中国叠合盆地深层有利碎屑岩储层的基本类型

Basic Types of High-quality Clastic Reservoirs Deep-buried in Superimposed Basins in China

我国叠合盆地深层碎屑岩的层系多、分布广,是重要的油气赋存单元和勘探目标,而寻找较大规模的优质碎屑岩储层是提高叠合盆地深层勘探效果的重要前提。低热成熟度型、溶蚀孔隙型、裂缝—孔隙型、高抗压—抗热型和高流体压力型等5种类型是深层优质碎屑岩储层,也是我国叠合盆地深层的有利勘探领域。低热成熟度型储层是由晚期快速埋藏和晚期构造推覆引起的,具体受控于盆地的地温梯度、储层热演化轨迹以及构造变形史等;溶蚀孔隙型储层受控于不整合面的发育规模和酸溶条件,可分为大气水淋滤溶蚀以及地层有机酸溶蚀两种类型;裂缝—孔隙型储层往往形成于成岩演化的中—晚期,有构造缝—孔隙型和压裂缝—孔隙型两类;高抗压—抗热型储层主要受控于储层的结构以及刚性组分含量,如石英砂岩和硅质岩屑砂岩等;高流体压力型储层指的是异常地层高压流体的存在对储层成岩演化(包括孔隙演化)的遏制作用,受控于地层流体压力系数的大小及流体异常高压的成因和形成时间。

High-quality clastic reservoirs deep-buried in superimposed basins of China, with many layers and wide distribution, are the importantoil and gas reservoir bodies and exploration targets, which are also key conditions to increase in the exploration effect in seeking for large-scale,high-quality clastic reservoirs in deep superimposed basins. Five reservoir's types, including low-thermal-maturation, solution-pores, fracture-pores, high pressure-resistant and heat-resistant, and high fluid-pressure, are the typical better clastic ones, which are also advantageous explorationtargets of superimposed basins in China. Among these types, the low-thermal-maturation reservoir is formed by rapid burial and overthruststructure in the later period, mainly controlled by the geothermal gradient, the thermal evolution path as well as the structure deformation historyof the basin; Dissolution-pore reservoir may be divided into the meteoric water leaching dissolution and the organic acid dissolution, mainlycontrolled by the scale of unconformity and the condition of acid dissolution; Fracture-pore reservoirs often form in middle-later diagenesisperiod, including structure fracture-pore and crushed fractures pore. High pressure-resistant and heat-resistant reservoir may be mainly controlledby rock structure and the rigid component content, such as quartzose sandstone and siliceous sandstone and so on. Due to the abnormal formationcould restrain the diagenesis evolution of high-pressure-fluid reservoir, so this type are controlled by formation pressure coefficient, the originsand the period of abnormally high pressure fluid originated.