Geomechanical implications of dissolution of mineralized natural fractures in shale formations

Shovkun, Igor; Espinoza, D. Nicolas

doi:10.1016/j.petrol.2017.10.043

Cited by 15 publications

(5 citation statements)

References 21 publications

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“…[22,23] In summary, shale gas reservoirs possess multi-scale porous systems containing macro-scale hydraulic fractures, micro-scale natural fractures and various pores ranging from nanometres to micrometres. [24][25][26][27] As illustrated in Figure 2, fluids flow through the multi-scale space during the production process.…”

Section: Introductionmentioning

confidence: 99%

A comprehensive review on the flow behaviour in shale gas reservoirs: Multi‐scale, multi‐phase, and multi‐physics

Feng

Chen

et al. 2022

Can J Chem Eng

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An accurate description of fluid flow is critical for the prediction of the productivity of shale gas reservoirs. In this paper, we present the current advances and a systematic summary on the fluid flow in shale gas reservoirs. First, shale pore structures, consisting of organic pores and inorganic pores ranging from nanoscale to micro-scale, and reservoir fluids, including free gas, absorbed gas, and water, are systematically presented. Thereafter, multi-physics flow phenomena motivated by scale effects, such as continuum flow, slip flow, transition flow, free molecular flow, and surface diffusion for gas, as well as the effective viscosity and slip boundary condition for water, are carefully summarized. Meanwhile, these flow mechanisms are discussed with molecular dynamics (MD) simulations and theoretical analysis. Subsequently, on the basis of upscaling approaches, including capillary bundle models, the lattice Boltzmann method (LBM), and pore network models (PNMs), fluid flow through heterogeneous shale matrix is reviewed and the influences of scale effects and pore structures are clarified. Additionally, shale gas well performance is discussed by combining the multiple transport mechanisms and a fracturing-shut-in-flowback-production process. Our review concluded that the fluid flow behaviour in shale gas reservoirs is a complex multi-scale process accompanied by multi-physical phenomena and multi-fluid distributions. Keeping this in mind is helpful for predicting the shale gas production and recoverable gas resources. We expect this study can not only help by providing a better understanding of the fluid flow in shale reservoirs but also provide significant implications to address other multiphase flow processes.

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Section: Introductionmentioning

confidence: 99%

A comprehensive review on the flow behaviour in shale gas reservoirs: Multi‐scale, multi‐phase, and multi‐physics

Feng

Chen

et al. 2022

Can J Chem Eng

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“…It can be divided into fractured shale oil, brittle interlayered shale oil, and matrix shale oil [2,5]. Fractures of various scales are regarded as primary storage spaces in fractured shale-oil reservoirs [6][7][8][9]. Fractures are also the key factor that determine whether shale oil can be enriched.…”

Section: Introductionmentioning

confidence: 99%

Characteristics and Controlling Factors of Natural Fractures in Continental Tight-Oil Shale Reservoir

Gong

et al. 2022

Minerals

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Natural fracture growth plays an important role in shale-oil enrichment. Systematically investigating fracture features and their controlling factors in shale-oil reservoirs is essential for accurately predicting fracture distribution. The controlling factors of fracture distribution in the continental shale of the Qingshankou Formation in the Songliao Basin, China, were systematically analyzed based on the quantitative fracture characterization of outcrops and cores. Strata-confined fractures, throughgoing fractures, bedding-parallel fractures, and stylolites can be observed in the Qingshankou shale reservoir in the study area. Fracture distribution is not only controlled by internal factors, e.g., mineral composition, mechanical stratigraphy, and lithofacies, but also by external factors, e.g., faults and abnormally high pressure readings. Mineral composition is the primary factor governing fracture development, and it not only controls fracture abundance, but it also affects fracture filling and effectiveness. Mechanical stratigraphy determines the spatial morphology and developmental pattern of a fracture. Fractures are well-developed in brittle strata, with fracture spacing being proportional to bed thickness. Lithofacies can determine fracture development by controlling the variation of mineral composition, rock structure, bed thickness, etc. Stress concentration is commonly high at fault tips, intersections, and overlaps, where fracture density is high and has good connectivity. The existence of abnormally high pressure reduces effective stress, promoting shear fracture development. Tensile overpressure fractures can also be generated under small levels of differential stress.

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“…Different scales of natural fractures are developed in shale oil reservoirs [1][2][3][4][5][6]. These natural fractures are effective storage spaces and main seepage channels for shale oil reservoirs [7][8][9][10][11]. Natural fractures not only control the migration, accumulation, preservation, and single well productivity of shale oil, but also affect the fracturing measures and production results [12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Quantitative Prediction of Natural Fractures in Shale Oil Reservoirs

et al. 2021

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Natural fractures are the key factors controlling the enrichment of shale oil. It is of great significance to clarify the distribution of natural fractures to guide the selection of sweet spots for shale oil. Taking the Qing-1 Member shale oil reservoir in the northern Songliao Basin, China as an example, a new method considering the factors affecting fracture distribution was proposed to quantitatively predict the structural fractures. And the effect of natural fractures on shale oil enrichment was discussed. Firstly, the types and characteristics of fractures in shale oil reservoirs are characterized by using core and outcrop data. Combined with the experimental analysis, the influences of fault, mechanical stratigraphy, mineral composition and content, TOC, and overpressure on fracture intensity were clarified. Then, the number and density of fractures are quantitatively predicted according to the power-law distribution of fault length. Next, geomechanical simulation and fracture prediction were carried out on the model which was established with comprehensive consideration of the influencing factors of fracture distribution. Finally, the fracture distribution is evaluated comprehensively based on above prediction. The prediction results in this work are consistent with the core measurements.

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Geomechanical implications of dissolution of mineralized natural fractures in shale formations

Cited by 15 publications

References 21 publications

A comprehensive review on the flow behaviour in shale gas reservoirs: Multi‐scale, multi‐phase, and multi‐physics

A comprehensive review on the flow behaviour in shale gas reservoirs: Multi‐scale, multi‐phase, and multi‐physics

Characteristics and Controlling Factors of Natural Fractures in Continental Tight-Oil Shale Reservoir

Quantitative Prediction of Natural Fractures in Shale Oil Reservoirs

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