Abstract: The Keshen gas field is located in the central part of Kuqa depression in Tarim Basin, and is another large gas field discovered after Kela2 gas field. Since the breakthrough in 2008, a number of large and medium scale gas reservoirs including Keshen2, Keshen5 and Keshen8 have been discovered in Keshen gas field. These gas reservoirs are characterized by ultra-depth, ultra-high pressure, ultra-low porosity and permeability, high temperature and pressure. With natural gas geological reserves of nearly trillion cubic meters and production capacity of nearly 100×10⁸m³, the Keshen gas field is the main natural gas producing area in Tarim oilfield. The Keshen gas field is located in imbricate thrust structures in the Kelasu structural belt of Kuqa depression. Its structure includes the supra-salt overburden, the ductile salt rheological layer and the large wedge-shaped thrust body composed of the pre-salt faulted anticline group. The thick delta sandstones of Cretaceous Bashijiqike Formation are widely distributed in Keshen gas field, which formed the superior reservoir-caprock assemblage with the overlying Paleogene thick gypsum-salt bed. Oil and gas in Triassic and Jurassic source vertically migrate along the fault system in Late Himalayas, break through the thick Cretaceous mudstone, and laterally transported along the fracture system of the pre-salt reservoirs, thus forming anticline and fault-bend high-pressure reservoir groups. The three-dimensional seismic acquisition and processing technology for complex mountain areas, the compacted salt-related structural modeling technology, and the fractured low-porosity sandstone reservoir evaluation technology have laid a foundation for the implementation of exploration targets in Keshen gas field. Logging acquisition and evaluation technology for high temperature, high pressure, ultra-deep and low-porosity sandstone gas reservoirs, and efficient development technology for fractured tight sandstone gas reservoirs provide technical supports for efficient exploration and development and rapid production of Keshen gas field.

Key words: Tarim Basin, Keshen gas field, three-dimensional mountainous seismic exploration, hydrocarbon accumulation, ultra-deep high temperature and high pressure gas reservoirs, efficient exploration and development

摘要： 克深气田位于塔里木盆地库车坳陷中部，是继克拉2气田之后发现的又一大型气田。自2008年获得重大突破以来，克深气田相继发现了克深2、克深5和克深8等一批大—中型气藏，这些气藏具有超深、高压—超高压、特低孔和中—低渗等特征，其天然气地质储量达万亿立方米，建成产能近100×10⁸m³，是塔里木盆地的天然气主力产区。克深气田位于库车坳陷克拉苏构造带的叠瓦逆冲构造中，其结构包括由盐上顶蓬构造、塑形流变的盐岩以及盐下断背斜构造群构成的大型楔形冲断体。克深气田的白垩系巴什基奇克组三角洲砂岩广泛分布，与上覆古近系巨厚膏盐层形成优越的储-盖组合；深层三叠系—侏罗系的油气沿喜马拉雅晚期成排成带的断裂体系垂向运移，沿盐下储集层内的裂缝体系横向输导，从而形成背斜、断背斜型高压油气藏群。复杂山地三维地震采集处理、挤压型盐相关构造建模和裂缝型低孔砂岩储层评价等技术为克深气田勘探目标的落实奠定了基础；高温高压超深层低孔砂岩气藏测井采集与评价、裂缝型低孔砂岩气藏高效开发等技术为克深气田的高效勘探开发和快速上产提供了技术保障。

关键词: 塔里木盆地, 克深气田, 山地三维地震勘探, 油气成藏, 超深层高温高压气藏, 高效勘探开发