Research On The Sedimentary Characteristics Of Chang 6 Oil-bearing Formation In Heshui Area Of Ordos Basin

Heshui Area is located in the southwest of Ordos Basin.Chang 6 Oil-bearing Formation is one of the main production floors.Existing drilling data shows that the oil-water relationship is complex in the area.So,we should research the sedimentary system type,microphase characteristics and their evolution of Chang 6 oil-bearing formation.The paper has acquired following results:1.Applying the frontier methods of sedimentology,stratigraphy,selecting a lot of core logging and logging data,carrying out the stratigraphic division and correlation,the Chang 6 oil-bearing formation in Heshui Area is divided into three oil layers,respectively,for the Chang 61 oil layer?Chang 62 oil layer?Chang 63 oil layer.2.Based on the analysis of the petrological characteristics,formation thickness,logging facies,single-well facies,cross-sectional facies and sandstone thickness,combined with previous human advanced research results,the sedimentary system type and microphase characteristics of Chang 6 oil-bearing formation in Heshui Area was studied.The source of the study area is diverse during the depositional period of Chang 6 oil-bearing formation.The main source is southeast-northwest and southwest-northeast.There are six sedimentary subfacies developed in Chang 6 oil-bearing formation,are respectively braided river delta front,shore shallow lake,half lake-deep lake,the inner fan of lake fan,the middle fan of lake fan,the outer fan of lake fan.The braided river delta frontier is further divided into underwater distributary channel,underwater diversion bay,estuary dam.What's more,the inner fan of lake fan is further divided into the main channel and the main channel outside.Besides,the middle fan of the lake fan is further divided into braided channel and braided channel outside.3.Above all,from bottom to top,the Chang 6 oil-bearing formation shows the plot of the sedimentary sequence,which reveals the distribution characteristics and evolution of the Chang 6 oil-bearing formation.In the Chang 6 oil-bearing formation of the Heshui Area,there are four factors which integrated controlling deposition,including structure,palaeogeomorphology,palaeoclimate and sediment supply.