Naturally fractured reservoirs are important contributors to global petroleum reserves and production. Existing classification schemes for fractured reservoirs do not adequately differentiate between certain types of fractured reservoirs, leading to difficulty in understanding fundamental controls on reservoir performance and recovery efficiency. Three hundred naturally fractured reservoirs were examined to define a new classification scheme that is independent of the type of fracturing and describes fundamentally different matrix types, rock properties, fluid storage and flow characteristics. This study categorises fractured reservoirs in three groups: 1) Type 1: characterized by a tight matrix where fractures and solution-enhanced fracture porosity provide both storage capacity and fluid-flow pathways; 2) Type 2: characterized by a macroporous matrix which provides the primary storage capacity where fractures and solution-enhanced fracture porosity provide essential fluid-flow pathways; and 3) Type 3: characterized by a microporous matrix which provides all storage capacity where fractures only provide essential fluid-flow pathways. Differentiation is made between controls imparted by inherent natural conditions, such as rock and fluid properties and natural drive mechanisms, and human controls, such as choice of development scheme and reservoir management practices. The classification scheme presented here is based on reservoir and production characteristics of naturally fractured reservoirs and represents a refinement of existing schemes. This refinement allows accurate comparisons to be made between analogous fractured reservoirs, and trends and outliers in reservoir performance to be identified. Case histories provided herein demonstrate the practical application of this new classification scheme and the benefits that arise when applying it to the understanding of naturally fractured reservoirs.

中文翻译：

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使用大型经验数据集优化天然裂缝性油藏的开发和生产

天然裂缝性油藏是全球石油储量和产量的重要贡献者。现有的裂缝性油藏分类方案不能充分区分某些类型的裂缝性油藏，导致难以理解对油藏性能和采收率的基本控制。对 300 个天然裂缝性储层进行了检查，以定义一种新的分类方案，该方案与压裂类型无关，并描述了根本不同的基质类型、岩石性质、流体储存和流动特征。本研究将裂缝性储层分为三组： 1) 类型 1：以致密基质为特征，其中裂缝和溶液增强的裂缝孔隙度提供储存能力和流体流动通道；2) 类型 2：以大孔基质为主要存储能力，其中裂缝和溶液增强裂缝孔隙度提供基本的流体流动通道；和 3) 类型 3：以微孔基质为特征，可提供所有存储容量，而裂缝仅提供基本的流体流动通道。由固有自然条件（例如岩石和流体特性以及自然驱动机制）赋予的控制与人类控制（例如开发方案和油藏管理实践的选择）之间存在差异。这里提出的分类方案基于天然裂缝性油藏的储层和生产特征，是对现有方案的改进。这种改进允许在类似的裂缝性储层之间进行准确的比较，以及待识别的储层性能的趋势和异常值。此处提供的案例历史证明了这种新分类方案的实际应用以及将其应用于了解天然裂缝性储层时产生的好处。