塔中北坡奥陶系鹰山组热液改造型储层特征及发育模式

Characteristics and development model of hydrothermal alteration reservoir of Ordovician Yingshan Formation in northern slope of central Tarim Basin

韩俊 吕海涛 曹自成 邱华标 王保才 沙旭光 刘军

Han Jun Lü Haitao Cao Zicheng Qiu Huabiao Wang Baocai Sha Xuguang Liu Jun

中国石化 西北油田分公司 勘探开发研究院, 乌鲁木齐 830011

Research Institute of Petroleum Exploration and Production, SINOPEC Northwest Company, Urumqi, Xinjiang 830011, China

塔中北坡中下奥陶统鹰山组碳酸盐岩发育热液石英、板条状石膏、鞍型白云石等典型的低温热液矿物组合.对不同类型的石英包裹体测温,其温度范围明显高于地温演化的最高温度.分析了典型钻井鹰山组储层分布与本区潜在不整合面的关系,认为鹰山组储层为热液改造成因,与大气水岩溶作用关系不大.鹰山组热液改造型储层储集空间以孔洞(洞穴)、(扩溶)裂缝等次生储集空间为主,基质物性总体低孔低渗,可划分为洞穴型、孔洞—裂缝型和孔隙型3种类型.分析了鹰山组热液改造型储层的主控因素,提出断裂—裂缝体系是储层发育的前提条件,加里东晚期—海西期北东向、北东东向主干走滑断裂及次级隐伏断裂控制储层平面分布,深部热液流体改造储层,流体性质及岩性结构可能控制了储层纵向分布,初步建立了储层发育模式.该类储层发育厚度大,且受埋深影响不大,沿主干、次级断裂广泛发育,是塔里木盆地碳酸盐岩天然气勘探的一个新领域.

In the Middle-Lower Ordovician Yingshan Formation in the northern slope of the central Tarim Basin, typical epithermal hydrothermal mineral assemblages, such as hydrothermal quartz, lath gypsum and saddle dolomite, were found in carbonate rocks. For different types of quartz inclusions, measured temperature was significantly higher than maximum evolution temperature. The relation between the Yingshan reservoir distribution in typical wells and the potential unconformities in the study area was studied, indicating that the Yingshan reservoirs generated from hydrothermal alteration, rather than the karstification of meteoric water. The main space of the Yingshan reservoirs was secondary hole (cave) and expansion fracture, with low porosity and permeability. They were divided into 3 types: hole type, hole-fracture type and pore type. Analysis of the main controlling factors of hydrothermal alteration reservoir showed that fault-fracture system was a precondition for reservoir deve-lopment, and the NE and NEE main strike-slip faults of the late Caledonian-Hercynian and the secondary faults controlled the plane distribution of hydrothermal reservoir. Deep hydrothermal fluid altered reservoir, and fluid properties and reservoir lithologic structure controlled the vertical distribution of hydrothermal reservoir. The development model of hydrothermal alteration reservoir was established. Hydrothermal alteration reservoirs, which were featured by big thickness, little affected by depth, and widely developed along main and secondary faults, were new gas exploration fielda of carbonate rocks in the Tarim Basin.

https://doi.org/10.11781/sysydz2014S1018