Recognition,Distribution Prediction Of Lime Mudstone Of The Lower Es3 In Shengtuo Area Of Dongying Depression

Shahejie Formation's Third and Fourth Member of Shengtuo Area has a large number of nearshore subaqueous fan and deep water turbidite fan deposit.The structure of Shengtuo is complex,the numbers of oil-bearing layers and the types of reservoirs are numerous.With the further exploration,the lithologic reservoirs that the onturbidite sand body has become the research focus.During the deposition of the turbidite sand body,a large number of lime mudstone has developed in Shengtuo Area,the geophysical response characteristics of the gravel body and lime mudstone are similar,and these similar characteristics caused difficulties in the exploration of lithologic reservoirs at present.The paper took the the Lower Es3 in Shengtuo area of Dongying depression for research objects,combined with the core,logging,seismic,geochemical and other information,classified the fine-grained sediments such as lime mudstone and the geophysical response characteristics of the lime mudstone,recognized and predicted the distribution of the lime mudstone in Shengtuo Area.The main understandings are the following:The fine sediments of the work area can be divided into five lithofacies: carbonate rock,mudstone,lime-sandy mudstone,mid-calcium-containing lime mudstone,high-calciumcontaining mudstone,and the lime mudstone mostly is lamellar.Because of the abundant source of the lower part of the Third Member of the Shahejie Formation,the geochemical elements of the lime mudstone are characterized by deep water deposition,the core and slice observation found that the lime mudstone contains amount of sand.Mid-calcium-containing lime mudstone,high-calcium-containing mudstone,mudstone could be divided by the two-dimension cross-plots of the gamma ray logs,acoustic logs,resistivity logs and compensated neutron logs,and limemudstone that contains sandstone and sandstone could be divided by three-dimensional cross-plots by these logs.High-calciumcontaining mudstone has low gamma value,mid-acoustic travel time and mid-compensated neutron,mid-calcium-containing lime mudstone has mid-gamma value,mid-high acoustic travel time,low-mid-resistivity and mid-high compensated neutron,mudstone has high gamma value,long acoustic travel time,low resistivity and high compensated neutron,sand has lowmid-gamma value,low acoustic travel time,mid-high resistivity and low compensated neutron,Lime mudstone that contains sandstone has mid-gamma value,low-mid-acoustic travel time,mid-resistivity and low compensated neutron.In the system tract scale,the lithologic association can be dividied into seven types,the Sandstone-mudstone interbedding,mudstone alternated with lime mudstone,mudstone alternated with sandstone,lime mudstone alternated with mudstone,lime mudstone alternated with sand,sandstone alternated with lime mudstone,Lime-mudstone-mudstone interbedding.The seismic response characteristics of different lithologic association types are different.When the lime mudstone alternated with mudstone and mudstone alternated with lime mudstone type developed the thick-bedded lime mudstone,the seismic response of them were mainly characterized by low frequency and low amplitude.Lime mudstone mainly distributed in highstand and transgressive in vertical,and mainly distributedin the edge of the fan and the central part of the lake basin in the plane.