Sedimentary Facies And Reservoir Distribution Of The Changxing Formation In The Longshanchang-Tieshan Block, Northeast Sichuan

Longhuichang-Tieshan district is located in the west of "Kaijiang-Liangping Trough",northeastern Sichuan Basin.In this region,it is reveals that there are considerable potential and promising exploration prospect in the organic reef reservoirs in upper Permian system Changxing formation.However,due to the inner complex structure and the restriction of previous 2D seismic data,it is difficult to accurately predict the distribution and extending scope of reef,which constrains the further study of reservoir distribution and attenuates the effect of gas exploratory development.Hence it is requisite and indispensable to combine the latest 3D seismic data to implement the sedimentary system and the distribution of reef reservoir in Changxing formation.Based on previous research,this paper applies theoretical study methods of Vail classic sequence stratigraphy to stratigraphy correlation,the Changxing formation is divided into three cycles.With core observation and logging data,sedimentary characteristics and spread are analyzed.Under the controlling of sequence stratigraphic framework,we also borrow some theory and method of seismic sedimentology to fulfill the study on the distribution of reef.For instance,the integration of the seismic facies,sedimentary facies,seismic attributes optimization and analysis,stratal slicing technique.Moreover,the reservoir characteristics and distribution are clarified.And for better effectiveness of reservoir evaluation in the study district,a new reservoir evaluation standard has been built by using cluster analysis.Finally,the integrated geological and geophysical analysis on sedimentology,reservoir comprehensive evaluation and distribution of dolomitized reservoirs,they all conduct to forecast and elucidate the distribution of favorable reservoirs.In a word,deepening the study on sedimentology of reef reservoir and ascertaining the distribution scope and scale,as well as looking for the range of favorable reservoir,would be of great significance for the next exploration target selection and well deployment.