Gas Reservoir Detection And Trap Analysis Of Eastern Yakela Fault Arch In Tarim Basin

Yakela fault arch in Shaya uplift is the potential exploration area in the Tarim Basin. Kuche and Luntai research areas covered by 3D seismic dataset are located in the south of Kuche Depression and the east of Yakela fault arch. Anticlines developed in the research area. With suitable source rock, reservoir, and cap rock combinations,tectonic gas traps were found in the area. But currently non-tectonic gas reservoir exploration is the exploration target because large tectonic reservoirs are less and less.Based on core samples, log data and seismic data,a new frequency attenuation attribution was used in the paper to explore predicted gas reservoirs. Then petroleum geological condition of the gas reservoirs was analyzed. The possibility of gas reservoirs in Cambrian, Jurassic and Paleogene was evaluated. The conclusions are as follow:The Jurassic slope in the north of Luntai research area is about 300 meters in the thickest area. No anticline developed in the research strata. On the frequency attenuation attribution map, two anomalies showing predicted gas reservoir were found. The No. 1 oval anomaly is about 20 km2, and the value of the anomaly is 10-20(without unit) indicating favorable gas potential. The No. 2 banded anomaly is about 10 km2 and the value is 8-15(without unit). The No. 2 anomaly covers the sand distribution area in the RMS attribution map implying higher possibility. Considering the stratigraphic overlap, wedging out and petroleum geology, the No. 1 anomaly is predicted to be strata-pinchout gas reservoir and No. 2 to be stratigraphic overlap gas reservoir.Carbonate rocks were widely developed in Cambrian in the Kuche area. The type of reservoir in the strata is considered to be emposieu. The No. 3 anomaly is about 10 km2, and the value of the anomaly is about 14-20 (without unit). The north and south border of the anomaly is controlled by faults which are parallel to the borders. This anomaly is predicted to be caused by the gas storage in the carbonate rock.Sand body in Kumugeliemu Formation was largely distributed in Cenozoic of the Kuche area. The anomaly in frequency attenuation attribution was also found in the strata. But the distribution of the anomaly has no apparent relationship with fault and tectonic line. There is no possibility for the anomaly to be gas reservoir from its petroleum geological condition. The anomaly may be caused by sand rock with lower speed.A new method for non-tectonic gas reservoir exploration is put forward in the paper. Higher reliability of this method was identified by project cases, so it is believed that the method will improve non-tectonic gas reservoir exploration possibility.