Changxing Formation In Northeastern Sichuan YB Region Reefs Characterization Reservoir Prediction

Carbonate is calcium carbonate as the main ingredient of chemical sedimentary rocks,some of which is consisted of biological skeletal or clastic deposition. Carbonate reefreservoir is mainly made of a special build by the biological carbonate constructs,which is the natural ideal place where gas and oil reserve. It is the main type of oil andgas deposits in carbonate sediments, and has a vast potential for oil and gasprospecting. The main reservoirs of marine carbonate contain rocks reefs, beaches andinsider dolomite. According to existing research results and drilling data，the marinecarbonate reservoirs of the Sichuan Basin in northeast YB region is main reefreservoir.With the gradual increase in the complexity of the marine oil and gas explorationand mature of seismic interpretation, seismic oil and gas forecasting techniques arealso gradually refined and accurate. To improve the accuracy of reservoir prediction, itis a particularly important step to depict the reefs in the plane distribution and spacedistribution and its planar distribution and spatial distribution will directly affect theoil and gas exploration results. The article first analyzes the oil and gas geologicalconditions of source, reservoir and cover to grasp marine strata in the vertical mutualdevelopment to form a good configuration relationship on marcoscopical in YBregion. And then through to explain and track the purpose layer, it obtains thestructural map and structural characteristics of the study area and analyzes itsstructural characteristics and the implement the structural form. Then the paperexpands Changxing Formation Ш sequence stratigraphy. It utilizes facies analysisdata of individual wells drilling to study seismic facies of target layers in the wholeregion and transform seismic facies into sedimentary facies according to single wellsfacies characteristics. With seismic attributes extraction and analysis, the article gainsthe reefs in the plane distribution and reservoir boundariesaccording to instantaneousampltitude anomaly. Finally, it obtains the spatial distribution feature of reef reservoirthrough the constrained sparse spike inversion.The main research content and key results are as follows:1. This paper studies the geological conditions and the vertical configurationcharacteristics of source, reservoir and cover in YB region，which lays the foundation to describe the back of reef portray and reservoir prediction.2. The paper analyzes the structural characteristics of the YB area, with nearlyeast-west two-Long clip a concave flat tectonic belt. Due to Small tectonic movement,the fracture is not developed, which is an important condition of the reef reservoirshape preserved intact.3. The article expands Changxing Formation Ш sequence stratigraphy. It utilizesfacies analysis data of individual wells drilling to study seismic facies of target layersin the whole region and transform seismic facies into sedimentary facies according tosingle wells facies characteristics, and meanwhile analyzes depositional environmentto control reservoir as well as favorable reservoir area.4. Based on drilling and outcrop data and seismic response characteristics, itframes recognition mode of reef reservoirs. In other words, under the constraints ofsedimentary facies conditions, it uses reef on the seismic profile reflectioncharacteristics to expand the seismic facies classification. It utilizes seismic attributeanalysis and acoustic impedance inversion to determine the boundary of the reservoirunits and depict the distribution characteristics of the reservoir space.