中国含油气盆地地温-地压系统

地温-地压系统作为盆地流体动力场的耦合，直接控制着油气的运移和聚集。在中国不同类型含油气盆地中，地温-地压系统特征存在很大差异,依据含油气盆地深部和浅部温压系统的斜率关系，划分出3大类地温-地压系统模式：高压型复式温压系统模式（浅部地层压力为静水压力、深度地层压力表现为高压异常）、低压型复式温压系统模式（浅部地层压力为静水压力、深度地层压力表现为低压异常）和单一型温压系统模式（浅部与深部地层压力均为静水压力）。高压型复式温压系统内，浅层系统的斜率分布范围较窄，地区差异小；深层系统的斜率分布范围很宽，地区差异较大。低压型复式温压系统内，浅层系统的斜率分布范围较宽，地区差异很大；深层系统的斜率分布范围较窄，地区差异相对较小。单一型温压系统深、浅层系统的斜率一致且分布比较集中，地区差异不明显。地温-地压系统特征分析表明，高压型复式温压系统内深浅部地层连通性很差，在垂向断裂附近，深层流体向上运移动力很强；低压型复式温压系统内深浅部地层连通性较差，在垂向断裂附近，浅层流体具有向下运移的趋势；单一型温压系统内深浅部地层连通性很好，流体垂向运移动力不足。在中国3大类含油气盆地中，伸展型盆地主要发育高压型复式温压系统,低压型复式温压系统次之；挤压型盆地以高压型复式温压系统为主，也有低压型复式温压系统发育；克拉通盆地发育低压型复式温压系统或高压型复式温压系统。

Characteristics of geotemperature-geopressure systems in petroliferous basins of China

As the coupling of hydrodynamic fields in petroliferous basins, a geotemperature-geopressure system (Geo-TPS) directly controls the migration and accumulation of oil and gas. Studies have showed that characteristics of the Geo-TPS in China differ greatly from one petroliferous basin to another. Based on the relationship of Geo-TPS slopes in shallow and deep formations, three types of Geo-TPS models were put forward: the high-pressure multiple Geo-TPS (HP-MGeo-TPS), the low-pressure multiple Geo-TPS (LP-MGeo-TPS) and the single Geo-TPS (S-Geo-TPS). As for the HP-MGeo-TPS, the slope range of the Geo-TPS is narrower in shallow formations but wider in deep formations. On the contrary, as for the LP-MGeo-TPS, the slope range of the Geo-TPS is wider in shallow formations but narrower in deep formations. And as for the S-Geo-TPS, the slope range of the Geo-TPS is relatively concentrated and regionally identical in both shallow and deep formations. A wider slope range indicates a big variation of the Geo-TPS with different basins, while a narrower slope range means a small change of the Geo-TPS with different basins. The difference of Geo-TPS characteristics suggests that a vertical connectedness in subsurface is better in the S-Geo-TPS than that either in the HP-MGeo-TPS or in the LP-MGeo-TPS. A poor connectedness may lead to an upward migration tendency of deep fluids in the HP-MGeo-TPS but a downward migration tendency of shallow fluids in the LP-MGeo-TPS along vertical fractures. Statistic data show that in China, both the HP-MGeo-TPS and the LP-MGeo-TPS develop well in extensional petroliferous basins; the HP-MGeo-TPS is more common than the LP-MGeo-TPS in compressional basins; and either the LP-MGeo-TPS or the HP-MGeo-TPS occurs in craton basins.