Low - Level Tectonic Identification And Reservoir Prediction Of Grape - Gubei Jurassic In Turpan - Hami Basin

Putaogou-Pubei area is located in the west of Taibei sag in Turpan-Hami basin and first member of Qiketai formation and third member of Sanjianfang formation are benefit reservoir strata enriching oil and gas. Affected by multiphase tectonic movement, faults are well developed. Many small and medium-sized anticlines are formed under the thrusting-nappe structure background with several low amplitude structures developed during the same time. So far, large scaled anticline structure have been drilled and the majority gained industrial oil, while the prospecting degree of low amplitude structure is very low, so low amplitude structure extremely possess exploration potentials. With the improvement of exploration degree, tectonic characteristics understanding of Putaogou-Pubei area becomes deepened. Based on drilled data, exact top position of low amplitude structure has certain deviation with previous cognitive and most initial drilling location did not fall on real high spots. In addition, there still exists some low amplitude structure failed to be identified. Therefore, determining relative reasonable structural characteristics of the region and identifying low amplitude structure are in urgent need.Based on3D seismic data of Putaogou-Pubei area, accurate structural interpretation was conducted and fracture development characteristics was studied on dominant strata from Tertiary to Jurassic. After stratigraphic classification and comprehensive seismic horizon calibration, sequence stratigraphic framework and seismic geological interpretation of major target were built, ascertaining main structural feature in the study area. In order to identify low amplitude structure more accurately, forward modeling technology was utilized to study the resolution of minor fault and micro relief structure, trying to analyzing effects of different factors on recognizing low amplitude structure. Attribute fusion could guide minor fault recognition and verify the reliability of fault interpretation scheme. Incorporating velocity spectrum data with high lateral resolution and well data with high vertical resolution could reconstruct average velocity field of Jurassic main layers. Variable velocity mapping was adopted and new tectonic depth map was compared with former structural map by means of time-depth fitting. Integrating dip logging data、forward modeling technology and ancient landscape restoration method to verify the results of variable velocity mapping. On the basis of variable velocity mapping method, two new micro relief structures were discovered of first member of Qiketai bottom formation; three new micro relief structures were discovered of second member of Sanjianfang bottom formation; two false structures on structural map of first member of Qiketai bottom formation and three false structures on structural map of second member of Sanjianfang bottom formation were revised. Combining wave impedance inversion、attribute analysis and hydrocarbon detection techniques to predict characteristics of reservoir and search favorable low amplitude structural reservoirs, providing theoretical basis for discovering oil and gas reservoir of Putaogou-Pubei area and improving the efficiency of the oil and gas exploration which has have great practical significance.