Download or read book Noble Gas Tracing of Fluid Transport in Shale Reservoirs written by and published by . This book was released on 2014 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Appraisal of Transport and Deformation in Shale Reservoirs Using Natural Noble Gas Tracers written by and published by . This book was released on 2015 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report presents efforts to develop the use of in situ naturally-occurring noble gas tracers to evaluate transport mechanisms and deformation in shale hydrocarbon reservoirs. Noble gases are promising as shale reservoir diagnostic tools due to their sensitivity of transport to: shale pore structure; phase partitioning between groundwater, liquid, and gaseous hydrocarbons; and deformation from hydraulic fracturing. Approximately 1.5-year time-series of wellhead fluid samples were collected from two hydraulically-fractured wells. The noble gas compositions and isotopes suggest a strong signature of atmospheric contribution to the noble gases that mix with deep, old reservoir fluids. Complex mixing and transport of fracturing fluid and reservoir fluids occurs during production. Real-time laboratory measurements were performed on triaxially-deforming shale samples to link deformation behavior, transport, and gas tracer signatures. Finally, we present improved methods for production forecasts that borrow statistical strength from production data of nearby wells to reduce uncertainty in the forecasts.
Download or read book Transport in Shale Reservoirs written by Kun Sang Lee and published by Gulf Professional Publishing. This book was released on 2019-02-20 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transport in Shale Reservoirs fills the need for a necessary, integrative approach on shale reservoirs. It delivers both the fundamental theories of transport in shale reservoirs and the most recent advancements in the recovery of shale oil and gas in one convenient reference. Shale reservoirs have distinctive features dissimilar to those of conventional reservoirs, thus an accurate evaluation on the behavior of shale gas reservoirs requires an integrated understanding on their characteristics and the transport of reservoir and fluids. Updates on the various transport mechanisms in shale, such as molecular diffusion and phase behavior in nano-pores Applies theory to practice through simulation in both shale oil and gas Presents an up-to-date reference on remaining challenges, such as organic material in the shale simulation and multicomponent transport in CO2 injection processes
Download or read book Advancements of Phase Behavior and Fluid Transport in Petroleum Reservoirs written by Xiaohu Dong and published by Frontiers Media SA. This book was released on 2022-06-30 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Multiscale Investigation of Fluid Transport in Gas Shales written by Robert J. Heller and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis focuses on developing an improved understanding of fluid flow in gas shales. The problem is studied at multiple scales, and using a variety of approaches spanning several disciplines. In Chapter 2, Adsorption of Methane and Carbon Dioxide on Gas Shale and Pure Mineral Samples, we present measurements of methane and carbon dioxide adsorption isotherms at 40°C on gas shale samples from the Barnett, Eagle Ford, Marcellus and Montney reservoirs. Carbon dioxide isotherms were included to assess its potential for preferential adsorption, with implications for its use as a fracturing fluid and/or storage in depleted shale reservoirs. To better understand how the individual mineral constituents that comprise shales contribute to adsorption, measurements were made on samples of pure carbon, illite and kaolinite as well. The resultant volumetric swelling strain was also measured as a function of pressure/adsorption. In Chapter 3, Experimental Investigation of Matrix Permeability of Gas Shales, we present laboratory experiments examining the effects of confining stress and pore pressure on permeability. Experiments were carried out on intact core samples from the Barnett, Eagle Ford, Marcellus and Montney shale reservoirs. The methodology we used to measure permeability allows us to separate the reduction of permeability with depletion (due to the resultant increase in effective confining stress) and the increase in permeability associated with Knudsen diffusion and molecular slippage (also known as Klinkenberg) effects at very low pore pressure. By separating these effects, we are able to estimate the relative contribution of both Darcy and diffusive fluxes to total flow in depleted reservoirs. Our data show that the effective permeability of the rock is significantly enhanced at very low pore pressures (
Download or read book Fundamentals of Gas Shale Reservoirs written by Reza Rezaee and published by John Wiley & Sons. This book was released on 2015-07-01 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides comprehensive information about the key exploration, development and optimization concepts required for gas shale reservoirs Includes statistics about gas shale resources and countries that have shale gas potential Addresses the challenges that oil and gas industries may confront for gas shale reservoir exploration and development Introduces petrophysical analysis, rock physics, geomechanics and passive seismic methods for gas shale plays Details shale gas environmental issues and challenges, economic consideration for gas shale reservoirs Includes case studies of major producing gas shale formations
Download or read book Shale written by Thomas Dewers and published by John Wiley & Sons. This book was released on 2019-10-15 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in theories, methods and applications for shale resource use Shale is the dominant rock in the sedimentary record. It is also the subject of increased interest because of the growing contribution of shale oil and gas to energy supplies, as well as the potential use of shale formations for carbon dioxide sequestration and nuclear waste storage. Shale: Subsurface Science and Engineering brings together geoscience and engineering to present the latest models, methods and applications for understanding and exploiting shale formations. Volume highlights include: Review of current knowledge on shale geology Latest shale engineering methods such as horizontal drilling Reservoir management practices for optimized oil and gas field development Examples of economically and environmentally viable methods of hydrocarbon extraction from shale Discussion of issues relating to hydraulic fracking, carbon sequestration, and nuclear waste storage Book Review: I. D. Sasowsky, University of Akron, Ohio, September 2020 issue of CHOICE, CHOICE connect, A publication of the Association of College and Research Libraries, A division of the American Library Association, Connecticut, USA Shale has a long history of use as construction fill and a ceramic precursor. In recent years, its potential as a petroleum reservoir has generated renewed interest and intense scientific investigation. Such work has been significantly aided by the development of instrumentation capable of examining and imaging these very fine-grained materials. This timely multliauthor volume brings together 15 studies covering many facets of the related science. The book is presented in two sections: an overview and a second section emphasizing unconventional oil and gas. Topics covered include shale chemistry, metals content, rock mechanics, borehole stability, modeling, and fluid flow, to name only a few. The introductory chapter (24 pages) is useful and extensively referenced. The lead chapter to the second half of the book, "Characterization of Unconventional Resource Shales," provides a notably detailed analysis supporting a comprehensive production workflow. The book is richly illustrated in full color, featuring high-quality images, graphs, and charts. The extensive index provides depth of access to the volume. This work will be of special interest to a diverse group of investigators moving forward with understanding this fascinating group of rocks. Summing Up: Recommended. Upper-division undergraduates through faculty and professionals.
Download or read book The Noble Gases as Geochemical Tracers written by Pete Burnard and published by Springer Science & Business Media. This book was released on 2012-12-15 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: The twelve chapters of this volume aim to provide a complete manual for using noble gases in terrestrial geochemistry, covering applications which range from high temperature processes deep in the Earth’s interior to tracing climatic variations using noble gases trapped in ice cores, groundwaters and modern sediments. Other chapters cover noble gases in crustal (aqueous, CO2 and hydrocarbon) fluids and laboratory techniques for determining noble gas solubilities and diffusivities under geologically relevant conditions. Each chapter deals with the fundamentals of the analysis and interpretation of the data, detailing sampling and sampling strategies, techniques for analysis, sources of error and their estimation, including data treatment and data interpretation using recent case studies.
Download or read book Study of Multi scale Transport Phenomena in Tight Gas and Shale Gas Reservoir Systems written by Craig Matthew Freeman and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The hydrocarbon resources found in shale reservoirs have become an important energy source in recent years. Unconventional geological and engineering features of shale systems pose challenges to the characterization of these systems. These challenges have impeded efficient economic development of shale resources. New fundamental insights and tools are needed to improve the state of shale gas development. Few attempts have been made to model the compositional behavior of fluids in shale gas reservoirs. The transport and storage of reservoir fluids in shale is controlled by multiple distinct micro-scale physical phenomena. These phenomena include preferential Knudsen diffusion, differential desorption, and capillary critical effects. Together, these phenomena cause significant changes in fluid composition in the subsurface and a measureable change in the composition of the produced gas over time. In order to quantify this compositional change we developed a numerical model describing the coupled processes of desorption, diffusion, and phase behavior in heterogeneous ultra-tight rocks as a function of pore size. The model captures the various configurations of fractures induced by shale gas fracture stimulation. Through modeling of the physics at the macro-scale (e.g. reservoir-scale hydraulic fractures) and micro-scale (e.g. Knudsen diffusion in kerogen nanopores), we illustrate how and why gas composition changes spatially and temporally during production. We compare the results of our numerical model against measured composition data obtained at regular intervals from shale gas wells. We utilize the characteristic behaviors explicated by the model results to identify features in the measured data. We present a basis for a new method of production data analysis incorporating gas composition measurements in order to develop a more complete diagnostic process. Distinct fluctuations in the flowing gas composition are shown to uniquely identify the onset of fracture interference in horizontal wells with multiple transverse hydraulic fractures. The timescale and durations of the transitional flow regimes in shales are quantified using these measured composition data. These assessments appear to be robust even for high levels of noise in the rate and pressure data. Integration of the compositional shift analysis of this work with modern production analysis is used to infer reservoir properties. This work extends the current understanding of flow behavior and well performance for shale gas systems to encompass the physical phenomena leading to compositional change. This new understanding may be used to aid well performance analysis, optimize fracture and completion design, and improve the accuracy of reserves estimates. In this work we contribute a numerical model which captures multicomponent desorption, diffusion, and phase behavior in ultra-tight rocks. We also describe a workflow for incorporating measured gas composition data into modern production analysis. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/151782
Download or read book Petrophysical Characterization and Fluids Transport in Unconventional Reservoirs written by Jianchao Cai and published by Elsevier. This book was released on 2019-01-24 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Petrophysical Characterization and Fluids Transport in Unconventional Reservoirs presents a comprehensive look at these new methods and technologies for the petrophysical characterization of unconventional reservoirs, including recent theoretical advances and modeling on fluids transport in unconventional reservoirs. The book is a valuable tool for geoscientists and engineers working in academia and industry. Many novel technologies and approaches, including petrophysics, multi-scale modelling, rock reconstruction and upscaling approaches are discussed, along with the challenge of the development of unconventional reservoirs and the mechanism of multi-phase/multi-scale flow and transport in these structures. Includes both practical and theoretical research for the characterization of unconventional reservoirs Covers the basic approaches and mechanisms for enhanced recovery techniques in unconventional reservoirs Presents the latest research in the fluid transport processes in unconventional reservoirs
Download or read book Study of Flow Mechanisms in Shale Using CT Imaging and Data Analytics written by Beibei Wang and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the decline of current conventional oil and gas reservoirs, the development of unconventional resources has received great attention in recent years (World Energy Outlook 2012). Shale, formations that are considered as both source rocks and reservoirs, play a significant role in the USA's hydrocarbon production (EIA 2019). Hence, understanding the effective and efficient development of unconventional resources is of crucial importance. Nevertheless, there are still numerous technical challenges related to fluid transport in shale. The nanoporous system of shale formations has relatively low porosity and ultralow permeability that has considerable influence on fluid transport by advection and diffusion (Javadpour et al., 2007). Moreover, cracks and natural fractures are also very common in shale and they play a very important role in production. Natural cracks and fractures contribute directly to storage and permeability, and they can interact with hydraulic fracturing treatments (Gale et al., 2010). The heterogeneous pore and network system together with the significant variation in mineral composition raise challenges for the understanding of fluid transport through shale. Mechanistic understanding of fluid transport in shale reservoirs is crucial for future production forecasts and for better field planning and development. This research work bridges the gap in understanding the storage and transport mechanisms of unconventional resources. Various experimental, simulation and data analysis techniques were applied, as follows. First, simulation of adsorption properties using statistical modelling based on Grand Canonical Monte Carlo (GCMC) techniques for CO2 adsorption in clay systems was performed. Significant CO2 is predicted to adsorb to clay. Results from simulation and experiment are compared to further investigate the adsorption properties of gas shale and to predict the adsorbed phase densities as a function of temperature, pressure, and pore size. It was observed that the simulated CO2 adsorption for the clay is smaller compared to organic matter. This result shows the same trend as the experimental measurement. At 60 bar and 80 °C, the CO2 adsorption in a 2 nm pore in clay is around 2 mmol/cm3; while in the 2 nm pore in the organic matter, the CO2 adsorption is around 13 mmol/cm3. Second, we carried out experiments to probe liquid behaviour in shale samples by X-ray CT imaging. CT scans were taken continuously after injecting water and water tracer into the core. From the change of CT signal of the shale core over time as the water flows through the porous medium, the water flow path is visualized. From CT image analysis, when injecting water into the dry core, a water front was observed to move along the core over time. The CT signal of the entire core increased substantially after breakthrough indicating that water preferably flowed through larger pore space and then transported into the matrix. Third, following on the success of imaging liquid movement in shale, experiments were carried out to visualize and study liquid diffusion in sandstone, carbonate, and two shale samples. The diffusion study is designed to be purely concentration driven with no pressure difference applied to the system. An effective diffusion coefficient was calculated by fitting the experimentally measured concentration profile data and analytical solutions from Fick's law. Then, sample tortuosity was analyzed based on the effective diffusion. The sandstone and carbonate had tortuosities of 1.34 and 1.36, respectively, in agreement with literature. The shale samples had tortuosity in excess of 10 indicating substantial geometrical complexity of shale porous networks. Finally, a data-driven deep learning approach was developed to infer the permeability distribution of shale samples. Through analyzing flow images of the shale sample from CT scans, a convolutional neural network model was trained to calculate the average and local permeability of the sample. Compared to traditional permeability measurement and calculation, this method presents a local 3-D permeability map of the shale and provides valuable information to understand the nature of shale and their production capabilities.
Download or read book Influence of Nanopores on the Transport of Gas and Gas condensate in Unconventional Resources written by Maytham I. Al Ismail and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Shale gas and liquid-rich shales have become important energy sources in the US and other parts of the world. Unlike conventional oil and gas reservoirs, unconventional shale resources contain a very heterogeneous pore system. The pore size varies between micro-, meso- and macroscales (2 nm, 2-50 nm and 50 nm). The mineral composition of shale rocks varies widely as well from clay-rich to calcite-rich. The nanoscale nature of the pores, coupled with rock mineral heterogeneity, makes the "conventional'' understanding of fluid transport in conventional reservoirs no longer suitable to explain and predict accurately the flow behavior in unconventional resources. The research work aimed to bridge the gap in the understanding of the fluid flow behavior of unconventional resources by applying various experimental and molecular simulation tools. Specifically, this research work studied how the rock (i.e. permeability), the fluid (i.e. composition and phase behavior) and the fluid-rock interactions (i.e. adsorption) all behaved with depletion in nanoporous rock formations. Several laboratory experiments and molecular simulation techniques were applied in this research work. Laboratory experiments included a gas-condensate core-flooding experiment, permeability measurements and adsorption measurements. In the core-flooding experiment, a real gas-condensate mixture obtained from the Marcellus shale play was injected into a Marcellus shale core at in-situ conditions and the composition of gas samples collected along the core was monitored during flow. To investigate the effect of rock mineralogy and pore structure on the transport mechanisms in nanoporous shale reservoirs, the permeability of Utica, Permian and Eagle Ford shale samples were measured using argon as a nonadsorbing gas and CO2 as an adsorbing gas. In addition, CO2 adsorption experiments were conducted on different shale samples in order to investigate the role of shale mineral constituents in adsorption. Moreover, molecular simulation techniques were applied to model the selective adsorption of binary hydrocarbon mixtures in carbon-based slit-pores and to estimate the shift in the critical properties of hydrocarbons due to confinement in nanometer-size pores. The molecular simulation techniques included the grand canonical Monte Carlo (GCMC) and the Gibbs ensemble Monte Carlo (GEMC). This research work revealed that clay content in shale reservoirs played a significant role in the stress-dependent permeability. For clay-rich samples, higher pore throat compressibility was observed which in turn led to higher permeability reduction with increasing effective stress compared to calcite-rich samples. Numerical simulation results showed that failing to account for stress-dependent permeability in clay-rich shale reservoirs may lead to overestimating the cumulative gas recovery by a factor of two after ten years of production. Permeability measurements with CO2 indicated that CO2 permeability decreased in comparison with the nonadsorbing gases by as high as an order of magnitude due to a combination of CO2 adsorption, sorption-induced swelling and molecular sieving effects. CO2 adsorption measurements indicated that adsorption was controlled mainly by the clay content. Clay-rich shale samples showed higher adsorption capacity compared to clay-poor shale samples. The predominant clay mineral in those shale samples was illite. The platy shape of illite provided the surface area for enhanced adsorption capacity. This study concluded that in gas-condensate systems of liquid-rich shales, the produced gas becomes leaner during production and significant volumes of condensates, which contain predominantly heavy components, are left behind in the reservoir. The gas-condensate core-flooding experiment showed that composition of the flowing mixture below the dew-point pressure contained less heavy components along the direction of flow. Molecular simulations revealed that the change in gas composition was not only due to condensate dropout and relative permeability effects, but also due to the preferential adsorption of heavy hydrocarbons over methane. This means that initial production from shale reservoirs contain both methane and other heavy components from the free phase. However, as reservoir pressure decreases, methane from the adsorbed phase starts to desorb preferentially and the adsorption sites where methane molecules used to reside start to accept heavier components. In addition, molecular simulations conducted at subcritical conditions to estimate the vapor and liquid densities of pure hydrocarbons inside 5 and 10-nm pores revealed that rock-fluid interactions in the form of adsorption caused the critical pressure and temperature of the confined molecules to decrease. This was observed clearly for methane and ethane. The decrease in the critical properties was affected by the size of the pores. For example, the estimated critical pressure and temperature of methane in 5-nm pore were lower than the critical pressure and temperature in 10-nm pore.
Download or read book Modeling and Simulation of the Pore scale Multiphase Fluid Transport in Shale Reservoirs written by Gorakh Pawar and published by . This book was released on 2016 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modelling in Nanoporous Shale written by Liehui Zhang and published by Springer. This book was released on 2024-10-26 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses the problems involved in the modelling and simulation of shale gas reservoirs at pore scale, and details recent advances in the field. It presents the construction of simulation methods, mainly using the lattice Boltzmann method (LBM), that describe sorption, flow, and transport in nanoporous shale with some case studies. This book highlights the nanoscale effects, ascribed to the large surface-to-volume ratio, on fluids occurrence and transport physics. It discusses some interesting phenomena occurs at nanoporous shale, such as absorbed water film, water condensation, sorption hysteresis, surface excess adsorption, Knudsen diffusion, surface diffusion, structural fluid density, no-slip boundary, etc. The key techniques and methods introduced in this book provide the basis for accurate prediction of gas-well productivity. The basic principles and modeling methods are also relevant to many other nanoporous applications in science and engineering. The book aims to provide a valuable reference resource for researchers and professional scientists and engineers working on shale gas development and nanoporous media research.
Download or read book Multiscale Investigation of Fluid Transport and Enhanced Recovery in Shale written by Youssef Magdy Abdou Mohamed Elkady and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In 2019, the U.S. produced 75% of its natural gas from shales and 59% of its oil from tight oil resources. Multistage hydraulic fracturing along with horizontal pad drilling enabled operators to increase significantly production from these resources. Despite the vastness of shale resources, recovery factors are small typically, amounting to 5-10% for oil and ~25% for gas. In this work we examine various enhanced recovery techniques across multiple length scales to gain a better understanding of enhanced resource recovery mechanisms resulting from injection of gas, such as carbon dioxide (CO2). In doing so, we develop in-house shale characterization experimental methods to quantify fluid flow, storage, and recovery in the laboratory. An experimental workflow is presented for rock characterization (porosity, permeability, and adsorption) to quantify accurately gas storage and flow needed for enhanced gas recovery (EGR) experiments. Both pulse decay and Computed Tomography (CT) were used independently to establish consistency between results derived from each method. New image processing routines for CT data were developed that better match mass balance derived porosity and storativity results compared to conventional CT methods. Measured porosity values using helium (He) for each sample proved to be constant at various equilibrium pore pressures justifying its use as a reference gas for excess adsorption computations for other gases studied. Nitrogen (N2), methane (CH4), krypton (Kr), and CO2 apparent permeability and storativity at different pore pressures were determined. All adsorptive gases, except CO2, exhibited monolayer Langmuir adsorption behavior. CO2 uniquely showed multilayer behavior that was observed in two cores (Eagle Ford (EF1) and Wolfcamp (WC2)). The impact of adsorption on gas permeability was captured in our experiments showing a negative correlation between adsorption affinity and permeability. For instance, Kr and CO2 reduced the liquid-like permeability value determined using He by factors of 2 and 8, respectively, for sample EF1. Finally, a persistent five-fold reduction in permeability was observed in sample WC2 after CO2 exposure that is attributed to kerogen swelling or matrix softening. The degree of kerogen swelling is impacted by the affinity of the gas to adsorb and its ability to dissolve into kerogen. Matrix softening, on the other hand, enhances compaction of the pore space under constant effective stresses. Diverse diagnostics across multiple scales were used to examine the impact of CO2-water fluids on oil recovery and matrix flow on both core and micron scales. Enhanced oil recovery (EOR) was investigated on a Utica (W2-2) core that was artificially split and saturated with crude oil for 3 months. The core was cut to create a conductive pathway and to increase surface area to help oil saturate the sample. Core-scale examinations using pulse decay, injection experiments, and CT showed no material enhancement to matrix fluid flow or oil recovery using dry supercritical CO2, water-saturated CO2, or carbonated water. Approximately 87% of the in-situ oil was recovered using dry supercritical CO2 initially without any further recovery. CT visualizations showed that most of the oil resided in the main fracture with small amounts of oil residing in the matrix. Potential enhancement in core-scale matrix flow was investigated by conducting He pressure pulses before and after a carbonate-rich Eagle Ford (EF-1) sample was exposed to carbonated water for 6 months. Measured permeability values were identical before and after exposure to the acidic fluid. Micron-scale findings, on the other hand, using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and micro-CT showed vugs and pits, from calcite dissolution, ranging from 1 micro-m to 10's micro-m in size in samples exposed to carbonated water. These samples were exposed to carbonated water in either a batch reactor setting or a core-scale carbonated water injection experiment. The wet supercritical CO2 phase did not induce any observable carbonate dissolution in the shale sample tested. Finally, it was determined that gold coating of the sample (a preparation step needed for SEM imaging) has no impact on fluid-rock interaction during our experiments. A novel experimental setup was designed for investigating EGR in shale cores. The detailed sample characterization conducted on both samples (EF1 and WC2) was used to assess initial rock storativity, adsorption, and permeability that are vital for proper experimental planning given the small pore volumes in shales. Experiments were run with Kr or CH4 as in-situ gases and CO2 or N2 as injection gases. Continuous Kr gas injection experiments showed consistent results between mass balance and CT-derived results establishing reliability in our CT depictions. CO2 gas injection had a better initial displacement efficiency compared to N2 when displacing in-situ Kr. Homogeneous sample WC2 required approximately four times fewer pore volume injections to produce the entire original gas in place compared to sample EF1 that had two CT-visible conductive pathways or microcracks. Finally, core-scale findings reveal that continuous gas injection is more effective than huff-n-puff for enhancing gas recovery on a pore volume injected basis. Core-scale simulations using CMG GEM were created to mimic and validate lab pulse decay and EGR experiments. Porosity, permeability, and adsorption values were validated for various pressure pulses across both cores (EF1 and WC2) using all the gases investigated (He, N2, Kr, CH4, and CO2). Coal bed methane modeling in CMG GEM was utilized for matching highly adsorptive gases (Kr and CO2) due to a delayed downstream response given the experimentally determined porosity, permeability, and adsorption values. Another critical parameter, diffusion characteristic time (t*), was identified using this model during the history matching process that quantifies a mass transfer resistance to fracture flow due to fracture-matrix gas exchange. Although our experiments were not designed to measure directly t*, various pressure pulses for CO2 and Kr required a diffusion time of 1.44-1.92 hrs (0.06-0.08 days) to match our pressure pulses using coal bed methane modeling. A continuous gas injection experiment was simulated in CMG GEM that matched the experimental pressure history, recovery results, and CT visualizations for sample EF1. Sensitivity studies on diffusion time revealed its strong influence on recovery in low permeability areas that are predominant during late production. A huff-n-puff experiment was simulated given the same model parameters as the history matched continuous injection experiment. Huff-n-puff had a poorer recovery curve compared to continuous injection due to gas entrapment away from the microcracks with each cycle. Finally, core-scale simulations show that long diffusion times are favorable for huff-n-puff but disadvantageous for continuous injection emphasizing the importance of sample characterization, including transport properties, before evaluating the different EGR techniques. Learnings from core-scale experiments and simulations were translated to assess EGR applicability at field scale. Multiple reservoir uncertainties (porosity, stimulated permeability, diffusion time) and operational decisions (e.g. injection and soak times) were explored to understand their influence on CH4 recovery and CO2 storage for continuous injection and huff-n-puff. A simplified CMG GEM field model was created that utilized 1300 m horizontal wells that have 13 fracture stages with 4 clusters per stage. Field continuous injection scenarios yielded a loss in cumulative CH4 production compared to cases with primary production only over a 20 year period. Injection started after 10 years of primary production; however, the economic benefits from CO2 storage outweighed CH4 losses in cases with short diffusion times (
Download or read book From Source to Seep written by M. Lawson and published by Geological Society of London. This book was released on 2018-03-28 with total page 210 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrocarbon systems, by nature, are a complex interplay of elements that must be spatially and temporally aligned to result in the generation and preservation of subsurface hydrocarbon accumulations. To meet the increasing challenges of discovering hydrocarbon resources, it is essential that we advance our understanding of these systems through new geochemical approaches and analytical developments. Such development requires that academic- and industry-led research efforts converge in ways that are unique to the geosciences. The aim of this volume is to bring together a multidisciplinary geochemical community from industry and academia working in hydrocarbon systems to publish recent advances and state-of-the-art approaches to resolve the many remaining questions in hydrocarbon systems analysis. From Source to Seep presents geochemical and isotopic studies that are grouped into three themes: (1) source-rock identification and the temperature/timing of hydrocarbon generation; (2) mechanisms and time-scales associated with hydrocarbon migration, trapping, storage and alteration; and (3) the impact of fluid flow on reservoir properties.
