The Analysis Of Sequence Stratigraphy In ShaHeJie Formation KongNan Aera Of HuangHua Basin

The south of KongNian Area is located the south of HuangHua Depression , is north from NanDi south to DengMingSi, CangDong fault to the west as the boundaries XuXi fault to the east as the boundaries,its area is 4700km2.It includes seven the second structural unit which are two big depressions which are CangDong and NanPi-XuXi depression,JieDi-QiLiDian secondary bump,SheNvSi slope,DengMingSi-WuMaYing slope,KongDian bump,and XiaoGuanTun secondary bump.The south of KongDian Area ShaHeJie Group layer after structure,its original lake basin construction changed a lot.So the structure affected the deposition.The lake basin deposition is so indistinct that it is possiable to make some huge blindness during exploring.This article's substance is to resume ShaHeJie's the lake basin sequence development mode.To analysis ShaHeJie's the lake basin sequence development mode, the first,we have to establish isochronal layer framework. According the foundation of sequence stratigraphy, interpreting the earthquake well tie section, comparing the basal level cycle, the ShaHeJie can be divided three tertiary sequences,eight tchetvertyi sequences,nine systems,nine basal level middle period cycles and sixteen half cycles.And the Sequence One is the Sha Three, the Sequence Two is the Sha Two, the Sequence Three is the Sha One.Under the inhibition of isochronal layer framework, analysis the palaeoenvironment of ShaHeJie's three sequances.The first,with analysising the lithofacies, lithofacies group type and electrofacies,we can know the ShaHeJie grows three sedimentary facies which are braid river delta, fan delta and lake,including seven subfacies and fifteen microfacies.The second ,with analysising the material source with light mineral and heavy mineral,we can know:the south WuMaYing area grows the braid river delta along the basin axial direction,SeNuSi,CangZou and NanDi near the CangDong faultage grow fan delta,WangGuanTun near the XuXi faultage grows fan delta.The last one,make the layer changing,the sandstone thickness changing and the sediment charge changing together,we can clearly recognize flat feature of ShaHeJie sedimentary facies.With the foundation of isochronal layer framework, confirming the sedimentary facies distribution,and interpreting the earthquake well tie section,we can analysis the ShaHeJie basic structure morphotype and filling pattern. It is concluded that two basic structure morphotypes and filling patterns which are duplex fault duplex filling and duplex fault single filling. Sedimentary deposit particles are thiner from sedimentation center of amphi boundary fault to upwarping of basin inner.The next ,to confirm the key point of the lake basin structure focuses the two factors:the moving period of CangDong ,XuXi faults and the formation period of KongDian structural belt.With anaylsising layer filling model and boundary sedimentary facies ,we can know that the CangDong fault,XuXi fault are border fault which deposites and controles the basin in the same time,KongDian structural belt forms in the same time when the ShaHeJie deposites.It is concluded that the ShaHeJie basin is continental facies syndeposit fault basin in the context of HuangHua depression.Based on the structure movement of the east of china tertiary,we know that this kind of the basin is formed under the action of the right hand rotation drawing tectonic stress. Based on the above views,we can clearly recognize ShaHeJie period's structure and deposition.We can anaylsis the possiable hydrocarbon accumulation type.There are three hydrocarbon accumulation types in the ShaHeJie period:structure-stratigraphic hydrocarbon reservoir,lithologic updip pinchout hydrocarbon reservoir and layer upfold hydrocarbon reservoir.This conclusion is important significance to exploration activity of KongNan area ShaHeJie.