Simulation of Lithology and Porosity of Volcanic Rock Reservoir Based on Sequential Indicator Simulation

Because of the complexity of the composition and structure of volcanic rocks,it is difficult for lithology identification,reservoir parameters calculation and spatial distribution description.Taking the volcanic rocks in the top of Yingcheng Formation,Changling sag,for studying object,by means of the sequential indicator simulation,and making use of the lithology identification and porosity calculation in each single well,as well as selection of various parameters of variogram,the 3D simulation about the distribution of lithology and porosity in the study area was carried out.Both of the tuff and rhyolite were developed in this area,and as for rhyolite,both of the porosity and its variation coefficients are smaller;in other hand,as for the tuff,both of them were much bigger.The simulation results showed that the porosity and its variation coefficient are associated with the structural location.While the volcanic rock locate at uplift and hollow zone,the porosity will lower than the volcanic rock locate at ramp region,but its variation coefficient will be higher.