Log Geological Model In The Upper Of Xiaganchaigou Formation In MB12Northern Margin Of Qaidam Basin

The exploitation in the upper of Xiaganchaigou formation in MB12oilfield has achieved many new accomplishments, which open out a promising trend in north of the Qaidam Basin. It is important to explore the high-efficiency technique and policy in the upper of Xiaganchaigou formation reservoir, because it might be a new pre-production and exploitation oil layer. MB12wellblock, which is the main trial part in north of the Qaidam Basin oilfield.Based on information collection, field core observation combined with a variety of core analysis and testing methods to study the stratigraphy, structure, sedimentary, reservoir and other basic geological characteristics in the upper of Xiaganchaigou formation reservoir in MB12wellblock, the study comprehensively apply multi-disciplinary theories and methods. The geological model for three-dimensional visualization in the upper of Xiaganchaigou formation reservoir in MB12wellblock, which established by the PETREL software, provides geological model and the theoretical basis for the probe of exploitation technique and policy.Researches show that:1)In the upper of Xiaganchaigou formation reservoir is a general slowing western-leaning monoclinal structure, anomalous nose structures are developed in the middle of the MB12wellblock;2) Combined with the regional geological setting, using the analysis of lithofacies, two kinds of micro sedimentary facies are distinguished,including the sandstone of underwater distributaries channe, and interdistributary bay.3) To lithology is mainly brown mudstone, argillaceous siltstone, silty mudstone and grey, tan siltstone and fine sandstone in the upper of Xiaganchaigou formation reservoir in MB12wellblock; Sandstone have low compositional maturity and structural maturity; The most of quartz in detrital composition content, and the feldspar second;4) The reservoir porosity between15%to20%in the upper of Xiaganchaigou formation reservoir in research area, and20%on average; The primary pores disappear, so pore types mainly on secondary porosity and the expulsion pressure is low; Permeability change range is larger, in100-300md, permeability is good, for the hole in the permeability of reservoir.On the basic geological characteristics in the upper of Xiaganchaigou formation reservoir in MB12wellblock, three-dimensional geological model in the upper of Xiaganchaigou formation reservoir is established using the PETREL software, including the well model, structural model, facies model and properties model, such as porosity model, permeability model. The model highly display the sand body of the reservoir and characteristics of the properties, at the same time provide the data volume for subsequent simulation and lay the foundation for further exploitation.