Production prediction for fracture-vug carbonate reservoirs using electric imaging logging data

Xie, Fang; Zhang, Chengsen; Liu, Ruilin; Xiao, Chengwen

doi:10.1016/s1876-3804(18)30041-7

Cited by 13 publications

(3 citation statements)

References 13 publications

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“…Building upon previous models of singular inclined fractures and inclined slab-like fractures [16,17], we developed three types of fractured formation models according to the geometric relationship between the fracture orientation, borehole radius, and detection depth of the deep lateral resistivity log of the dual laterolog tool: (i) The intersection of the fracture plane with the bottom plane of the electrode column is outside the radial detection depth of the electrode (Figure 2a). The angle between the fracture plane and the bottom plane of the electrode column is the fracture inclination angle θ, in degrees; the vertical distance between the two walls of the fracture represents the fracture width w, in µm; the borehole radius is denoted as r, in m; the radial detection depth of the deep laterolog is r 1 , in m; and the height of the cylindrical main current of the deep laterolog is H, in m, which is typically 0.74 m. In all models, the effective conductive medium is analogous to that of a vuggy reservoir.…”

Section: Fractured Reservoirsmentioning

confidence: 99%

“…Due to their intense heterogeneity, carbonate reservoirs exhibit features of secondary porosity, including dissolution-enhanced Processes 2024, 12, 43 2 of 21 fractures and vugs, making their microscopic pore structures exceedingly complex [6,14,15]. These complex fractured-cavernous structures in carbonate reservoirs result in inexplicable resistivity response patterns [16][17][18], such as numerous layers with anomalously high resistivity, dense layers with low resistivity, and water-bearing layers with high resistivity. Hence, examining the effects of these fractured-cavernous structures on the resistivity of geofluid-saturated rocks is important to deepen the understanding of their resistivity response patterns, identify their fluid properties, and evaluate their fluid saturation state during the exploration and development of complex fractured-cavernous carbonate hydrocarbon reservoirs.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical Simulation of the Resistivity and Fractured–Cavernous Structures of Carbonate Reservoirs

Zhang,

Gao,

Gao

et al. 2023

Processes

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Recently, theoretical modeling based on rock physics has emerged as a pivotal approach to studying the resistivity of complex fractured–cavernous microstructures. In this work, to study the effects of fractured–cavernous structures on carbonate reservoir resistivity, electrical conductivity models were developed based on the effective medium theory and Ohm’s Law, and theoretical simulations were performed to examine how the porosity and resistivity of the rock matrix, the formation water resistivity, and the parameters of the fractured–cavernous microstructure affect the resistivity of rocks saturated with petroleum or water. Furthermore, the modeling results revealed the specific relationships between these factors in petroleum-saturated and water-saturated rocks. For vuggy reservoirs, a significant negative correlation between throat diameter and resistivity was revealed when variations in the rock matrix and formation water resistivity were negligible. Furthermore, the pore shape—especially the extension of pores in the direction of the current—severely reduced the resistivity of petroleum-saturated rocks. For fractured reservoirs, the porosity and resistivity of the rock matrix were the primary factors affecting resistivity, with the fracture inclination angle and width also exhibiting pronounced effects on the resistivity of water-saturated rocks. The rock cementation exponent was much smaller when the matrix pores were interconnected through fractures than when they were interconnected through throats. The findings reveal that the effects of the structural parameters of fractured–cavernous carbonate reservoirs on reservoir resistivity differ between petroleum-saturated and water-saturated rocks. The conventional Archie’s equation is insufficient for evaluating fluid saturation in carbonate reservoirs. A saturation evaluation model with a variable rock cementation exponent tailored to the specific reservoir type should thus be developed.

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Section: Fractured Reservoirsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Theoretical Simulation of the Resistivity and Fractured–Cavernous Structures of Carbonate Reservoirs

Zhang,

Gao,

Gao

et al. 2023

Processes

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“…When the pores within a cave are relatively large and exhibit good connectivity, the flow inside the cave can be considered laminar flow. Furthermore, the laminar flow of incompressible viscous fluids in narrow conduits can be equivalent to Hagen-Poiseuille flow (Xie et al, 2018;Lin et al, 2021). Therefore, the fluid flow within the cave can be approximated as Hagen-Poiseuille flow, enabling the coupling of flow between different media.…”

Section: Introductionmentioning

confidence: 99%

Numerical well test model of oil-water two-phase flow in fractured and vuggy carbonate reservoir

Xu,

Yin,

Zhang

et al. 2023

Adv. Geo-Energy Res.

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Fractured and vuggy carbonate reservoirs present a complex storage space with irregularly distributed fractures and caves. Furthermore, these reservoirs typically feature the presence of a substantial bottom aquifer, further complicating the fluid flow dynamics. At present, most well test models for this reservoir are based on discrete media primarily address single-phase flow scenarios, typically considering caves as equipotential bodies. This approach cannot accurately represent the complexities of such reservoirs. In this paper, a three-dimensional numerical well test model for two-phase oil-water flow within fractured and vuggy carbonate reservoirs is introduced. Randomly generated natural fractures are embedded within the reservoir, and the Hagen-Poiseuille law is utilized to describe fluid flow within cave spaces, effectively coupling flow interactions across fractures, caves and the porous rock matrix. The computational domain is discretized by a perpendicular bisection grid, and the finite volume method is used to solve the model, allowing for the calculation of the pressure and saturation fields at each time step. Subsequently, well test type curves are constructed and analyzed, flow regimes are segmented, and sensitivity analysis of model parameters is conducted. The pressure buildup data from well A are interpreted, and the results demonstrate a remarkable agreement between the well test curve and actual data, confirming the capability of the model to capture reservoir characteristics and complex fluid flow phenomena. The findings lay the foundation for the development of numerical well test models tailored to fractured and vuggy carbonate reservoirs.

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Fault-karst systems in the deep Ordovician carbonate reservoirs in the Yingshan Formation of Tahe Oilfield Tarim Basin, China

Li,

Wang,

et al. 2023

Geoenergy Science and Engineering

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Production prediction for fracture-vug carbonate reservoirs using electric imaging logging data

Cited by 13 publications

References 13 publications

Theoretical Simulation of the Resistivity and Fractured–Cavernous Structures of Carbonate Reservoirs

Theoretical Simulation of the Resistivity and Fractured–Cavernous Structures of Carbonate Reservoirs

Numerical well test model of oil-water two-phase flow in fractured and vuggy carbonate reservoir

Fault-karst systems in the deep Ordovician carbonate reservoirs in the Yingshan Formation of Tahe Oilfield Tarim Basin, China

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