Research On The Median Deep Reservoir Characteristics In Shahejie Formation Of Raoyang Sag's Troughs

Raoyang Sag is the most abundant sag of oil and gas in Jizhong depression,at the same time,it is the one that has the best exploration result in Huabei Oilfield.As the Theory of hydrocarbon accumulation in troughs becomes rich,which guides the oil finding in lower sag exploring practice,it is necessary for us to have a deep knowledge on characteristics of median deep reservoir in troughs.This paper takes the median deep reservoir of the Raoyang sag's troughs as research object,there are mainly formations located in Es2 and Es3 of Maxi, Suning, Dawang zhuang,Liuxi and Liuchu five regions. On the basis of previous research results, guided by the Discipline theory of Structural Geology,Sedimentary petrology,Petroleum Geology,Reservoir physics,Reservoir Geology and so on,and through Core Drilling,cathodeluminescence,scanning electron microscope, fluid inclusion,Carbon and oxygen isotope to observe,appraise and analyse the testing way,moreover,combined with quantities of Conventional sheet,X-ray diffraction of clay minerals,Vitrinite reflectance,The maximum peak temperature pyrolysis,Core properties,High pressure mercury,Logging Test to analyse assay report,I study the characteristics of the median deep reservoir in Shahejie Formation of Raoyang Sag's troughs,.the main achievement of this paper are as follows:(1)The median deep reservoir sandstone which locates in Es2 and Es3 of Raoyang sag's troughs has a number of Quartz and Feldspar,the main type of reservoir sandstone is Arkose,Lithic feldspathic sandstone comes second,which is the low paperal maturity and middle textural maturity.The matrix contents are low.There are many kinds of cements together with high contents and the chief components are Calcite of Carbonate minerals.(2)The median deep reservoir space type of Raoyang Sag's troughs is Porous and there are occasional cracks. Es2 is given priority to with secondary pore, and Es3 reservoir's secondary porosity develops along with primary pore.Overall for low porosity,laid low porosity,low to ultralow pore,and low permeable sublayer, Ultra-low permeability, low permeability reservoir level, on the longitudinal roughly three Anomaly zones with obvious regional differences.The regional property of Dawang Zhuang is the best on the plane;SuNing and Liuchu area comes second. Pore structure is complex, generally for the narrow pore throat, poor sorting.(3)The median deep reservoir's compaction of Raoyang Sag's troughs is strong and Carbonate minerals, Clay minerals, Siliceous cements develop commonly.Calcite cement, carbon and oxygen isotopic paper of paleosalinity's Z values tested in Laser micro area that belongs to Department of Geology University of Regina are less than 120,and the cause is fresh water,palaeogeothermal measuring is about 65 to 129.9 ?, and 102.8? is the average one,which mainly concentrated in the range from 100 to 110 ?, fluid inclusions' homogenization temperature mainly range from 100 to 140 ?, and the average one is 115?;It Showed that calcite cement formed in the A period of Diagenetic stage, which is the Late cause,Pore-filling, Pore-filling and Tight reservoir.Secondary porosity develops in high quality reservoirs development zone,and the most important one is Feldspar dissolution.Usually,primary pore also develops where the Secondary porosity develops.(4)Raoyang sag's troughs median deep reservoir sandstone which lies in Es2 and Es3 goes through the syndiagenetic stage, early diagenetic stage evolution.Totally, it has reached diagenesis stage- stage A. For A1 sub stage,there are low organic maturity,high yield of organic acids, and it is the secondary phase zone;For A2 sub stage,there are degree of organic metamorphism, Peak oil generation,and the Concentration of organic acids decreased,at the same time,cementation appears, so that Physical Properties are worse compared with the A1 sub phase,and porosity decreased from 8% to 10%, a small part of it attain the diagenetic stage B phase.(5)Raoyang sag's troughs groove of Shahejie Formation in the median deep reservoir classification evaluation standard is initially established, and makes a comprehensive evaluation of Portrait of a single well,Even lateral wells and Plane distribution characteristics. Type IV and Type III are main reservoirs, class II is less,class I is least.The high quality reservoirs are mainly developed in underwater distributary channel sand of Braided river delta front and Shore shallow lake sand bar.The reservoir level can reach the second class B.(6)The median deep reservoir's controlling factors of development in Raoyang Sag's troughs include tectonic and Factors deposition.Tectonic macro control depositional system and form crack microscopically. Reservoir properties and Quartz feldspar content positively correlated, and cuttings heteroaryl cements are negative correlation.Sedimentary microfacies control sandbodies' development and distributary channel sand, underwater distributary channel sand,Shaba point, shore shallow lake sand bar is the quality reservoir sand bodies of Raoyang sag. Compaction and cementation pore decrease obviously,abnormal high pressure resistance to compaction,hydrocarbon charging anti-cementation retention hole,dissolution pore is increased.(7)Raoyang sag's troughs with relatively the median deep reservoir quality formation mechanism are rigid quartz grains,high feldspar content Paul hole compaction,sorting rounded,few heteroaryl and relatively few cements. Early carbonate cementation has compaction and provides Late acidic dissolution with Late acidic dissolution.Hydrocarbon charging anti-cementation retention hole,abnormal high pressure compaction pressure solution security hole,feldspar meteoric leaching dissolution and organic acid dissolution have produced a large number of Secondary porosity and few Late carbonate cements.Integrating factors of deposition,reservoir properties and status of exploration,the favorable zones of Es3 reservoir were predicted.