克拉2气田异常高压特征及成因

克拉2气田异常高压的主要特征是：异常高压储层的顶部存在下第三系巨厚的盐岩、膏泥岩盖层，封闭性能良好；含气面积大，储量高；断层对气藏的形成和保存起关键作用。本研究区异常高压形成的主控因素是构造抬升和水平构造挤压应力。喜山晚期构造运动导致地层大幅抬升，遭受剥蚀而垂向、侧向上良好的封闭性使得孔隙流体压力得以保存；侧向挤压应力又加剧了异常高压的程度。

CHARACTER AND ORIGIN OF OVERPRESSURE IN KELA 2 GAS FIELD

The overpressured Kela 2 gas field is characterized by: overpressured reservoir intervals overlain by very thick salt and gypsum-argillaceous beds of the Paleogene which are of good sealing capability; wide extent of gas-bearing area and very large reserve; key roles played by faults in pool-forming and gas accumulation. Tectonic uplift and lateral compression are major factors responsible for the abnormal pressure. Late Himalayan movement caused formation uplift and denudation, whereas the pore pressure was maintained by vertical and lateral sealing boundaries, resulting in development of overpressure. Later, this overpressure was further enhanced by the lateral compression stress.