塔中Ⅰ号断裂带O_(2+3)灰岩储层裂缝特征

CHARACTERISTICS OF O_(2+3) LIMESTONE RESERVOIR RIFT IN TAZHONG 1# FRACTURE ZONE

塔中Ⅰ号断裂带O2 + 3 灰岩储层裂缝可分为构造裂缝和非构造裂缝两大类。根据裂缝交切关系、方解石包裹体均一温度和岩石Kaiser实验结果 ,认为O2 + 3 灰岩遭受 3次构造运动 ,形成了相应的 3期构造裂缝。晚加里东 -早海西期 ,在静压力作用下 ,沿O2 + 3 灰岩层面形成平行层面的成岩裂缝 ,之后 ,在NE -SW向构造力作用下 ,产生一系列垂直层面的共轭剪切缝、高角度缝合线以及随应力积聚而形成的纵张、横张缝等 ,此期裂缝均为方解石充填 ;晚海西期 ,构造运动将前期裂缝扩大 ,并产生新的剪切裂缝 ,后期相对宁静 ,裂缝被半透明状方解石充填 ;喜山期再次受到构造运动影响 ,形成了规模不大、方向性好、基本未被充填的直立构造剪切缝 ,对油气的运聚有重要作用。

O 2+3 limestone reservoir rift in Tazhong 1# fracture zone can be divided into two types of structural rift and non-structural rift.It is believed that,on the basis of intersected relations of the rift and testing results of homogeneous temperature of calcite packet and rock Kaiser,O 2+3 limestone had gone through three times of tectonic movements,forming corresponding 3 phases of structural rifts.During the period of Late Caledonian and Early Hercynian,after the formation of diagenetic rift of paralle-bedding plane along O 2+3 limestone plane in the process of static pressure and in the process of NE-SW structure,a series of conjugate shear rifts of vertical bedding plane,high-angle stylolites as well as longitudinal and transverse tensional rifts due to accumulation of stress.The rifts of this period are filled with calcites.During Late Hercynian,early rifts were enlarged by the tectonic movements and new shear rifts were produced.In the late period of Late Hercynian,the tectonic movements were relatively static,rifts were filled with semitransparent calcites.Unfilled vertical structural shear rifts with good orientation of non-big scale were formed by the influence of the tectonic movements again during Himalayan period which played very important role in hydrocarbon accumulation.