Carbonate Reservoir Prediction Technology And Its Application In Kekeya Area

Kekeya condensate gas filed located in the southern of Yecheng depression, the western of the second row of the Kunlun tectonic belt. The structure of Kalatar formation is relatively simple. It is an anticline with short axis, east-west orientation. And the reservoir is mainly fractured-porous type, with deep buried and strong heterogeneity. Previous prediction of the reservoir was still based on post-stack inversion and conventional seismic attributes, so the prediction accuracy is low. And the study of fractures was mainly from the outcrop, core and logging, and from analogy of lithology or structural parts for fracture prediction. The inefficient production of well KS103 shows that the carbonate reservoir exploration is very complicated. So, the prediction method is the bottlenecks which limited the exploration and development of the carbonate condensate reservoir in this area.This study carried out reservoir and fracture prediction target at the Plaeogene Kalatar formation. Base on accurate interpretation of the structure , this study has predicted the fractured reservoir by advanced reservoir characterization methods, detailed analysis the controlling factors of the reservoir , and combined with fluid detection technology, re-evaluated the oil and gas reservoirs in this area.During the study of the Carbonate reservoir prediction and characterization of Kalatar formation, for the high depth and fracture-porous developed characteristics ,in order to improve the reservoir prediction accuracy and fully tap the seismic information, a series of geophysical reservoir prediction methods has been used, such as the spectral imaging technology, well constrained impedance inversion, EI inversion, and azimuthal anisotropy fracture prediction technology. By selecting the efficient seismic attributes from all of the extracted, this study indicated that the post-stack impedance and pre-stack EI inversion can well descript the reservoir and fluid properties. The post-stack impedance inversion can describe the reservoir on horizontal and vertical distribution, and meet the deposit principle. The Poisson’s ratio obtained by EI inversion can describe the distribution of oil and gas.