Fractured Reservoir Characterization And Fracture Distribution Prediction In Hubuzai Gas Area

The Fractured reservoirs are typical oil reservoirs with low porosity,low permeability and serious heterogeneity.The distribution of fracture system is impacted by structural evolution,lithic facies,lithology and other factors.Fracture of low permeability and compact reservoir can influence the distribution of oil-gas reservoir,act as the main flow channel of oil and gas as well as the controlling factor of the level of oil or gas well productivity.The reservoir rock of the fourth member of the Shahejie formation in Hubuzai,Dongpu depression is compacted low-permeability tight sandstone layer with poor petrophysical property,which is defined low permeability fractured dual-pore medium reservoirs.Influenced by the fracture and reservoir development,different parts of gas well can vary considerably;reservoir types can make development of gas reservoirs and distribution of residual gas quite differently.Therefore,the prediction of fractured reservoirs is a key to improve exploration and development of oil-gas reservoir in Hubuzai.At the beginning of the study,the author analyzed the geological factors that impact the cause,phrase and controlling of fracture through comprehensively observing its geologic feature as well as gave a qualitative description for genetic mechanism of fracture system.Then by combining conventional logging data with imaging logging data.the study presented the characteristics of logging response to fracture.At last,the author applied to the 3-D seismic data of Hubuzai area collected in 2009 and other reservoir prediction methods such as tectonic curvature,coherent properties and automatic ant tracer and concluded the study a precise prediction of planar distribution of the fractures.Finally.the the comprehensive consideration of geological environments has been made to predict the macro fracture-developed zone of fracture distribution.Though the method is different,the results which reflected the distribution law are coupled to some extent.The studies above indicated that post-stack coherence technique played an effective role in predicting the distribution of huge faults and large fracture zone while ant tracking technique is better at tracking the vertically distributed ones.Though the resolution ratio of a normal curvature attribute is higher than that of post-stack coherence technique and ant tracking technique,the result is hardly satisfiable.The study showed that fractures in Hubuzai area are predicted to be developed in NE direction,nearly N-S trending distribution.There develop three nearly N-S trending fault zones in the northwest of the study region.The gas reservoir development zone is mainly located in N-E fault zone.The entire Shahejie fractures has inherited from bottom to top,there's no big differences in the fractures' distribution,scale and the direction.The predicting outcomes were consistent with the actual drill condition,which proved the validity of seismic reservoir prediction and its application in fracture detection.