Study On The 3D Geologic Modeling Of Chang6₁ Reservoir In Majiashan-Baoziwan Field

Ordos Basin is the second largest sedimentary basin in China. And it is one of the primarily discovered and developed basins which is a large petroleum-bearing basins. The reservoir of Yanchang formation of Upper Triassic in Ordos Basin is well known as low porosity, low permeability, and extra-low permeability. In recent years, during the development of low permeability reservoir, there are many high quality reservoir been discovered. This study takes modern sedimentation theory and sequence stratigraphy as the guidance, integrates data consisting of core, outcrop, well logging and analysis assay to fine describe the physical property and heterogeneity characteristic of low porosity reservoir. The 3D geological model ,which provide the basis for adjustment of development plan, was built with phase-controlled stochastic modeling method.This paper takes Chang61 reservoir of Majiashan-Baoziwan well field as study object, and determine the sedimentary facies type of this region been the front-delta deposition according to elaborate observation of core and outcrop. The sequence-stratigraphy framework was been built by depositional cycles comparison, lithofacies thickness method and marker bed control. The sedimentary distribution and evolution law of the sequence-stratigraphy framework are revealed through the analysis of core facies and well logging facies.With study about four-relationship, taking test oil result and geological parameter from core data as the basis to build logging interpretation model which under control of geological condition, and evaluation criteria of hydrocarbon and water, the lower limit standard of effective pay thickness. With these study above, we provide integrated interpretation and multi-well evaluation for 47 wells in this region, and provide detailed study for Chang61 reservoir's microscopic characteristic with multiple analysis for the assay data. The result shows that the pore structure of this reservoir is mainly consisting of fine pore and minute throats. The reservoir get serious heterogeneity characteristic in layer, so the heterogeneity characteristic and interbed distribution are mainly under control of sedimentary micro-facies and base level cycle.For this situation, we should choose representational packing coefficient, formation coefficient and flow zone index as basis to divide the reservoir into three types. The reservoir with higher quality distribute on underwater distributary channel of main facies and main production layer of study area with better physical properties and connectivity.Based on comprehensive geological study, with analyzing and selecting for multiple modeling methods, adopt sequential indicator stochastic simulation to build structure model, micro-facies model and phase-controlled attribute model on the basis of sequence stratigraphic framework. The complete 3D geological model is built finally, and it could provide geological basis for development plan and adjustment plan of oil field...