Sedimentary Characteristics And Comprehensive Evaluation Of MO Formation Reservoir In C Oilfield Of Peru Ⅵ Area In Tarala Basin

The Talala Basin is located on the continental shelf of the northern coast of Peru.The structure of the basin is between the subduction zone of the Pacific plate toward the South American continental plate and the volcanic arc The study area is located in the south central part of tarala basin,which is a typical fault block reservoir.At present,there are still some problems,such as structure and fault system,reservoir sedimentary characteristics,sand body superposition law,which affect the further development of the oilfield.On the basis of previous research results,this paper makes full use of logging and logging data,overcomes the shortcomings of lack of core and seismic data,establishes standard wells to carry out fine research and characterization of structural fracture system and sedimentary microfacies in the study area,clarifies the characteristics of fault development and the plane distribution law of sand body,clarifies the spatial distribution pattern of sedimentary microfacies and the physical properties and heterogeneity of reservoir Qualitative research.Combined with the characteristics of sedimentation,structure and reservoir development,the reservoir is comprehensively evaluated and scored to implement the distribution law of high-quality reservoir.The main achievements and conclusions are as follows:1.Based on the original stratigraphic scheme and structural interpretation results,through regional stratigraphic correlation,the division results of sup layer,Med layer and inf layer of Mo formation are determined,and the structural characteristics of sup layer and inf layer are re implemented.The Mo formation in the study area shows the structural characteristics of two "fault nose" bulges and two "groove" depressions.It mainly develops high angle normal faults and thrust faults developed in the Middle East,resulting in some stratigraphic repetition.2.Using residual thickness method to restore the paleogeomorphological features of the study area,the northeast of the study area is a raised area,the southwest is a depression area,and the terrain slope also presents the shape of northeast steep and southwest gentle.The provenance of C oilfield mainly comes from the raised area in the northeast and the amotapes mountain in the northeast.3.Combined with logging lithology,the lithologic classification and division template of the study area is established,and the lithology of the study area is divided into mudstone,medium fine sandstone,coarse sandstone and sandy conglomerate.The study area mainly develops fan delta front deposits under the background of semi shallow sea shallow sea sedimentary environment.According to the well logging facies template,sedimentary parameters and Log map,the internal sedimentary microfacies are subdivided,mainly including underwater distributary channel,mouth bar,underwater distributary Bay and sheet sand sedimentary microfacies.4.Based on the physical property interpretation model of Mo formation in Peruvian 10 area,the logging interpretation standard of reservoir porosity and permeability parameters is established,the plane distribution map of porosity and permeability of sup and inf formation of Mo formation is drawn,and the penetration coefficient and variation coefficient of reservoir permeability are calculated.As a whole,Mo formation is a low porosity,low permeability and heterogeneous reservoir.5.Using the method of grey correlation and AHP to calculate the weight,the evaluation system is established to evaluate the reservoir comprehensively.According to the scoring results,the underwater distributary channel in the middle of the study area and Hekou dam in the southwest are class I reservoirs,with sufficient material supply,well-developed sand bodies and high reservoir physical properties;the underwater distributary channel in the northeast and southwest of the study area is class II reservoirs,with general sand bodies and good reservoir physical properties;the underwater distributary Bay and fan delta lobe in the Middle East and north of the study area The sheet sand in the outer edge is a type III reservoir,with poor development of sand body and low reservoir physical properties.