Browsing by Author "Huang, Xuemin"

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    Application of Dilation-Recompaction Model in Hydraulic Fracturing Simulation
    (2015-04-30) Huang, Xuemin; Gates, Ian; Chen, Shengnan
    Production of unconventional oil and gas resources has played a significant role on the global energy supply, of which tight oil and gas reservoirs are drawing greater focus. The key enabler behind tight oil and gas production has been multi-stage hydraulic fracturing along extended reach horizontal wells. Despite many advances in multistage fracturing, it still remains unclear how to model the hydraulic fracturing process to provide the basis to optimize and predict the properties of fracture networks and associated enhancement of fluid production. This is especially difficult since it is not possible to directly image the fracture network since the length scales of the network can be relatively small. In typical reservoir simulation practice, the conventional way to represent the hydraulic fracture is to place transverse plane around the horizontal well – this means that the user has prescribed the orientation and length scale of the fracture before the simulation has started. In the research documented here, we explore a dynamic fracturing approach that uses a dilation-recompaction model in a reservoir simulator to model hydraulic fracturing. The key strength of the approach is that the geometry and length scale of the fracture is not prescribed a priori. This means that the model can be relatively easily constructed and matched to field data. The results of the simulation show that dilation-recompaction model is capable of modeling the hydraulic fracturing process prior to the flow-back and production. The oil, gas, and water rates of the model are well matched to the field data and the extent of the fractured zone predicted by the model is reasonable. A sensitivity analysis using the history-matched model reveals that the design of hydraulic fracturing operation suggests that a larger number of stages and fracture fluid volume injected will raise oil and gas rates, but it remains unclear if the incremental oil and gas will provide enough revenues to offset the additional costs from increases of stages and fluid injection volume.
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    Effect of Roughness on Wetting of Solids
    (2021-04-26) Huang, Xuemin; Gates, Ian; Hejazi, Hossein; Lu, Qingye
    The wetting of rough surfaces and the three-phase contact line are complex and vary according to the dimensions of the roughness and its spatial heterogeneity. The results documented in this thesis show that the apparent contact angle varies around the periphery of the water droplet due to the roughness of the surface on the first contact. Also, repeated wetting of the droplet on the surface reveals that the apparent contact angle changes due to residual liquid remaining on the rough surface. The wetting of water droplets is even more complex for curved rough surfaces. For these surfaces, at the three-phase contact line, the line tension contributes to the force balance. In this research, experiments reveal the effect of the roughness and curvature of a solid surface on the apparent contact angle as well as the line tension: the greater the roughness and the curvature of the solid, the larger is the line tension. Evaporation of sessile water droplets on solid surfaces has drawn much attention. Classic models do not describe evaporation near the three-phase contact line of rough surfaces. Here, we describe a new model for evaporation of sessile droplets on rough solid surfaces and compare the results to experimental results. The results suggest that the evaporation rate is larger on rougher surfaces. Electrokinetic phenomena which are founded on the physical mechanisms of streaming potential, zeta potential, electrical double layer (EDL) have an impact on rock wettability. If an electrolyte flows through porous rock, given the EDL and charge transport, potentially a current could occur in the system. In other words, given the existing salt concentration in reservoir water, there is potential that the moving liquid during production or water flooding or under natural flow could generate a current. Here, we report on experiments to explore the idea of the current generation from the flow of electrolytes through porous sandstone.