重庆涪陵焦石坝地区上部地层岩性致密、研磨性强、可钻性差，长兴组浅层气活跃且含硫，三开水平段长、摩阻大、泥质页岩层易垮塌。钻井面临的突出问题是机械钻速低、井控难度大、钻井周期长。针对上述气藏钻井难点，重点从钻井工艺、维持井壁稳定以及钻井液方面进行分析，优化钻具结构、优选钻头选型、抑制井壁失稳以加快焦石坝区块钻井速度。“油基螺杆＋高效PDC钻头”配合优质钻井液，经过焦页12平台4口井的实践应用，大大缩短了钻井周期，焦页12-4 HF井创下了中石化集团公司非常规页岩气水平井最长水平段记录，提速效果显著。

There are the characteristics of dense lithology, strong abrasive and poor drillability in upper formaton in Jiaoshi-ba area of Chongqing, active shallow gas with sulfur in Changxin formation and long third spud horizontal section, high fric-tion and being easy to collapse in clay shale.The prominent problems were low ROP, difficult well control and long drilling cycle.According to the above difficulties in gas reservoir drilling, the analysis was made mainly on the drilling technology, wellbore stability maintenance and drilling fluid;optimization of drilling tool structure, optimizing bit selection, inhibition of wellbore instability were carried out in order to speed up the drilling speed in Jiaoshiba area.“Screw drill +high effi-cient PDC bit” with high-quality drilling fluid were applied in 4 wells of the 12th drilling platform and the drilling cycle was greatly shortened.The construction of Jiaoye 12-4HF sets the record of the longest horizontal section in unconventio

目前页岩气水平井压裂后排采主要依靠现场经验,规律性不强。为此,通过挖掘气藏数值模型的功能,并结合井筒流动模型,初步研究了页岩气水平井分段压裂排采规律。基于正交设计原理,考虑了页岩基质参数、裂缝参数及生产参数等13个影响因素。结果表明,影响压后返排率的因素按影响程度排序依次为破胶液黏度、压力系数、井底流压、段数、单段注入量、裂缝半长、日排液量、返排时机、导流能力、束缚水饱和度、裂缝形态、裂缝支撑剖面和吸附气含量。为了取得最好的压裂后排采效果,上述不可控参数可作为选井、选段的重要依据,而可控参数可用来对压裂施工参数进行优化调整。该成果已在涪陵焦石坝区块的页岩气水平井压裂中成功应用,压裂后排采效果显著,多口应用井压裂后获得10×104 m3/d以上的产量,且稳产前景良好。

At present ,flowback management after fracturing of shale gas horizontal wells mainly de-pends on field experience .By combining gas reservoir simulation model and wellbore flow model ,multistage fracturing flowback pattern of shale gas horizontal wells was simulated preliminarily .Based on the orthogo-nal design method ,13 factors including rock matrix ,fracture ,and production are taken into consideration . T he results indicate that the factors affecting flow back recovery rank in descending sequence as viscosity of gel breaking fluid ,pressure coefficient ,bottom hole flowing pressure ,total stages ,fluid volume injected per stage ,half fracture length ,flowback rate ,flowback time ,fracture conductivity ,irreducible water saturation , fracture shape ,propped fracture profile ,and adsorption gas content .To optimize flowback effect ,controlla-ble factors among those mentioned above can be used to adjust fracture treatment parameters ,and the un-controllable factors can be used in w