3D Geological Model Study Of WT Gas Field In The S Block Of East Java Basin, Indonesia

The WT gas field is located in the East Java Sea in Indonesia,7km away from the west of O Oilfield,and its water depth is 200 m.It is a lithological-structural gas reservoir as a whole,and the target layer is the Neogene Pliocene Selorejo and Mundu.The lithology is globigerina grainstone,globigerina wacke/packstone and globigerina pack/grainstone.The WT gas field is still in the development preparation stage at the moment.In order to calculate geological reserves,deploy a reasonable development plan,and conduct economic evaluation,it is necessary to make a fine description of the WT gas reservoir and establish a reservoir geological model.This paper systematically describes the stratigraphic development and tectonic evolution in the East Java Basin and the gas field,the relationship between sedimentation and tectonic evolution in the basin was analyzed.The lithology,pore structure,and pressure characteristics of the reservoir were analyzed using data from wells,cores,cast thin sections,testing,logging and seismic data.By the study of reservoir "four-character" relationship,a reservoir parameter logging interpretation model was established and the thresholds of reservoir parameters was determined.The thresholds of effective porosity and water saturation of the reservoir is 17%and 60%,the thresholds of resistivity is 5?·m.According to the reservoir testing and logging interpretation results,4,21 and 38 gas-bearing intervals were discovered respectively from wells WT-1,WT-3ST1 and WT-4.Based on the fault model,the seismic interpretation surface and the well tops data,the structural model is built by using the Kriging interpolation.According to the shale volume curve and porosity curve,the lithofacies of the single well was divided,and the distribution of the lithofacies in the three dimensional space was simulated by the sequential indication simulation method.Using the sequential Gaussian simulated method and lithofacies control technique is to simulate porosity model.Taking the reservoir as control condition and lithofacies model as the constraint,combining with gas-water distribution,using the sequential Gaussian simulation method to build the saturation model comprehensively.Based on core analysis and acquiring the relationship between porosity and permeability to get permeability model by property calculator.Based on the above research results,Reserve calculation,perforation interval analysis and well location analysis are completed,which can provide guidance for the gas field development plan in the study area.