天山南缘从柯坪阿恰经巴楚三叉口到巴楚五道班的100余公里的316国道北侧的奥陶系中发育了一条1~2km宽的碳酸盐岩岩溶带。在该带的鹰山组中发育了一条900m宽的风化壳沉积(古土壤)和约30多个大型古溶洞。其中以硫磺沟2号溶洞最为典型,该溶洞位于一个很窄的倾角大于70°的走滑断裂带内,古钙华一般产在溶洞和裂缝中,作为充填体出现。硫磺沟2号溶洞的古钙华多呈黄褐色-黑色,普遍含石油。古钙华纹层发育,根据结构、颜色及形态等可以分为六种,分别为层状纹层、波状纹层、包壳状纹层、束状纹层、丘状纹层或半球形丘状纹层和杂乱纹层,这些纹层的形态和结构特点反映了其成因与菌藻或微生物有关;构成纹层的方解石主要为针状、柱状、细晶状和粗晶状等。钙华方解石晶体之间缝隙和孔隙非常发育,是良好的储集空间和运移通道。物性研究表明,硫磺沟2号溶洞古钙华的孔隙度介于3.81%~13.91%之间,平均7.21%,从孔隙度值来看属于致密储层(10%);但渗透率很大,介于(2.99~87.60)×10~(-3)μm~2之间,平均48.99×10~(-3)μm~2,从渗透率看是一种较好的储层。出现这种“反常”的情况与古钙华特殊的内部结构有密切关系,钙华以晶间缝为主,具有紧密堆积的结构,虽然孔隙度不大,但是晶间缝在三维上构成了网络系统,导致渗透性很好,被称之为“致密高渗”储层。通过对塔里木盆地北部柯坪奥陶系露头硫磺沟2号溶洞及现代九寨沟溶洞的研究,发现岩溶过程中的化学沉积形成的钙华具有重要的石油地质意义,主要表现在两个方面:一是钙华是很好的储集空间;二是钙华具有一定的生烃能力。文章旨在探讨塔里木盆地奥陶系露头钙华相、钙华岩石学及钙华地球化学证据,以支持钙华的形成过程和形成环境的解释、及对塔河油田奥陶系缝洞油气藏的储集空间和油气成藏意义。 On the southern margin of Tianshan, a carbonate rock karst zone 1 ~ 2 km wide is developed in the Ordovician on the north side of No.316 National Highway from 100 km to the 5 classes of Bachu from Keping Aqiao Bachu Port. A 900-m-wide weathered crust (ancient soil) and about 30 large paleokarst caves were developed in the Yingshan Formation of the belt. Among them, the most typical karst cave in Sulfur Rift 2 is located in a narrow strike-slip fault zone with an inclination greater than 70 °. The ancient travertine is generally found in karst caves and fractures and appears as a filling body. Sulfur Cave No. 2 karst cave is mostly brown - black, generally containing oil. The development of the ancient travertine layer, according to the structure, color and morphology can be divided into six kinds, namely lamellar layer, wavy layer, cladded layer, bundle layer, mound layer or hemispherical mound The patterns and structural features of these laminae reflect the genesis of the lamina and algae or microorganisms. The calcite that forms lamina is mainly acicular, columnar, fine-crystalline and coarse-crystalline. Travertine calcite crystal gap between the pore and very developed, is a good storage space and migration channels. Physical properties show that the porosity of the ancient travertine in Sulixou No.2 caverns ranges from 3.81% to 13.91% with an average of 7.21%, which belongs to the tight reservoir (10%) from the porosity value. However, the permeability is very high, (2.99 ~ 87.60) × 10 ~ (-3) μm ~ 2 with an average of 48.99 × 10 ~ (-3) μm ~ 2, which is a good reservoir from the perspective of permeability. The occurrence of such “abnormal” is closely related to the special internal structure of the ancient travertine. The travertine is dominated by intergranular seams and has a closely packed structure. Although the porosity is not large, the intergranular cracks are sewn in three dimensions Constitute a network system, resulting in good permeability, is called “tight hypertonic ” reservoir. Based on the study of the Ordovician outcrop sulfur cave No. 2 and the modern Jiuzhaigou caves in the northern part of the Tarim Basin, it is found that the travertine formed by chemical deposition during the karstification process has important petroleum geological significance, which mainly manifests in two aspects: firstly, Travertine is a good storage space; the second is travertine has a certain capacity of hydrocarbon generation. The purpose of this paper is to investigate the Ordovician outcropping travertine, travertine petrology and travertine geochemistry in the Tarim Basin to support the formation and formation of travertine and to explain the formation of Ordovician fractured vugs in the Tarim Basin The reservoir space and hydrocarbon accumulation significance.