Abstract: The observation and measurement of cores,thin slices,casting body slices,cathode luminescence and FMI well logging interpretations indicate that fracture systems with clear cyclicity in vertical direction are developed in the Ordovician reef-bank complex in Shunxi area of the central Tarim Basin and divided into vertical fracture,high-angle fracture and horizontal fracture in the morphology.According to the multi-period composite and superimposed characteristics of fracture origin,the fracture systems can also be divided into non-structural genetic fracture and structural genetic fracture.The later can be mechanically classified into tensile fracture,tensile-shear fracture and shear fracture.Some fractures are filled by sparry calcite,some ones are half-filled,and some ones are unfilled.The unfilled and half-filled fractures are well developed and have significant role for hydrocarbon storage and accumulation.According to filling characteristics and incised relationships between fractures as well as regional tectonic evolution history,the structural genetic fracture can be further divided into three stages,including the late Caledonian-early Hercynian stage,late Hercynian-Indosinian stage and Yanshanian-Himalayan stage.The development of fracture is mainly controlled by mechanical property of limestone,tectonic stress field,tectonic movement,fault activity and volcanism.

Key words: central Tarim Basin, Ordovician, reef-bank complex, fracture characteristics, controlling factors

摘要： 对岩心、薄片、铸体薄片的观察及阴极发光、成像测井的解释结果表明,塔中顺西区块奥陶系良里塔格组礁滩复合体发育复杂的裂缝系统,按其形态可分为垂直裂缝、高角度裂缝和水平裂缝。该裂缝系统在纵向上存在明显的旋回性发育,在成因上具有多期复合叠合的特点。根据其成因,可以分为非构造成因裂缝和构造成因裂缝。根据力学属性,构造成因裂缝又可分为张性裂缝、张剪性裂缝和剪切裂缝。裂缝部分被方解石完全充填或半充填,部分未被充填而呈开启状,其中以未充填或半充填的高角度裂缝较发育,对油气储聚具有重要作用。根据裂缝充填特征和切割关系,结合区域构造演化史,构造成因裂缝可划分为晚加里东期—早海西期、晚海西期—印支期和燕山期—喜山期3个成因期次。裂缝的发育主要受岩石自身力学特性、构造应力场、构造运动、断裂活动及火山作用的控制。

关键词: 塔中地区, 奥陶系, 礁滩复合体, 裂缝特征, 控制因素