Abstract:

Fractured-vuggy carbonate reservoirs represent a major domain in global hydrocarbon exploration and development. However, their efficient development is constrained by strong heterogeneity, characterized by spatially discrete distribution of fractures and vugs, complex connectivity, and diverse filling types. This paper systematically reviews research advances in reservoir characteristics, experimental methods, remaining oil distribution, and water/gas injection mechanisms. Based on genesis and controlling factors, the reservoirs are classified into three types: (1) Epikarst: dominated by fractures and dissolution pores (depth < 70 m), with a filling ratio of up to 60%; (2) Subterranean river karst: characterized by large-scale dissolution caves (extending 0.8 ~ 3.5 km), which are further divided into four types based on cave height: hall caves, main channel caves, tributary caves, and terminal caves; (3) Fault-controlled karst: forming vertically connected “fracture-cavity complexes” along fault zones, with full filling ratios ranging from 20% to 38%. Physical experimental models have evolved from conceptual ones (e.g., spliced marble/acrylic plates) toward realistic structures: marble models reveal fundamental flow mechanisms; transparent acrylic models enable visualization of displacement processes; laser-etched models replicate complex fracture-vug networks; full-diameter leached core samples support high-temperature and high-pressure simulations; and 3D printing allows precise control of fracture-vug morphology. However, limitations remain in simulating diverse filling media. After water flooding, remaining oil occurs in various forms, including attic oil, blind-end oil, bottom-water coning oil, oil shielded by high-conductivity channels, and filling-dependent oil. Field analyses, numerical simulations, and physical experiments consistently indicate that attic oil accounts for the largest proportion, making it a key target for enhanced oil recovery. Development strategies have progressed from single-well huff-and-puff to multi-well water/gas flooding, and further to optimized synergistic gas-water injection. Specifically, single-well water flooding mainly reduces water-coning residual oil; gas huff-and-puff mobilizes attic oil via gravity segregation; bottom-water injection suppresses coning and expands sweep efficiency; nitrogen flooding effectively recovers attic oil but requires well pattern optimization to control gas channeling; cyclic water injection enhances water diffusion through pressure fluctuations; flow-reversal injection alters flow paths to enlarge sweep volume; and synergistic gas-water injection couples gravity segregation with mobility control to improve displacement efficiency. Based on these insights, this paper proposes an integrated framework for potential tapping, termed “reservoir-specific adaptation, remaining oil targeting, stage-wise optimization”. This framework entails precisely matching injection-production techniques to reservoir types, implementing targeted controls based on remaining oil patterns, and dynamically optimizing strategies according to development phases. Future efforts should address challenges in three-dimensional modeling of complex fracture-vug systems, suppression of gas channeling, and dynamic prediction of remaining oil. Integrating artificial intelligence and high-precision detection technologies will enable accurate characterization of fracture-vug architectures. Developing novel experimental materials and model fabrication techniques will enhance simulation authenticity. Constructing numerical models that account for multi-physics coupling and optimizing synergistic gas-water flooding strategies are crucial for advancing the development of fractured-vuggy reservoirs from an “experience-driven” to a “precision-controlled” paradigm.

Key words: carbonate fracture-vuggy reservoir, water injection, gas injection, reservoir characterization, physical experiment, remaining-oil distribution, development mechanism

摘要：

缝洞型碳酸盐岩油藏是全球油气勘探开发的重要领域，但其强非均质性(缝洞空间离散分布、连通关系复杂及充填类型多样)制约了高效开发。本文系统综述了储层特征、实验方法、剩余油分布及注水注气机理的研究进展。基于成因及主控因素，储层划分为3类：(1)表层岩溶：以裂缝和溶蚀孔洞为主(深度<70 m)，充填率高达60%；(2)暗河岩溶：发育大型溶洞(延伸0.8~3.5 km)，按洞高分为厅堂洞、干流洞、支流洞及末梢洞等4类；(3)断控岩溶：沿断裂带形成垂向连通的”缝洞复合体”，全充填率为20%~38%。驱油物理实验模型从概念模型(大理石/有机玻璃拼接)向真实结构迭代：大理石模型揭示基础流动机理，透明有机玻璃模型实现驱替可视化，激光刻蚀模型复现复杂缝洞网络，全直径溶蚀岩芯支持高温高压模拟，3D打印技术精准控制缝洞形态，但模拟多类型充填介质时仍存局限。水驱后剩余油多种多样，有阁楼型、盲端型、底水锥进型、高导流通道屏蔽型及充填依赖型等。矿场分析、数值模拟与物理实验都表明阁楼油占比最高，是提高采收率的关键靶目标。开发策略已由单井吞吐演进为多井注水、注气驱替，并进一步发展为气水协同注入优化。注水替油主要减少水锥剩余油；注气吞吐通过重力分异动用阁楼油；底部注水抑制水锥并扩大波及体积；氮气驱有效动用阁楼油，但需优化井网以控制气窜；周期注水通过压力波动促进水扩散；换向注水可改变流道方向扩大波及范围；气水协同耦合重力分异与流度控制，提升驱油效率。基于上述认识，本文进一步提出了“储层适配—剩余油靶向—阶段优化”的一体化挖潜体系：按储层类型精准适配注采工艺，按剩余油类型实施靶向调控，按开发阶段动态优化策略。未来，需突破复杂缝洞系统三维建模、气窜抑制及剩余油动态预测等难题，结合人工智能、高精度探测等技术，实现缝洞结构的精准表征，开发新型实验材料与模型制作工艺，提高模拟的真实性；构建考虑多场耦合的数值模型，优化气水协同驱替策略，推动缝洞型油藏开发从“经验驱动”向“精准调控”转变。

关键词: 碳酸盐岩缝洞型油藏, 注水开发, 注气开发, 储层特征, 物理实验, 剩余油分布, 开发机理

CLC Number: 

• TE344

• TE122