Application and the Economic Evaluation of New Tools in Fuling Shale Gas Wells

Abstract:

Shale beds of Fuling area contain abundant natural gas resources with good exploration prospect. The main target strata in this block is shale gas bed in upper Ordovician Wufeng formation-the lower part of lower Silurian Longmaxi formation. In the upper shale formation, borehole wall stability is poor and formation pressure bearing capacity is low with karst development as well as collapse and leakage; fluid distribution of marine sedimentary formation is complex, lithology changes in some formations with poor drillability and low ROP. Cluster wells were adopted, but the horizontal wellbore trajectory is complex with large displacement, it was difficult for large directional borehole rectified azimuth and back pressure was serious. New technologies and new tools were used in field experiment, such as rotary steering drilling technology, tortion impacter, rotary impaction motor and hydraulic oscillator, the penetration rate was greatly improved and the drilling cycle was shortened. In this paper, these new technologies and new tools are elaborated in the working principles and field application and the economic effects are evaluated.