Numerical Investigation on Propagation Behaviors of a Three-Dimensional Fracture Network Coupled with Microseismicity in Fractured Shale Reservoirs

The formation mechanism and propagation behaviors of a three-dimensional hydraulic fracture network in fractured shale reservoirs remain unclear, especially when the scale of hydraulic fractures is much larger than that of natural fractures. In this study, taking the well XH in the Longmaxi shale reservoir in the Sichuan Basin, China as an example, we develop a fully three-dimensional numerical model for hydraulic fracturing coupled with microseismicity based on the discrete lattice method. We introduce a randomly generated discrete fracture network into the proposed model and explore the formation mechanism of the hydraulic fracture network under the condition that the hydraulic fractures are much larger than natural fractures in scale. Moreover, microseismic events are inversely synthesized in the numerical model, which allows the evolution of the fracture network to be monitored and evaluated quantitatively. In addition, we analyze the effects of injection rate, horizontal stress difference, and fluid viscosity on fracture propagation. Our results show that when the scale of hydraulic fractures is much larger than that of natural fractures, the fracture morphology of “main hydraulic fractures + complex secondary fractures” is mainly formed. We find that a high injection rate can not only create a complex fracture network, but also improve the uniform propagation of multi-cluster fractures and enhance far-field stimulation efficiency. Optimizing the horizontal wellbore intervals with low horizontal stress differences as the sweet spots of hydraulic fracturing is also beneficial to improve the stimulation efficiency. For zones with a large number of natural fractures, it is recommended to use an injection schedule with high viscosity fluid early and low viscosity fluid late to allow the hydraulic fractures to propagate to the far-field to maximize the stimulation effect.

Exploration of Local Wisdom-Based Physics Learning Resources in the COKSACAR Case Study

<em>Research objectives were to (1) Know the exploration of learning resources based on local wisdom; (2) To find out that local wisdom can be used as a learning resource in Viscosity material; (3) How to grow the entrepreneurial spirit with learning resources based on local wisdom. Qualitative descriptive research method with inductive and deductive analysis techniques. Data collection methods used documentation and participatory observation. The results showed that: (1) The form of exploration of learning resources based on local wisdom in the Wonosobo area was carried out with processed food products, namely COKSACAR. COKSACAR is a processed product of Carica fruit combined with chocolate. (2) The process of making COKSACAR as a learning resource for viscosity, namely the basic concepts and factors that affect viscosity in the form of the chocolate dough viscosity, fluid substances, the temperature in chocolate processing, and additives in the chocolate dough. (3) Learning resources based on local wisdom using COKSACAR can grow the entrepreneurial spirit, including (a) Motivation through the promotion of COKSACAR products. (b) Able to cultivate self-confidence, result-oriented, risk-taking, leadership, future-oriented, and able to find original and creative and innovative ideas. Learning resources that utilize the local potential of COKSACAR can foster a spirit of learning and train students' entrepreneurial spirit</em>

Inertia Effects in the Dynamics of Viscous Fingering of Miscible Fluids in Porous Media: Circular Hele-Shaw Cell Configuration

We present a numerical study of viscous fingering occurring during the displacement of a high viscosity fluid by low viscosity fluid in a circular Hele-Shaw cell. This study assumes that the fluids are miscible and considers the effects of inertial forces on fingering morphology, mixing, and displacement efficiency. This study shows that inertia has stabilizing effects on the fingering instability and improves the displacement efficiency at a high log-mobility-viscosity ratio between displacing and displaced fluids. Under certain conditions, inertia slightly reduces the finger-split phenomenon and the mixing between the two fluids.

Fluid Mechanics at the Interface between a Variable Viscosity Fluid Layer and a Variable Permeability Porous Medium

Coupled parallel flow of fluid with pressure-dependent viscosity through an inclined channel underlain by a porous layer of variable permeability and variable thickness is initiated in this work. Conditions at the interface between the channel and the porous layer reflect continuity assumptions of velocity, shear stress, pressure and viscosity. Viscosity is assumed to vary in terms of a continuous pressure function that is valid throughout the channel and the porous layer. Model equations are cast in a form where the pressure as an independent variable and solutions are obtained to illustrate the effects of flow and media parameters on the dynamics behaviour of pressure-dependent viscosity fluid. A permeability and a viscosity adjustable control parameters are introduced to avoid unrealistic values of permeability and viscosity. This work could serve as a model for flow over a mushy zone.