关键词: 库车前陆盆地, 地震勘探技术, 潜伏背斜气田, 发现, 开发, 精细地震勘探

Abstract: In the Kuqa foreland basin, the buried anticlines are the primary exploration targets, and they are usually discovered and ascertained with seismic exploration technologies. Throughout the oil and gas exploration history of the Kuqa foreland basin, the development of seismic exploration technologies under went four stages: 1) seismic crooked line survey – poststack time migration; 2) seismic straight line survey – poststack/prestack time migration; 3) seismic wide line survey – prestack time/depth migration; and 4) 3D seismic wide azimuth survey – anisotropic prestack depth migration. Thanks to new seismic exploration technologies and methods, the signal to noise ratio and migration imaging accuracy of the seismic data have been improved gradually, and numerous buried subsalt anticline traps in the Cretaceous system were discovered and ascertained. Most of these traps are distributed in the Dabei-Keshen area, and they are mainly large and medium gas fields, forming gas field clusters in the buried anticlines. It is shown that the seismic exploration technologies play a positive role in solving the four problems constraining the seismic exploration in the Kuqa foreland basin, namely, low S/N ratio in diluvial fans, serious static correction problem derived from the rugged topography, poor imaging quality of subsalt structures, and velocity pitfall caused by gravel layers. As the development of buried anticlines in the Kuqa foreland basin proceeds into the middle and late stages, the development is becoming more and more difficult, thus finer seismic exploration technologies are required. Especially, the single point, high density and wide azimuth 3D seismic exploration technology and anisotropic prestack depth migration technique will be the top concerns.

Key words: Kuqa foreland basin, seismic exploration technique, buried anticline gas field, discovery, development, fine seismic exploration