a b s t r a c tShale formations consist of numerous nanoscale pores within a range of 2 nme50 nm; the shale gas flow within this size range under typical shale reservoir pressure and temperature will fall into the slip flow or the transitional flow regime 0.001 < K n < 10. Besides nano-pores in shale, there exist a number of mesoscopic and macroscopic pores with size larger than 50 nm, and many micrometer fractures. Natural gas, mainly methane, flows through nanoscale pores, mesoscale, and macroscopic pores or fractures during the production period. Gas slippage described by the Klinkenberg effect reduces viscous drag near the pore walls and influences permeability. In shale, the majority of gas molecules are adsorbed in kerogen that is considered to be organic source rocks. Within nano-pores and meso-pores, Darcy's law cannot effectively describe this type of transport phenomena due to its continuum assumption. Alternatively, the kinetic-based lattice Boltzmann method (LBM) becomes a strong candidate for simulating an organic-rich shale reservoir that contains a large number of nano-pores. In this paper, we present a multiple-relaxation-time (generalized) LBM, which is considered to be one of the most efficient LBM models. For gas flow in a confined system, its molecular mean free path is corrected depending on the size of the confined system and the distance of the gas molecules from the pore walls. Gas slippage on pore walls is captured with a combined bounce-back specular reflection boundary condition. In addition, adsorbed gas in shale has a significant influence on gas transport in shale gas production. Here, we propose to incorporate inter-molecular and adsorptive forces into the generalized LBM algorithm to capture gas adsorptions in organic nano-pores. Therefore, this approach is able to simulate gas flow with adsorption effect. Many factors are believed to control the flow mechanisms in these types of pores, including the pore size distribution, the specific surface area, and the adsorptive feature of the pore walls. The simulation results agree well with the existing data for high Knudsen flows between 2D parallel plates. Accounting for the adsorption and slippage effects, flow phenomena are investigated by varying different controlling factors in both simple and complex structures. The permeability of methane is also determined for complex porous geometries.

Although natural gas is widely produced from shale, the mechanisms of natural gas transport in shale matrices remain poorly understood due to the complex chemical compounds of the matrices and the nanoscale pore size distribution. Using molecular simulations, we investigate natural gas transport and storage in nanopore networks. Carbonbased 3-D pore networks are generated from 2-D scanning electron microscopy (SEM) images of a shale rock using the Markov Chain Monte Carlo simulation method. We employ a grand canonical Monte Carlo (GCMC) simulation to calculate adsorption isotherms of natural gas in carbon-based 3-D pore networks, which can be fit by a Langmuir isotherm model. To investigate gas transport in the same structures, we insert an external driving force into non-equilibrium molecular dynamics (NEMD) simulations and find that Knudsen diffusion is the dominant transport mechanism in the pore networks. Although porosity and pore connectivity affect the natural gas diffusion in the pore networks, we typically observe a linear relationship between average molar flow rate through a cross-sectional area and the external driving force.

The rise of social media in the enterprise has enabled new ways for employees to speak up and communicate openly with colleagues. This rich textual data can potentially be mined to better understand the opinions and sentiment of employees for the benefit of the organization. In this paper, we introduce Enterprise Social Pulse (ESP) -a tool designed to support analysts whose job involves understanding employee chatter. ESP aggregates and analyzes data from internal and external social media sources while respecting employee privacy. It surfaces the data through a user interface that supports organic results and keyword search, data segmentation and filtering, and several analytics and visualization features. An evaluation of ESP was conducted with 19 Human Resources professionals. Results from a survey and interviews with participants revealed the value and willingness to use ESP, but also surfaced challenges around deploying an employee social media listening solution in an organization.

In shale formations, natural gas flows either through nano-scale pores or fractures during production period. Darcy's law cannot effectively describe such transport phenomena due to its continuum assumption. Alternatively, kinetic-based lattice Boltzmann method (LBM) becomes a strong candidate of simulating organic-rich shale reservoir that contains a large amount of nano-scale pores. Among various LBM models, multiple-Relaxation-Time (generalized) LBM is considered as one of the most efficient models regarding its theories, selections of parameters, and numerical stability. For gas flow in a confined system, its molecular mean free path depends on not only the size of the confined system, but also the distance of gas molecules from solid walls. A large amount of natural gas is believed to be stored in extremely small organic pores, and adsorption in shale has a significant influence for gas transport in production. In this paper, we incorporated adsorption into generalized LBM model in order to capture the natural gas flow in organic nano-pores. Many factors are believed to control the flow mechanism in such pores, such as the size of organic pores, specific surface area, adsorptive strength, and so on. Generalized LBM results shows a great agreement with available data for high Knudsen flows between twodimensional parallel plates. Accounted the effect of adsorption, flow phenomena are investigated by varying different controlling factors in both simple and complex structures.

No abstract