Study On The Sedimentary Facies Of Enping Formation In Wenchang A Depression

Based on the comprehensive analysis of lithology，well logging curve，traceelements and seismic reflection characteristics，in combination with the regionaltectonic background，analyzed Enping Formation ‘s sedimentary environment ofWenchang Asag in Pearl River Mouth Basin and its surrounding areas，discussed therelationship between distribution of sedimentary facies and characteristics ofhydrocarbon source rock.Based on the study of logging facies，seismic facies and other facies marks，identified four sedimentary facies types of Enping Formation about research area suchas shore-shallow lacustrine facies，semideep lacustrine facies，fan delta front faciesand braided river delta front facies and so on，summarized the characteristics ofsedimentary facies. The trace element analysis test shows sedimentary period’sclimate was damp，water depth became shallow gradually as a whole on the trend.During Enping Formation sedimentary period，the study area presented（braided river,fan）delta and semideep lacustrine，shore-shallow lacustrine symbiotic sedimentaryframework.The evolution of sedimentary facies is mainly controlled by the structuralfactor，established Enping Formation of Wenchang Asag lacustrine-delta sedimentarymodel. The organic matter abundance，organic matter type of dark mudstone is closelyrelated to sedimentary environment.Ⅰ type organic matter develop in shallow andsemideep lacustrine facies. Dark mudstone of shore lacustrine，fan delta front andbraided river delta front facies contain high plant component in organic matter and itsorganic matter’s abundance is relatively higher.