A New Methodology on Reservoir Modeling in the Fracture-Cavity Carbonate Rock of Tahe Oilfield

摘要

Tahe, one of the largest scale oilfields which are discovered inrnwestern China recently, in which Ordovician carbonate as thernmain storage, characterized with deeply embedding andrnvarious storage type, mainly are cavities and fractures. It isrndifficult to describe as its serious heterogeneity and there isrnrare technical reference regarding the reservoir modelingrnmethodology.rnCommonly, the geology modeling is based on well loggingrnand seismic data, and the stochastic method is reasonablernapplied. However, Tahe oilfield has very limited seismic datarnand poor well logging interpretations, especially for thernfracture-cavern section. Furthermore, as it is controlled byrnpaleukarst, the stochastic geological method, which is widelyrnused in the ordinary sedimentary, is unacceptable to Tahe. Thernvolumetric reserves calculation, which is suitable to sandstonernbut is not applicable to the fracture-cavity reservoir either, as itrncan not be proved in the severe anisotropy fracture-cavityrncarbonate formation. Furthermore, the concept of porosity andrnsaturation is less meaningful in this kind of reserves. As arnresult, there is no applicable modeling method to describe therngeological characters of the Tahe carbonate reservoir.rnA new methodology which is characterized by the fracturecavityrnvolume is presented in this paper. Accordingly, a newrnreservoir modeling and a new reserve calculation is built up.rnMainly from geology, combined with static and dynamic data,rna quantified 3-D reservoir model of Ordovician reservoir isrnformed, and this modeling methodology is proved practicallyrnby the results of history match from the streamline numericalrnsimulation. The result will technically support the exploitationrnof Tahe oilfield.