A Study on the Genesis and Evaluation of Tight Sand Reservoir in Daniudi Gasfield
|School||China University of Petroleum|
|Keywords||Ordos Basin Daniudi gas field Diagenesis Controlling factors Reservoir Evaluation|
The Ordos Basin Daniudi gas field development characteristics of the reservoir lack of understanding of the system . Papers to the modern theory of sedimentology and reservoir geology theory as a guide , the integrated use of the core , logging , logging , production testing and analysis laboratory , Carboniferous - Permian reservoir characteristics and effective reservoir control factors and reservoir evaluation , a comprehensive and systematic study . The work area deposition Background braided river delta sedimentary microfacies of braided river delta plain and braided river delta front deposition . The study suggests that reservoir types of clastic rocks , including conglomerate , conglomerate and sandstone , showed a higher element of maturity and lower structural maturity . Reservoir diagenetic stage can be divided into early diagenetic stage B , the middle diagenetic A1 , the subperiod A2 and diagenetic B period , mainly developed compaction , cementation and metasomatism authigenic clay mineral cementation , dissolution and other diagenetic events . The reservoir space by cause divided into primary porosity , secondary porosity and cracks , which mainly secondary porosity . With increasing depth , reduced primary porosity , secondary porosity and cracks , vertical on the major development of two secondary pore zone . The one hand , the micro- cracks in the sandstone pore connectivity , sandstone reservoir performance , on the other hand acts as the output of fluid migration catheter . Carboniferous - Permian reservoir pore structure in the holes - micro throat , is a low permeability reservoir . Macro of reservoir properties controlled by tectonism ; vertical , mainly influenced by diagenesis ; plane , mainly influenced by deposition . Compaction and the denser matrix contents reservoir rock , reservoir quality is poor , on the contrary , good reservoir properties . The the reservoir evaluation classification criteria and study area reservoirs whole divided into four categories on the basis of the main controlling factors of reservoir properties Ⅰ and Class Ⅱ reservoirs effective reservoir . The results show that the favorable reservoir more than concentrated in the central and southwest areas of the work area , depositional environment braided river delta front , the main types of sand bodies underwater distributary channel sand body , rock type multi- to coarse-grained to grain quartz sandstone , lithic quartz sandstone .