Rock Evaluation and Wellbore Stability0
Pore structure characterization of Chang-7 tight sandstone using MICP combined with N2GA techniques and its geological control factors

Pore structure characterization of Chang-7 tight sandstone using MICP combined with N2GA techniques and its geological control factors
Flow Mechanics
Shale Gas Productivity Predicting Model and Analysis of Influence Factor

Shale Gas Productivity Predicting Model and Analysis of Influence Factor
Others
Analysis of bacterial diversity in two oil blocks from two low-permeability reservoirs with high salinities

Analysis of bacterial diversity in two oil blocks from two low-permeability reservoirs with high salinities
Rock Evaluation and Wellbore Stability
Real-time detection of dielectric in unconventional oil-gas reservoir rocks supported by the oblique-incidence reflectivity difference

Real-time detection of dielectric anisotropy or isotropy in unconventional oil-gas reservoir rocks supported by the oblique-incidence reflectivity difference technique
Rock Evaluation and Wellbore Stability0
Wellbore Stability in Oil and Gas Drilling with Chemical Mechanical Coupling

Wellbore Stability in Oil and Gas Drilling with Chemical-Mechanical Coupling
Adsorption
Investigation of methane adsorption on chlorite by grand canonical Monte Carlos Simulations

Investigation of methane adsorption on chlorite by grand canonical Monte Carlo simulations
Rock Evaluation and Wellbore Stability
Analysis on Rock Properties Based on Exploration of Hole Wall’s

Analysis on Rock Properties Based on Exploration of Hole Wall’s Stability
Reservoir Simulation
Productivity Model for Shale Gas Reservoir with Comprehensive Consideration of Multi-mechanisms

Productivity Model for Shale Gas Reservoir with Comprehensive Consideration of Multi-mechanisms
Actual Production0
U.S. Dry Shale Gas Production. Antrim, Bakken, Woodford, Barnett, Fayetteville, Eagle Ford, Haynesville, Marcellus, Utica, Permian, Emanuel Martin.

U.S. Dry Shale Gas Production 2017
Flow Mechanics
A mathematical model of multistage fractured horizontal well (MsFHW) considering stimulated reservoir volume (SRV) was presented for tight oil reservoirs. Both inner and outer regions were assumed as single porosity media but had different formation parameters. Laplace transformation method, point source function integration method, superposition principle, Stehfest numerical algorithm, and Duhamel’s theorem were used comprehensively to obtain the semianalytical solution.

Rate Transient Analysis for Multistage Fractured Horizontal Well in Tight Oil Reservoirs considering Stimulated Reservoir Volume
Rock Evaluation and Wellbore Stability
Unconventional resources such as tight, fractured and hybrid shale gas and oil plays as well as oil or kerogen shale systems, are considered exploitable self-contained source and reservoir rocks.Herein, we introduce a new “ready to use” method of analysis and interpretation for the Rock-Eval 6 device for better assessment of free or sorbed hydrocarbons in unconventional shale plays.

New Rock-Eval Method for Characterization of Unconventional Shale Resource Systems
Rock Evaluation and Wellbore Stability
We develop a general solution for merging multiscale categorical spatial data into a single dataset using stochastic reconstructions with rescaled correlation functions. The versatility of the method is demonstrated by merging three images of shale rock representing macro, micro and nanoscale spatial information on mineral, organic matter and porosity distribution. Merging multiscale images of shale rock is pivotal to quantify more reliably petrophysical properties needed for production optimization and environmental impacts minimization.

Universal Stochastic Multiscale Image Fusion: An Example Application for Shale Rock
Others0
Understanding mechanisms of oil mobilization of tight matrix during CO2 injection is crucial for CO2 enhanced oil recovery (EOR) and sequestration engineering design. In this study exposure behavior between CO2 and tight rock of the Ordos Basin has been studied experimentally by using nuclear magnetic resonance transverse relaxation time (NMR T2) spectrum and magnetic resonance imaging (MRI) under the reservoir pressure and temperature.

Measurement and Visualization of Tight Rock Exposed to CO2 Using NMR Relaxometry and MRI
Others
Logging Evaluation Method. Unconventional oil and gas resources, especially shale gas resources have great potential for exploration and development in China. In Shale gas exploration and development process, reservoir pore pressure is a very important parameter, and the pore pressure prediction can improve the appraisal accuracy of project dessert. This paper analyzes several formation pore pressure calculation methods based on logging data, and optimized the “Equivalent depth method”.

Logging Evaluation Method for Pore Pressure of Shale Gas Reservoirs— Taking Fuling area, Sichuan Basin as an example
Hydrulic Fracture
Hydraulic fracturing combined with horizontal drilling has been the technology that makes it possible to economically produce natural gas from unconventional shale gas or tight gas reservoirs. Hydraulic fracturing operations, in particular, multistage fracturing treatments along with horizontal wells in unconventional formations create complex fracture geometries or networks, which are difficult to characterize. The traditional analysis using a single vertical or horizontal fracture concept may be no longer applicable.

Characterizing hydraulic fractures in shale gas reservoirs using transient pressure tests
Rock Evaluation and Wellbore Stability
We construct a rock physics model for organic-rich shales to quantify the effect of kerogen content and kerogen porosity using the Kuster and Toksöz theory and the self-consistent approximation method. Rock physics modeling results show that with the increase of kerogen content and kerogen-related porosity, the velocity and density of shales decrease, and the effect of kerogen porosity becomes more obvious only for higher kerogen content.

A rock physics model for the characterization of organic-rich shale from elastic properties
Rock Evaluation and Wellbore Stability0
Tight oil has become the focus in exploration and development of unconventional oil in the world, especially in North America and China. In North America, there has been intensive exploration for tight oil in marine. In China, commercial exploration for tight oil in continental sediments is now steadily underway. With the discovery of China’s first tight oil field—Xin’anbian Oilfield in the Ordos Basin, tight oil has been integrated officially into the category for reserves evaluation.

Geological characteristics and ‘‘sweet area’’ evaluation for tight oil
Flow Mechanics
The irregular morphology of single rock fracture significantly influences subsurface fluid flow and gives rise to a complex and unsteady flow state that typically cannot be appropriately described using simple laws. Yet the fluid flow in rough fractures of underground rock is poorly understood. Here we present a numerical method and experimental measurements to probe the effect of fracture roughness on the properties of fluid flow in fractured rock. We develop a series of fracture models with various degrees of roughness characterized by fractal dimensions that are based on the Weierstrass– Mandelbrot fractal function. The Lattice Boltzmann Method (LBM), a discrete numerical algorithm, is employed for characterizing the complex unsteady non-Darcy flow through the single rough fractures and validated by experimental observations under the same conditions.

Fractal model and Lattice Boltzmann Method for Characterization of Non-Darcy Flow in Rough Fractures
Reservoir Simulation
Also at the well location, although the well may penetrate a productive shale, but in the same interval, away from the well location there might be non-productive shale sections. In other words, in unconventional shale reservoirs, productive shale zones and non-productive shale sections have randomly been distributed as illustrated in Fig. 3.

Well test, rate transient analysis and reservoir simulation for characterizing multi-fractured unconventional oil and gas reservoirs
Others
Managing the wastewater discharged from oil and shale gas fields is a big challenge, because this kind of wastewater is normally polluted by high contents of both oils and salts. Conventional pressure-driven membranes experience little success for treating this wastewater because of either severe membrane fouling or incapability of desalination. In this study, we designed a new nanocomposite forward osmosis (FO) membrane for accomplishing simultaneous oil/water separation and desalination. This nanocomposite FO membrane is composed of an oil-repelling and salt-rejecting hydrogel selective layer on top of a graphene oxide (GO) nanosheets infused polymeric support layer.

A new nanocomposite forward osmosis membrane custom-designed for treating shale gas wastewater
Hydrulic Fracture0
We implement proppant transport in a three-dimensional hydraulic fracturing simulator, including proppant settlement due to gravity, tip screen-out, and fracture closure. Constitutive equations are used that account for processes that can cause the flowing fraction of proppant to be different from the volumetric fraction of proppant. The constitutive equations capture the transition from Poiseuille flow to Darcy flow as the slurry transitions from dilute mixture to packed bed. We introduce new constitutive equations that allow the simulator to seamlessly describe the process of fracture closure, including a nonlinear joint closure law expressing fracture compliance and roughness and accounting for the effect of proppant accumulation into a packed layer between the fracture walls.

Simulation of proppant transport with gravitational settling and fracture closure in a three-dimensional hydraulic fracturing simulator
Hydrulic Fracture
Hydraulic fracturing real-time evaluation technology provides an effective way to understand formation and fracturing, assess the quality of fracturing construct, and ensure the safety of fracturing construction. In this paper, com- bined with numerical simulation and data analysis, a new 3D model of real-time fracture extension is established on the basis of the theories of fluid dynamics, linear elastic fracture mechanics and computational mathematics. This model satis- fies the requirement of hydraulic fracturing real-time with the advantage of simple in form, precise and fast in computa- tion. Considering the influence of proppant on the friction calculation of sand mixed fluids, a wellbore flow model is de- veloped, which is more widely used and makes it no need of down-hole data acquisition.

Study of Hydraulic Fracturing Real-time Evaluation Technology
Uncategorized
Figure 7: Montney stratigraphic cross-section. Vertical scale bar on left side, 50 m. High-permeability turbidite channel and lobe deposits (yellow dotted pattern) are encased within tighter regional strata (orange shading). Line of section shown on Fig. 5. Well logs shown are natural gamma ray logs. Legend indicates depositional facies, sequence stratigraphy interpretation and well and drill-core information. Used with permission of GCSSEPM12. Turbidite deposits with superior matrix permeability are interpreted to form part of a preferential pathway for the secondary migration of methane (Fig. 4c). Turbidite deposition may have been influenced by syn-sedimentary faulting.

Secondary migration and leakage of methane from a major tight-gas system
Flow Mechanics
A mathematical dual porosity and dual permeability numerical model based on perpendicular bisection (PEBI) grid is developed to describe gas flow behaviors in shale-gas reservoirs by incorporating slippage corrected permeability and adsorbed gas effect. Parametric studies are conducted for a horizontal well with multiple infinite conductivity hydraulic fractures in shale-gas reservoir to investigate effect of matrix-wellbore flow, natural fracture porosity, and matrix porosity.

Effect of Matrix-Wellbore Flow and Porosity on Pressure Transient Response in Shale Formation Modeling by Dual Porosity and Dual Permeability System

Shale Basic Knowledge

Unconventional fields only produce hydrocarbons cost-effectively through stimulation treatments to large-scale, due to this, the determination of the mechanical properties of the formation and its variation along the same recover a greater importance in these "reservoirs" since these allow us to determine the degree of fracturability of the formation, select the optimal orientation of the wells and designing the fracture treatment. .shale formation modeling in a simulation through information acquired with seismic and well logs.

How to evaluate a shale play? Part B

0

HOW TO EVALUATE A SHALE PLAY? Part B Emanuel Martin In the first part of “HOW TO EVALUATE A SHALE PLAY?" we've developed: Shale play features, Main properties

is required to know the values of porosity, water saturation, permeability, reservoir volume and the volumetric factor of the gas or oil; the Total Organic Carbon (TOC), thermal maturity, depositional environment, mineralogical composition and mechanical properties.

How to evaluate a shale play? Part A

0

How to evaluate a shale play? Part A Emanuel Martin Introduction Shale formations constitute 60% of the rocks that make up the Earth's crust being only a small group

Pores in shale plays

WHERE IS THE GAS STORED? Shale Pores

0
Michigan Department of Environmental Quality website. Slurry blender, pump truck, proppant, van, Wellhead, Allaboutshale.com, shale handbook.

WHAT IS HYDRAULIC FRACTURING? PART B

0
Hydraulic Fracturing also known as fracking or fracing is a wells stimulation technique developed in 1947 by Stanolind Oil and aims to increase the drainage area and the performance of the same through the creation of fractures in the productive formation.

What is hydraulic fracturing? part A

0
Gray Shale rock from Vaca Muerta Formation, Neuquén, Argentina.

WHAT IS A SHALE?

0

Flow Mechanics

Shale Gas Productivity Predicting Model and Analysis of Influence Factor

Shale Gas Productivity Predicting Model and Analysis of Influence Factor

0

Abstract To know the dynamic characteristics of shale gas reservoirs’ production and to improve shale gas well production, it is very important to research on shale

A mathematical model of multistage fractured horizontal well (MsFHW) considering stimulated reservoir volume (SRV) was presented for tight oil reservoirs. Both inner and outer regions were assumed as single porosity media but had different formation parameters. Laplace transformation method, point source function integration method, superposition principle, Stehfest numerical algorithm, and Duhamel’s theorem were used comprehensively to obtain the semianalytical solution.

Rate Transient Analysis for Multistage Fractured Horizontal Well in Tight Oil Reservoirs considering Stimulated Reservoir Volume

0
The irregular morphology of single rock fracture significantly influences subsurface fluid flow and gives rise to a complex and unsteady flow state that typically cannot be appropriately described using simple laws. Yet the fluid flow in rough fractures of underground rock is poorly understood. Here we present a numerical method and experimental measurements to probe the effect of fracture roughness on the properties of fluid flow in fractured rock. We develop a series of fracture models with various degrees of roughness characterized by fractal dimensions that are based on the Weierstrass– Mandelbrot fractal function. The Lattice Boltzmann Method (LBM), a discrete numerical algorithm, is employed for characterizing the complex unsteady non-Darcy flow through the single rough fractures and validated by experimental observations under the same conditions.

Fractal model and Lattice Boltzmann Method for Characterization of Non-Darcy Flow in Rough Fractures

0
A mathematical dual porosity and dual permeability numerical model based on perpendicular bisection (PEBI) grid is developed to describe gas flow behaviors in shale-gas reservoirs by incorporating slippage corrected permeability and adsorbed gas effect. Parametric studies are conducted for a horizontal well with multiple infinite conductivity hydraulic fractures in shale-gas reservoir to investigate effect of matrix-wellbore flow, natural fracture porosity, and matrix porosity.

Effect of Matrix-Wellbore Flow and Porosity on Pressure Transient Response in Shale Formation Modeling by Dual Porosity and Dual Permeability System

0
Oil shale circulating fluidized bed combustion technology is a new technology and it is the most economical and efficient combustion way for using Oil shale resources. Nnumerical simulation of CFB is very important in the prediction of its flow behavior.

Numerical Simulation Research on Gas-Solid Two Phase Flow in Oil Shale Circulating Fluidized Bed

0

Reservoir Simulation

Productivity Model for Shale Gas Reservoir with Comprehensive Consideration of Multi-mechanisms

Productivity Model for Shale Gas Reservoir with Comprehensive Consideration of Multi-mechanisms

0

Abstract: Multi-stage fracturing horizontal well currently has been proved to be the most effective method to produce shale gas. This method can activate the natural fractures

Also at the well location, although the well may penetrate a productive shale, but in the same interval, away from the well location there might be non-productive shale sections. In other words, in unconventional shale reservoirs, productive shale zones and non-productive shale sections have randomly been distributed as illustrated in Fig. 3.

Well test, rate transient analysis and reservoir simulation for characterizing multi-fractured unconventional oil and gas reservoirs

0

Abstract Unconventional reservoirs such as shale gas and shale oil have become an increasingly important source of energy in the USA with potential reservoirs identified worldwide.

In this approach, a multi-fractured horizontal gas well in a shale formation is divided into four zones. Shale formation between each pair of hydraulic fractures consists of four zones: compacted zone around well-bore (1), shale matrix (2), induced fractures (3) and main hydraulic fractures (4). The main contribution of this study is considering varying permeability for each specific zone implemented in the mathematical presentation of gas flow in shale.

Unconventional Shale Reservoir’s Property Estimation through Modeling, Case Studies of Australian Shale

0
We build a compositional reservoir model to investigate the effects of complex fracture geometries on performance of CO2 Huff-n-Puff and CO2 continuous injection. The results confirm that the appropriate modelling of the fracture geometry plays a critical role in the estimation of the incremental oil recovery.

Simulation Study of CO2-EOR in Tight Oil Reservoirs with Complex Fracture Geometries

0
Modeling and simulation of unconventional reservoirs are much more complicated than the conventional reservoir modeling, because of their complex flow characteristics. Mechanisms, which control the flow in the reservoir, are still under the investigation of researchers.

Modeling and Simulation of Natural Gas Production from Unconventional Shale Reservoirs

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The characteristics of tight oil reservoir are low porosity and ultra-low permeability, thus stimulated reservoir volume (SRV) should be conducted whether applying the mode of vertical wells or horizontal wells production.

The Research of Gas Flooding of Horizontal Well with SRV in Tight Oil Reservoir

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Others

Analysis of bacterial diversity in two oil blocks from two low-permeability reservoirs with high salinities

Analysis of bacterial diversity in two oil blocks from two low-permeability reservoirs with high salinities

0
Understanding mechanisms of oil mobilization of tight matrix during CO2 injection is crucial for CO2 enhanced oil recovery (EOR) and sequestration engineering design. In this study exposure behavior between CO2 and tight rock of the Ordos Basin has been studied experimentally by using nuclear magnetic resonance transverse relaxation time (NMR T2) spectrum and magnetic resonance imaging (MRI) under the reservoir pressure and temperature.

Measurement and Visualization of Tight Rock Exposed to CO2 Using NMR Relaxometry and MRI

0
Logging Evaluation Method. Unconventional oil and gas resources, especially shale gas resources have great potential for exploration and development in China. In Shale gas exploration and development process, reservoir pore pressure is a very important parameter, and the pore pressure prediction can improve the appraisal accuracy of project dessert. This paper analyzes several formation pore pressure calculation methods based on logging data, and optimized the “Equivalent depth method”.

Logging Evaluation Method for Pore Pressure of Shale Gas Reservoirs— Taking Fuling area, Sichuan Basin as an example

0
Managing the wastewater discharged from oil and shale gas fields is a big challenge, because this kind of wastewater is normally polluted by high contents of both oils and salts. Conventional pressure-driven membranes experience little success for treating this wastewater because of either severe membrane fouling or incapability of desalination. In this study, we designed a new nanocomposite forward osmosis (FO) membrane for accomplishing simultaneous oil/water separation and desalination. This nanocomposite FO membrane is composed of an oil-repelling and salt-rejecting hydrogel selective layer on top of a graphene oxide (GO) nanosheets infused polymeric support layer.

A new nanocomposite forward osmosis membrane custom-designed for treating shale gas wastewater

0
Brittleness of rock plays a significant role in exploration and development of shale gas reservoirs. Young’s modulus and Poisson’s ratio are the key parameters for evaluating the rock brittleness in shale gas exploration because their combination relationship can quantitatively characterize the rock brittleness. The high-value anomaly of Young’s modulus and the low-value anomaly of Poisson’s ratio represent high brittleness of shale. The technique of pre-stack amplitude variation with angle inversion allows geoscientists to estimate Young’s modulus and Poisson’s ratio from seismic data.

Pre-stack basis pursuit seismic inversion for brittleness of shale

1
We developed a new direct shear test apparatus, coupled Hydro-Mechanical (HM), to investigate mechanical property variations when an intact rock experienced step drilling borehole, fluid injection, and fluid pressure acting on the borehole and fracture wall. We tested the peak shear stress of sandstone under different experimental conditions, which showed that drilling borehole, water injection, and increased pore pressure led to the decrease in peak shear stress.

An Experimental Investigation of the Risk of Triggering Geological Disasters by Injection under Shear Stress

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