The Study Of Fracture Mode In Outcrop Of Carbonate Rock Of Maokou Formation On Sangmuchang Structural Zone

Sichuan province have two large gas company,the CNPC Southwest Fields Company and the Sinopec Chishui Fields company. The main pay formation of gas reservoir is carbonate rock of qixia formation and maokou formation which develop in Sichuan basin. Structure fracture and corrosion cave are main reservoir space of carbonate reservoir.The reservoirs are fracture type and fractured-vuggy type.Based on the study of the outcropping fracture characteristics,we can analyzed the fractured modle of different tectonic position and relationship beteween fault and derived farcture as well.Through obversation 89 outcrops,the text completed the stripping fractured data,then classify and grade the stress character,extension,width,filling compound of fracture.Analyzed the fracture of same tectonic position,studied the matching form and grouping pattern of farcture.Analyzed the different kinds fault and derived fracuture,then find the relationship of them. Compared the fracture of different tectonic position, we find tectonic curvature,tectonic position and fault are main factors which control develop level of fracture in study region.Substage and mating fracture by cut,confine and filling level data. Combined with former study of fracture modle,we conclude the fracture net modle on three-dimensional space(the array mode of varying measure and difference attitude). For example:(1) Shear fracture net mode in anticlinal flank.(2) Gash fracture net mode in anticlinal core.(3) Compression fissure net mode.After study,we know that:(1) Different orientation fault and fracture which undergo multiple phase of tectonic movement make up fracture net.(2) Structure scope control the size of fracture.fracture in samall scale anticline showing brief extension,trivial cut and large width. ?(3) The fracture of anticlinal flank consists of shear fracture and gash fracture ,but shear fracture accounts for the main part. But the number of shear fracture is equal to the number of gash fracture in anticlinal core.(4) In anticlinal core and flank,shear fracture which created by fold modify showing brief extension,narrow and high density.But gash fracture which created by fracturing showing long extension,braod and low density.