Geological Model Of D66Area Daniudi Gas Field In Ordos Basin

Daniudi Gas Field is a very important gas field of Northern China Branch ofSinopec, locating at the east part of Yishan Slope in northern Ordos basin of Chinaand spreading across Yulin City of Shanxi Province and Ordos city of InnerMongolia Autonomous Region. Daniudi Gas Field has great proven geologicalreserve, which is454.563billion m3by the end of2012.Its structure is simple, withlow porosity, low permeability, low pressure, low yield, strong heterogeneity and nobound or bottom water and tapped by lithology. These geological characteristicsmake the development so difficult that it becomes a world-class challenge.By analysing the logging data, core data and preliminary research results of D66well area of Daniudi gas field in Ordos Basin, small layers division and correlation,sedimentary microfacies description and sand distribution figures were accomplished.Three-dimensional geological model was also done with sand distribution figures asconstraint and the integration of deterministic modeling and stochastic modelingmethods. The key findings are:1. According to the principles and ideas of small layers division and correlation,7mark layers were selected from target formations, typical gas wells generalstratigraphic column and10inter-well constrasting profiles were established, smalllayers division and correlation were accomplished. The target formations of D66well area are divided into7groups and14small layers.2. After the comprehensive analysis of geological sedimentary background, coredata and well logging data of Daniudi Gas Field, H3of P2x formation is believed tobe meandering river sedimentary environment, which point bar and riverbedretention sedimentary microfacies are relatively more developed. H2and H1arebraided river sedimentary environment, which channel bar and riverbed retentionsedimentary microfacies are relatively more developed. Shanxi group is delta plainsedimentary environment, which distributary channel and marsh microfacies arerelatively more developed. Taiyuan group is coastal sedimentary facies with sandbars, which barrier islands and tidal flat sedimentary facies are relatively moredeveloped. 3. Combining previous research results, the D66well area in all gas well data ofsand body, were mapped7big layers14small layers distribution maps. From eachlayer sand distribution maps shows the entire D66well area basic for north and southdirection of sand body distribution, including D66well area H1and T2sand body isthe most development, local sand body thickness up to40meters.4. This model uses deterministic modeling for lithology model and stochasticmodeling for property model, which is a collaborative and multi-informationapproach to build3-D geological model for D66well area. Lithology model isconstrained by sand distribution maps, thus modeled with sequential Gaussiansimulation method facies controled stochastic modeling. Many models were built tochoose one which can best present the subsurface property distribution of D66wellarea.