Analysis Of Sedimentary Facies And Characteristics Of Gas Reservoir In CiYing Formation In Luliang Basin

Luliang basin is located in Dianong depression fold belt in the west rim of theYangtze plate. Juncture of kang dian block, belonging to qujing fold belt of Diandongfold belt of Yangtze paraplatform. As a Cenozoic basin，which has the mono-faultedstructural characteristics, that is west-faulting and east-overlapping, maximumsedimentary thickness is about2000m, base of the basin is for the devonian orPermian. Main boundary faults in the east of Luliang Basin have been developingsince the yanshan period, which control the formation and structural evolution of thebasin.Basis for Nonmarine sequence stratigraphy and high resolution sequencestratigraphy analysis method, isochronal stratigraphic units frame has been built up,.In this paper, Ciying formation have been divided into5third grade sequences-SQ1-SQ5.In general, sedimentary pattern conforms to typical basin sedimentary model inwhich Fan delta sediments developed well in the steep slope; delta-lacustrine faciesin gentle slope, deep lake-half deep lake facies in the central area.North and west of the basin mainly shows delta depositional system, the eaststeep slope zone developed fan delta depositional system, in southeast zone existsunderwater fan, which is a good reservoir sand body for gas and oil.Combination drilling information, mud logging, high resolution seismic data andsedimentology characteristic analysis, based on single phase analysis,crosswellsections and seismic attributes (facies) analysis, main depositional system types--thedelta, fan delta, lakes and underwater fan have been established. Meanwhile, reservoirsand body in favorable structural area was researched in sedimentary subfacies andmicrofacies, the results revealed that delta underwater branch flow channel, mouth barand delta front sheet sand in west and north slope belt; fan delta front sheet sand,underwater distributary channel and local turbidite sand in the east steep slope belt arefavorable gas reservoirs in Luliang basinLogging curves comprehensive analysis shows the main production layers are inCiying formation. Characteristics of gas bearing logging curves illuminate that thenatural gamma ray has low value, natural potential displays obviously negativeamplitude, resistivity curve value shows higher value, acoustic time is significantlyhigher, density curve value becomes low. In the above work, on the basis of theextraction of seismic attributes such as amplitude, frequency and phase in favorablelayers, the relationship between gas and seismic attributes is identified and modelcognition has been established.