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Using Cohesive Zone Model to Simulate the Hydraulic Fracture Interaction with Natural Fracture in Poro-Viscoelastic Formation

Figure 8. Crack geometry in different fracturing fluid injection rate.

Using Cohesive Zone Model to Simulate the Hydraulic Fracture Interaction with Natural Fracture in Poro-Viscoelastic Formation The numerical procedure for hydraulically driven fracture propagation uses a poro-viscoelasticity theory to describe the fluid diffusion and matrix creep in the solid skeleton, in conjunction with pore-pressure cohesive zone model and ABAQUS was used

Numerical and Experimental Investigations of the Interactions between Hydraulic and Natural Fractures in Shale Formations

Figure 19. Photographs of specimen Y-7-1 after conducting experiments.

Numerical and Experimental Investigations of the Interactions between Hydraulic and Natural Fractures in Shale Formations The inelastic deformation, e.g., stick, slip and separation, of the geologic discontinuities is captured by a special friction joint element called Mohr-Coulomb joint element. The dynamic stress transfer mechanisms between the two fracture systems and the

Cyclic CH4 Injection for Enhanced Oil Recovery in the Eagle Ford Shale Reservoirs

Figure 1. The sketch of CH4 injection process in the fractured horizontal well (CH4 molecules diffuse into different nanopores).

The confined phase behavior was incorporated in the model considering the critical property shifts and capillary pressure. Subsequently, we built a field-scale simulation model of the Eagle Ford shale reservoir. The fluid properties under different pore sizes were evaluated. Finally, a series of studies were conducted to examine the contributions of

The effect of interbedding on shale reservoir properties Kimmeridge Clay Formation

Figure 1. Structural elements of the North Sea showing the framework of the Viking Graben (modified from Dominguez, 2007) with inset of UK Quadrant 16 showing the location of wells studied (modified from DECC, 2013).

Abstract North Sea oil is overwhelmingly generated in shales of the Upper Jurassic – basal Cretaceous Kimmeridge Clay Formation. Once generated, the oil is expelled and ultimately migrates to accumulate in sandstone or carbonate reservoirs. The source rock shales, however, still contain the portion of the oil that was not expelled.

Microstructural imaging and characterization of oil shale before and after pyrolysis

Fig. 13. (A) Porosity of 10 oil shale samples after pyrolysis at 500 °C, (B) – (D). 2-D gray scale images for organic-rich, organic-mixed and organic-lean regions respectively. (E) – (G) 3-D rendered volumes with the pore space visualized in blue.

Abstract The microstructural evaluation of oil shale is challenging which demands the use of several complementary methods. In particular, an improved insight into the pore network structure and connectivity before, during, and after oil shale pyrolysis is critical to understanding hydrocarbon flow behavior and enhancing recovery. In this experimental study, bulk

Mechanism of multi-stage sand filling stimulation in horizontal shale gas well development

Fig. 1. Body-centered cubic and face-centered cubic models of equant spheres.

With consideration to the limitations in the implementation of the mechanical staging technique with bridge plug for shale gas development in the Sichuan–Chongqing area, the technique of multi-stage sand filling stimulation in horizontal wells was proposed to solve the above-mentioned problems. By filling sands in fractures, it is possible to

Strengthening shale wellbore with silica nanoparticles drilling fluid

Fig. 7. SEM images of shale surface (a) nanoparticles within shale and (b) aggregate of nanoparticles plugging a pore throat.

Higher concentration of nanoparticles can induce better plugging effect. However, for the OBDFs, nanoparticles did not show these positive effects like the nano WBDFs, even leaded to some negative effects such as higher filtration and larger Young's-modulus reduction. The main reasons are that the silica nanoparticles can easily disperse in

Deformation mechanism of horizontal shale gas well production casing and its engineering solution: A case study on the Huangjinba Block of the Zhaotong National Shale Gas Demonstration Zone

Fig. 5. Three-dimensional imaging interpretation of multiple bending deformation of casing in Well H1-2.

It is shown that severe casing deformation tends to occur where structural fractures are developed. Besides, casing deformation is mainly in the form of “S”-shape bending vertically. The severely deformed casing is also characterized by obviously transverse shear deformation caused by the high-angle sliding compression of rocks. Therefore, some suggestions

Geological characteristics, main challenges and future prospect of shale gas

Fig. 2. Distribution diagram for onshore shale gas fields in the US [3].

It includes non-marine shale gas potential, core technology and equipment for resource deep than 3500 m, complex surface “factory mode” production, human geography and other non-technical factors. (4) Process economic evaluation under the conditions of government financial subsidies. China's shale gas project FIRR is about 8.0%–9.0%. Considering the global shale

Three-dimensional characterization of micro-fractures in shale reservoir rocks

Fractures are crucial for unconventional hydrocarbon exploitation, but it is difficult to accurately observe the 3D spatial distribution characteristics of fractures. Microtomography (micro-CT) technology makes it possible to observe the 3D structures of fractures at micro-scale.

Therefore, the independently-developed CTSTA program is adopted to quantitatively describe the micro-fractures inside rock core, including fracture dimension, extension direction and extension scale. Meanwhile, this study summarizes the classification characteristics of fractures and their anisotropy. On this basis, the fractal dimensions of fractures can also be extracted. Previous studies show that