Logging Evaluation of the Ordovician Carbonate Reservoir Beds in the Lungudong Region,Tarim Basin

In recent years, great progress has been made constantly in oil and gas exploration in the Lungudong region of the Tarim Basin. However, progress has been slow in the evaluation of its main oil-producing horizons -- the Ordovician carbonate reservoir beds. Based on previous researches and on the various data such as drilling, geology and oil test, in combination with the interpretation of each single-well imaging and conventional logging data, and through analysis and comparison, the identification methods in imaging and conventional logging for four types of carbonate reservoir beds in this region are summarized in this paper. Calculation formulas for four reservoir bed parameters, i. e. shale content, porosity, permeability and oil saturation in this region are proposed; and reservoir beds in this region are divided into three levels （Ⅰ, Ⅱ and Ⅲ） by combining oil test data and logging data, The lower limits of the effective porosity of reservoir beds and the fracture porosity of effective reservoir beds are determined as 1.8% and 0.04%, respectively. The physical property parameters are calculated by conventional logging curves, and the most advantageous areas for reservoir development are predicted comprehensively. On the plane, the high-value zones of reservoir bed parameters are mainly concentrated in the N-S-trending strike-slip fault, the Sangtamu fault horst zone and near the LG38 well area; vertically, the reservoir bed parameters of the Yijianfang Formation are better than those of the Yingshan and Lianglitage formations.

Ordovician Carbonate Reservoir Bed Characteristics and Reservoir-Forming Conditions in the Lungudong Region of the Tarim Basin

Basic characteristics of Ordovician carbonate reservoir beds in the Lungudong region of northeastern part of the Tarim Basin are described in detail and the reservoir-forming conditions of oil and gas are preliminarily discussed in this paper by collecting and sorting out a large amount of data. The carbonate reservoir beds are mainly developed in open-platform and platform marginal facies; the reservoir beds have large changes in and low average values of physical property; the main type is fractured reservoir beds with the fracture-porous type second. The reservoir bed development is chiefly controlled by the distribution of sedimentary facies, tectonic activity and karstification. Whereas the accumulation and distribution of hydrocarbons in the region are controlled by an advantageous structural location, a good reservoir-caprock combination and a favorable transporting system, with the distribution characterized by zones horizontally and belts vertically, the oil and gas are mainly concentrated in areas with structural uplift, densely developed fractures, and surface karst, a vertical vadose zone, and a horizontal undercurrent belt of palaeokarst.

轮古东走滑断裂破碎带结构及与油气关系

利用最新处理完成的轮古东300 km2叠前深度偏移地震资料,多手段识别出轮古东气田发育3期4组断裂。断裂控制了裂缝走向与裂缝发育密度,裂缝主要为高角度（45°~75°）构造窄裂缝,沿裂缝存在溶蚀,走向主要为NESW。纵向上,一间房组裂缝发育密度最大（14条/100 m）,其次为鹰山组（6条/100 m）和良里塔格组（4条/100 m）;平面上,裂缝主要分布在主干断裂周边1 km范围内,随着距断裂距离增大,裂缝发育强度（裂缝线密度）呈指数降低。在此基础上,综合考虑主干断裂及伴生裂缝发育特征,将轮古东断裂破碎带平面上划分为“羽状破碎带、转换破碎带、斜列破碎带、复合破碎带”4种结构,羽状破碎带分布面积最广,是油气最富集的区域,是目前高效井的集中分布区,围绕羽状破碎带的钻探为走滑断裂控储控藏研究和寻找新的油气富集区域提供了新思路。

塔里木盆地轮古东地区奥陶系碳酸盐岩储集层发育控制因素及有利区带预测

为探讨塔里木盆地轮古东地区奥陶系碳酸盐岩储集层发育的控制因素和寻找有利储集层的分布规律,作者分析了近几年该区的油气勘探资料,恢复了研究区的构造演化历史。研究结果表明,构造活动所引起的地层抬升、变形以及断裂作用对于碳酸盐岩形成岩溶型储集层及改变储集层原有物性起着建设性作用;优势沉积相的平面展布控制研究区油气藏的分布;加里东期存在2套风化壳岩溶,这2套岩溶制约了与岩溶有关的储集层分布,主要分布在表层岩溶至水平潜流带区域。根据碳酸盐岩储集层发育的控制因素,预测了有利储集层的分布,认为有利区带主要分布在研究区内2条大的走滑断裂以及桑塔木断垒带附近。

新疆塔里木盆地轮古东气田良里塔格组沉积特征及其与油气关系

为探讨塔里木盆地轮古东地区上奥陶统良里塔格组礁滩体灰岩的沉积模式、储集层特征和油气富集规律,开展了新一轮气藏精细描述研究。结果表明,良里塔格组自下而上可分为瘤状灰岩段和颗粒灰岩段,沉积环境属远端变陡的无镶边缓坡型碳酸盐岩台地沉积;储集层主要发育于颗粒灰岩段,为低孔中低渗层状裂缝-孔洞型储集层,储集层的发育主要受岩性、岩溶风化壳及断裂的控制;油气以垂向断裂与礁滩体储集层为纵横向输导体系,主要分布于主干断裂及多期断裂交汇部位的断裂破碎带附近。

轮古东奥陶系凝析气藏水体能量评价研究

轮古东奥陶系凝析气藏发育多套产层,纵横向油水关系复杂,多数井水淹后,油对气采出程度低,累计产量低,严重制约了该气藏的规模开发。通过对大量资料的分析,利用压降曲线法、体积平衡原理和水侵体积系数法等多种方法完成了水体定量评价研究,建立了定量评价标准。对水体纵横向分布特征进行总结:横向上水体能量强弱不等,整体呈现工区南部的水体能量强于北部的趋势,具体表现为轮南断垒带水体能量较强,而沿轮东走滑断垒带西侧的区域水体能量表现为中等,水体能量较弱的区域则为桑塔木断垒带;纵向上鹰山组水体能量要强于一间房组,比一间房组更易出水。

塔里木盆地轮古东地区油气相态及饱和度的主控因素

塔里木盆地轮古东地区的油气主要为凝析气藏,但与常规凝析气藏又有所不同,且不同凝析气藏间饱和状态也存在差异。研究认为:轮古东凝析气藏具有"气干油重"的特征,可分为未饱和、饱和两种凝析气藏,未饱和凝析气藏主要分布在走滑断裂附近和充注强度大的区域,饱和凝析气藏主要分布在断裂不发育和充注强度较弱的区域;凝析气藏相态的主控因素是经历多期成藏、发育大型深部断裂、充注强度变化及良好的盖层保护。