Drilling Engineering Design of Well WT-1

Abstract

Well WT-1 is a key exploratory well deployed at Jiangjin district of Chongqing for the exploration of shale gas reservoir with the design depth of 4,900.00 m and designed drilled strata at Ordovician Pagoda formation. Due to the complex situations in this area, there are some technical problems, for example, prediction accuracy of formation pressure is poor, Maokou formation is gas bearing formation with ultra-high pressure, and coal seam and shale bed are easy to collapse. Therefore, the well designing comprehensively adopted conventional casing program design methods, setting position design methods and safety risk assessment technique for casing program design; metal ion polymer drilling fluid system was designed in the upper part, and aluminum amine blocking anti-sloughing drilling fluid system was applied in the lower interval of interest. For well cementing design, conventional cement slurry system was used in the upper part and non-permeable latex channeling preventable slurry system was used in the lower part to improve the quality of cement-formation interface, and two special filter cake curing agents were also used in the design.