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分支井技术可以从一个主井眼中钻成多个相互独立的、可以再次进入的、具有压力封隔效果的分支井，并能进行完井作业。新浅90分支井是由西南石油局设计并施工的中国国内第一口天然气分支并，并在国内首次进行加砂压裂并获圆满成功，也是我国第一口达到TAML五级标准的分支井。该井在吸收国内外成功经验的基础上，研究出了一套适合于气井作业的分支井钻井完井配套工艺技术。结合川西地区气井多产层、高压力梯度、河道砂体岩性变化大等地质特点，该井组主井眼和分支井眼均采用套管固井、射孔完成，通过双油管和双封隔器的完井管柱实现了主井眼和分支井眼的层间压力分隔和分井压裂、分井采气。

Design and Operating Techniques of the First Gas Branch Hole in China

Several branch holes,which are mutually independent,can be reenterable and have pressure seal effects,may be drilled through a main well and their completion operations can be carried out by applying branch hole techniques.Well Xinqian 90 is the first gas branch hole in China designed and constructed by the Southwest Petroleum Bureau,the first sand fracturing was successfully made in the hole and it is also the first branch hole of attaining to TAML 5 grade standard in our country.A series of techniques suitable for the drilling and completion of the gas branch hole were studied out on the basis of assimilating domestic and foreign successful experiences.In combination with the geological features of the gas wells in West Sichuan,such as multi payzone,high pressure gradients and a large lithological change in channel sand bodies,etc.,the casing cementing and perforation completion were adopted for the main well and branch holes in the well group and the interzonal pressure seals of the main well and branch holes,and the separate well fracturing and producing were all realized through a completion string with dual tubing and dual packer.