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塔西南坳陷卡拉塔尔组储层特征及控制因素

Reservoir Characteristics and Controlling Factors of the Paleogene Kalatar Formation in the Southwestern Tarim Depression

何光芒

Environment and Resource / 2026,8(8): 370-377 / 2026-08-19 17 14

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• Information:

  东华理工大学地球物理与空间探测学院，南昌

• Keywords:
  Southwestern Tarim Depression; Kalatar Formation; Carbonate reservoir; Sedimentary facies; Diagenesis; Controlling factors
  塔西南坳陷; 卡拉塔尔组; 碳酸盐岩储层; 沉积相; 成岩作用; 控制因素
• Abstract: The Southwestern Tarim Depression is an important Mesozoic–Cenozoic foreland basin along the margin of the Tarim Basin. Hydrocarbon shows have been encountered in the Paleogene Kalatar Formation, whereas a region-wide synthesis of its sedimentary and reservoir characteristics remains limited. Based on four measured outcrop sections, six reconnaissance sections, and data from 14 wells, this study integrates outcrop and core observations, cuttings identification, conventional and casting thin-section analyses, scanning electron microscopy, cathodoluminescence, and petrophysical measurements to investigate sedimentary facies, diagenesis, reservoir space, physical properties, and the principal controls on reservoir development. The Kalatar Formation was deposited in an Eocene embayment and records two depositional systems: mixed shore–shelf deposits and a carbonate ramp, reflecting contrasting terrigenous input from the South Tianshan and West Kunlun mountains. Reservoir rocks are dominated by oolitic, intraclastic, and bioclastic limestones and dolostones. Pore space includes interparticle, intraparticle, intercrystalline, moldic, shelter, framework pores, fractures, and minor vugs; secondary dissolution pores and fractures are dominant, defining a fractured–porous reservoir. Oolitic limestone and dolostone show relatively high average porosity of approximately 8%–10%, whereas mid-ramp shoals commonly have average porosity of 8%–10% and permeability of 2–3 mD. Porosity is weakly correlated with permeability (R²=0.2363) but better correlated with thin-section areal porosity (R²=0.601), indicating that pore-throat architecture and fractures exert an important influence on flow capacity. High-energy shoal facies, dolomitization, and dissolution constitute the principal geological elements controlling high-quality reservoir development, and structural fractures locally improve connectivity. The northern Kashgar Sag, the margin of the Qimugen Uplift, the Kekeya area, and the Maigaiti Slope are considered relatively favorable exploration areas. 塔西南坳陷为塔里木盆地周缘重要的中—新生代前陆盆地，古近系卡拉塔尔组已有多口钻井见油气显示。前人已开展局部区块研究，但尚未形成覆盖全区的系统性沉积、储层综合认识。本文以4条详测剖面、6条观察剖面和14口钻井资料为基础，综合运用露头与岩心观察、岩屑鉴定、普通薄片与铸体薄片分析、扫描电镜、阴极发光及物性测试等手段，系统研究卡拉塔尔组的沉积相、成岩作用、储集空间、物性特征及储层发育主控因素。结果表明：卡拉塔尔组总体形成于始新世海湾环境，受南天山与西昆仑山陆源碎屑供给差异影响，发育滨岸—陆棚混积和碳酸盐岩缓坡两类沉积模式。主要储集岩为鲕粒灰岩、砂屑灰岩、生屑灰岩和白云岩，储集空间包括粒间孔、粒内孔、晶间孔、铸模孔、遮蔽孔、生长骨架孔、裂缝及少量晶洞，其中次生溶蚀孔隙和裂缝较为重要，整体表现为裂缝—孔隙型储层。不同岩性物性差异明显，鲕粒灰岩和白云岩平均孔隙度相对较高，约为8%～10%；中缓坡浅滩平均孔隙度可达8%～10%，平均渗透率约为2～3mD。全样品孔隙度与渗透率相关性较弱（R2=0.2363），孔隙度与面孔率相关性较好（R2=0.601），表明孔喉结构与裂缝发育对渗流能力具有重要影响。高能浅滩相、白云岩化和溶蚀作用是控制优质储层发育的核心地质要素，构造裂缝可进一步改善渗流条件，而泥晶充填、方解石胶结及压实—压溶作用会造成孔隙损失。喀什凹陷北部、齐姆根凸起周缘、柯克亚地区和麦盖提斜坡为相对有利勘探区，其中中缓坡鲕粒滩、生屑滩及白云岩化颗粒岩可作为优先评价目标。
• DOI: 10.35534/er.0803053 (registering DOI)
• Cite: 何光芒．塔西南坳陷卡拉塔尔组储层特征及控制因素［J］．环境与资源，2026，8（3）：370-377.