A Methodology for Simulation of Vuggy and Fractured Reservoirs

Kossack, C.A.; Gurpinar, Omer

doi:10.2118/66366-ms

Cited by 31 publications

(5 citation statements)

References 5 publications

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“…However, the multi-porosity continuum models and radial composite model are often applied to well test interpretation in the early stage of oilfield development [23][24][25][26][27][28][29][30][31][32]. Oilfield engineers quickly found huge derivation between the interpretation results and actual oilfield conditions.…”

Section: Introductionmentioning

confidence: 99%

Parameters evaluation of fault-karst carbonate reservoirs with vertical beads-on-string structure based on bottom-hole pressure: Case studies in Shunbei Oilfield, Tarim Basin of Northwestern China

Cao

Cheng

Chen³

et al. 2021

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Tarim Basin newly discovered the fault-karst carbonate reservoirs, which are formed by the large-scale tectonic fault activities and multiple-stage karstification. Four kinds of mediums coexist in the reservoirs, including the large cave, vug, tectonic fracture and matrix. The tectonic fractures interconnect with large caves in series to form the vertical beads-on-string structure, which is the most common connection pattern in reservoirs. To provide a well test method for evaluating this type of structure, this work firstly presents a multi-fracture-region multi-cave-region series connection physical model by simplifying vertical beads-on-string structure. We consider four kinds of mediums in the proposed physical model, including large caves, small vugs, high-angle tectonic fracture and rock matrix. The fracture regions mainly contain fracture, vug and matrix mediums. The cave regions contain cave medium. The corresponding mathematical model is also developed, in which the flow in fracture regions obeys the Darcy’s law, while the flow in cave regions is assumed to obey free flow. Furthermore, the gravity is taken into account because the flow is along the vertical direction. Then the typical flow regimes are analyzed and sensitivity analysis is conducted on crucial parameters. Results indicate that (a) the typical feature of vertical beads-on-string structure on type curves is that the cave storage regimes and linear flow regimes alternately appear; (b) the type curves will exhibit the cave storage regimes with unit-slope pressure derivative for the existence of large caves, which is different from the inter-porosity flow regimes for the existence of the vugs (slope ≠ 1); (c) the gravity effect could lead to unit-slope pressure and pressure derivative curves, which can be regarded as closed boundary in a peculiar sense; (d) gravity effect is difficult to be observed from well test curves with about 2-weeks test duration in real application. Finally, two cases from Shunbei Oilfield are interpreted to illustrate the practicability and feasibility of proposed method.

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Section: Introductionmentioning

confidence: 99%

Parameters evaluation of fault-karst carbonate reservoirs with vertical beads-on-string structure based on bottom-hole pressure: Case studies in Shunbei Oilfield, Tarim Basin of Northwestern China

Cao

Cheng

Chen³

et al. 2021

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

View full text Add to dashboard Cite

show abstract

“…Therefore, they have generated a great scientific interests (Camacho Velazquez et al 2005;Kang et al 2006;Kossack and Gurpinar 2001;Liu et al 2003;Peng et al 2009;Popov et al 2007;Qin et al 2010;Wu et al 2007). However, modeling such reservoirs is a challenging task due to their complexity.…”

Section: Introductionmentioning

confidence: 99%

Discrete Fracture-Vug Network Modeling in Naturally Fractured Vuggy Reservoirs Using Multiple-Point Geostatistics: A Micro-Scale Case

Fadlelmula

Fraim

et al. 2015

SPE Annual Technical Conference and Exhibition

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Most of the world's massive fields produce from naturally fractured vuggy carbonate reservoirs. However, modeling such reservoirs is a challenging task due to the co-existence of porous and free-flow domains over a wide range of scales. Realistic characterization of fractured vuggy reservoirs requires preservation of the geological structure and reproduction of patterns. In this study, we model a discrete fracture-vug network using microtomography and multiple-point geostatistics (MPG) modeling technique. For this purpose, one micro-CT scan image of a real core is used to generate a micro-scale geological model (the reference model and the first training image) having three structures; matrix, fractures, and vugs.The structures in the reference model are also separated into matrix-fracture and matrix-vug to construct two other training images. The three training images are then used in MPG to generate multiple equiprobable models that mimic the original networks of the fractures and vugs. The models created using matrix-fracture and matrix-vug training images are combined into fracture-vug-matrix models by superimposing the fracture networks from the matrix-fracture models on their corresponding matrix-vug models. The spatial continuity, patterns reproduction, and flow performance of the generated models are compared with those of the reference model. The results show that, although the fracture patterns are not well reproduced, all the generated realizations preserved the structures and reproduced the spatial continuity of the reference model. In addition, the study revealed that the flow curves of the models generated with the introduced combined MPG method bracket better with the curve of the reference model than those of the direct MPG method. These results lay the foundation for future application of the presented method to field-scale modeling of naturally fractured vuggy reservoirs.

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“…As we know, there are the current largest fractured-vuggy reservoirs in the Tarim Basin Ordovician carbonate reservoir in china, such reservoir with strong heterogeneity, spatial structure of complex characteristics, and the cave is the important reservoir space [1][2][3][4][5]. Currently, those reservoirs mainly depend on the elastic energy of fluid and cavity to mining, in the absence of sufficient reservoir of energy, water injection will be conducted for adding formation energy.…”

Section: Introductionmentioning

confidence: 99%

Elastic Exploring Law Analysis of the Deep Vuggy Reservoir

Chang

Zhang

Xiong

et al. 2011

AMM

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The deep cave is an important storage space in the fractured-vuggy reservoir in the Tahe oilfield, with large differences in spatial structure and the complex relationship between oil and water features, so far, mainly in elastic energy as the driving force for mining; this paper, base on the elasticity theory, analyses mining characteristics of the three fractured-vuggy model, and found that the bottom hole pressure has a certain relationship with the fracture and cave properties, the bottom hole pressure equation was established, and verified the bottom hole pressure variation of three fractured-vuggy mode by physical simulation, and analyzed the relationship between cumulative production and accumulation of pressure drop curves, the results showed that: showed a single index of changes in bottom hole pressure for the single cave mode and single-fractured-cave mode, and the cumulative production and cumulative pressure drop curve is linear, the bottom hole pressure showed double-index change for the cave-fractured-cave model, and the cumulative production and accumulation of pressure drop curves have a bend segment, this research provide a basis for the development in the deep vuggy reservoir .

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A Methodology for Simulation of Vuggy and Fractured Reservoirs

Cited by 31 publications

References 5 publications

Parameters evaluation of fault-karst carbonate reservoirs with vertical beads-on-string structure based on bottom-hole pressure: Case studies in Shunbei Oilfield, Tarim Basin of Northwestern China

Parameters evaluation of fault-karst carbonate reservoirs with vertical beads-on-string structure based on bottom-hole pressure: Case studies in Shunbei Oilfield, Tarim Basin of Northwestern China

Discrete Fracture-Vug Network Modeling in Naturally Fractured Vuggy Reservoirs Using Multiple-Point Geostatistics: A Micro-Scale Case

Elastic Exploring Law Analysis of the Deep Vuggy Reservoir

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