Shunan The Eastern Part Of The Sedimentary Facies Of The Triassic Feixianguan And Favorable Reservoir Facies Prediction,

We put our hands to the characters of sedimentary petrography and lithogenesis of the Feixianguan Formation, applied the theory such as sedimentology, reservoir geology and structural geology, firstly studied the sedimentary fades, diagenetic facies and structural evolution of the Feixianguan Formation in the eastern part of Shunan area, analysed the formation, evolution and distribution of the reservoir. At last, we concluded that:(l) In the region of interest, there were the turbid water continental shelf facies and clear water continental shelf (carbonate platform)facies developed alternately in the Feixianguan Formation formation in Early Triassic. The former mainly developed in the second and fourth series, while the latter developed in the first and third series of the Feixianguan Formation. There were the turbid water continental shelf facies developed in the first, second and third series in west part of the region of interest. The the turbid water continental shelf facies mainly included semirestricted sea subfacies and three microfacies; The clear water continental shelf facies included four subfacies: shallows, interbank, tide flat and inner margin slope and ten microfacies. (2) The oolitic beach was the most important microfacies in the shallows subfacies, it developed at the top or upper part of two shoaling upward cycle in the first and third series of the Feixianguan Formation. The oolitic beach in the third series only developed in the eastern part of the region of interest, while the oolitic beach in the first series developed in whole area, but the best in west part. The tide flat subfacies at the upper part and top of the first series mainly developed algal mound, rod shaped algal stromatolite, undulate algal stromatolite microfacies and so on. There were the lower slope microfacies developed in Beifeng well zone in the eastern part of the region of interest. (3) The main lithogeny of Feixianguan Formation consisted of compaction, cementation, denudation and packing action. The cementation and denudation happened three times. All three times'cementations were destructive. The second time denudation was the most beneficiallithogeny. It happened during deep bury--fold return period, selectively denudated thenucleo of the ooid, formated the casting pore and made it effective accumulating space. (4) The movement of Longmen mountain island chain, Kangdian ancient land westward and the Huaying mountain fracture belt eastward was an important factor that controlled sedimentation, lithogeny and formation, distribution of the reservoir in this area. (5) The relationship between the evolution of oil-gas and the formation of pore was "Lack in the early stage, retrieve in the later stage." There were not enough oil-gas in the primary pore, while secondary pore formed a complete system with oil-gas, made oil-gas came in easily and...