,hole enlargement,sloughing and caving,high drag and torque and bit balling caused by the hydration swelling in shale formations.The strongly inhibitive low-damage temporary-sealing drilling fluid system used in the 3rd spud-in horizontal section have many advantages like stable performance,low water loss,good lubricity,remarkable temporary-sealing effects,and effective protection of the reservoir.As a result,the horizontal well Tao7-17-19H was drilled and completed with a total depth of 4360 m,a horizontal section of 900 m,a drilling cycle of 39.25 days,and an open flow capacity of 108×104m3/d.The application reveals that these two developed drilling fluid systems are adaptable to the well Tao7-17-19H,meeting the drilling requirements without any accidents,the most important of all,the penetration rate of this well is significantly increased,and the shortest horizontal well drilling cycle is also obtained as a record in the Sulige Gas Field.