Coal microstructure changes due to water absorption and CO2 injection

2016 ◽  
Vol 56 (2) ◽  
pp. 593 ◽  
Author(s):  
Yihuai Zhang ◽  
Mohammad Sarmadivaleh ◽  
Ahmed Barifcani ◽  
Maxim Lebedev ◽  
Stefan Iglauer
Keyword(s):  
Gas Production ◽  
Coal Bed ◽  
Co2 Injection ◽  
Micro Computed Tomography ◽  
Coal Seams ◽  
Coal Swelling ◽  
Coal Core ◽  
Porosity And Permeability ◽  
Microstructure Morphology ◽  
Mitigate Climate Change

Value from deep coal seams—too deep for mining—can nowadays be gained through natural gas production, so-called coal bed methane (CBM) recovery. To enhance such methane production (ECBM), CO2 can be injected into such coal seams—that are also a potential sink for CO2—to mitigate climate change. During this process CO2 is absorbed into the coal matrix, which can lead to a dramatic porosity and permeability change. The underlying changes in coal microstructure—despite their obvious importance for permeability and production—are only poorly understood. The authors thus imaged coal core plugs at high spatial resolution (3.4 μm) in 3D with an X-ray micro-computed tomography. Medium rank coal plugs were cut and imaged at dry and brine saturated state, and after CO2 injection. During brine flooding the authors observed a clear and significant change in microstructure morphology; while the solid volume clearly expanded significantly (coal swelling), cleats closed and permeability was reduced dramatically.

scholarly journals NUMERICAL MODELLING AND SIMULATION OF CO2 –ENHANCED COAL-BED METHANE RECOVERY (CO2-ECBMR): THE EFFECT OF COAL SWELLING ON GAS PRODUCTION PERFORMANCE

2015 ◽  
Vol 7 (2) ◽  
pp. 102
Author(s):  
Ferian Anggara ◽  
Kyuro Sasaki ◽  
Yuichi Sugai
Keyword(s):  
Gas Production ◽  
Production Performance ◽  
Coal Bed ◽  
Methane Recovery ◽  
Coal Matrix ◽  
Ch4 Production ◽  
Coal Swelling ◽  
Production Ratio ◽  
Permeability Changes ◽  
Production Wells

This presents study investigate the effect of swelling on gas production performances at coal reservoirs during CO2-ECBMR processes. The stressdependent permeability-models to express effect of coal matrix shrinkage/swelling using Palmer and Mansoori (P&M) and Shi and Durucan (S&D) models were constructed based on present experimental results for typical coal reservoirs with the distance of 400 to 800 m between injection and production wells. By applying the P&M and S&D models, the numerical simulation results showed that CH4 production rate was decreasing and peak production time was delayed due to effect of stress and permeability changes caused by coal matrix swelling. The total CH4 production ratio of swelling effect/no-swelling was simulated as 0.18 to 0.95 for permeability 1 to 100 mD, respectively. It has been cleared that swelling affects gas production at permeability 1 to 15 mD, however, it can be negligible at permeability over 15 mD.

CO2 Injection Performance in the Fruitland Coal Fairway, San Juan Basin: Results of a Field Pilot

SPE Journal ◽  
2011 ◽  
Vol 16 (04) ◽  
pp. 864-879 ◽  
Author(s):  
Anne Y. Oudinot ◽  
George J. Koperna ◽  
Zeno G. Philip ◽  
Ning Liu ◽  
Jason E. Heath ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
The United States ◽  
Gas Production ◽  
Injection Well ◽  
Co2 Injection ◽  
Small Scale ◽  
Steady Increase ◽  
San Juan ◽  
Coal Seams ◽  
Production Wells

Summary The Pump Canyon CO2-enhanced coalbed methane (ECBM)/ sequestration demonstration in New Mexico has the primary objective of demonstrating the feasibility of CO2 sequestration in deep, unmineable coal seams through a small-scale geologic sequestration pilot. This project is not the first of its kind; several small- or large-scale pilots were already conducted previously in the United States [Allison Unit (Reeves et al. 2003) in the San Juan, Appalachian, and Warrior basins] as well as internationally [the Recopol (Reeves and Oudinot 2002) project in Poland, and the Yubari project in Japan, Canada, and Australia]. Additional pilots are currently under way. At the project site, a new CO2-injection well was drilled within an existing pattern of coalbed-methane-production wells. Primarily operated by ConocoPhillips, these wells produce from the Late Cretaceous Fruitland coals. CO2 injection into these coal seams was initiated in late July 2008 and ceased in August 2009. A variety of monitoring, verification, and accounting (MVA) methods were employed to track the movement of the CO2 in order to determine the occurrence of leakage. Within the injection well, MVA methods included continuous measurement of injection volumes, pressures, and temperatures. The offset production wells sampled gas-production rates, pressures, and gas composition through CO2 sensors, tracers in the injected CO2, time-lapse vertical seismic profiling, and surface tiltmeter arrays. A detailed study of the overlying Kirtland shale was also conducted to investigate the integrity of this primary caprock. This information was used to develop a detailed geologic characterization and reservoir model that has been used to further understand the behavior of this reservoir. The CO2-injection pilot has ended with no significant CO2 buildup occurring in the offset production wells. However, a small but steady increase in CO2 and N2 at two of the offset wells may have been an indication of imminent breakthrough. More recent gas samples are, however, showing a decrease in CO2 and N2 content at those wells. This paper describes the project, covering the regulatory process and injection-well construction, the different techniques used to monitor for CO2 leakage, and the results of the modeling work.

What Hit and Miss in Indonesia CBM Project : Empirical Study Slowing Down Factors CBM Development and Propose Suitable Action for CBM Development in Indonesia by Using Analytical Hierarch Process.

2021 ◽  
Author(s):  
I.A. Firdaus
Keyword(s):  
Oil And Gas ◽  
Economic Value ◽  
Gas Production ◽  
Coal Bed ◽  
Production Sharing ◽  
High Investment ◽  
The Government ◽  
Exploration Period ◽  
Production Areas ◽  
Testing Standards

In 2008, the first Coal Bed Methane (CBM) PSC was signed in Indonesia. To date, 54 CBM PSCs have been awarded to explore and develop CBM Block in Indonesia. Twelve years later, only one PSC has submitted a Plan of Development but has not yet produced gas commercially. Most CBM PSCs have been struggling during the 10 years’ exploration period and some may receive extensions for 3 years under specific conditions. The lack of integrated authorities’ approval in the overlay of coal mining and natural gas production areas has become a great obstacle for CBM Development. Besides that, the government regulations in CBM activities have defects in PSC contract terms that may lead marginal economic value for contractors, especially due to high investment during the early development (C. Irawan, 2017). On the other hand, drilling regulations, Pipe Classing standards and Testing Standards following the Oil and Gas standards are too expensive for CBM Investment. According to our observations, CBM Regulations in Indonesia should be modified starting from the Exploration period, Production Sharing Contract Terms and Standard Operating Procedures to suit Indonesian CBM characteristics. Good coordination within government departments is a must for the success of CBM Exploration and Development.

A Leap into Automation for Advanced Fracture Characterization

2021 ◽  
Author(s):  
Radhika Patro ◽  
Manas Mishra ◽  
Hemlata Chawla ◽  
Sambhaji Devkar ◽  
Mrinal Sinha ◽  
...  
Keyword(s):  
Machine Learning ◽  
Fracture Network ◽  
Unconventional Reservoirs ◽  
Machine Learning Techniques ◽  
Coal Bed ◽  
Fracture Characterization ◽  
Learning Techniques ◽  
Macro Scale ◽  
Porosity And Permeability ◽  
Depth Of Investigation

Abstract Fractures are the prime conduits of flow for hydrocarbons in reservoir rocks. Identification and characterization of the fracture network yields valuable information for accurate reservoir evaluation. This study aims to portray the benefits and limitations for various existing fracture characterization methods and define strategic workflows for automated fracture characterization targeting both conventional and unconventional reservoirs separately. While traditional seismic provides qualitative information of fractures and faults on a macro scale, acoustics and other petrophysical logs provide a more comprehensive picture on a meso and micro level. High resolution image logs, with shallow depth of investigation are considered the industry standard for analysis of fractures. However, it is imperative to understand the framework of fracture in both near and far field. Various reservoir-specific collaborative workflows have been elucidated for a consistent evaluation of fracture network, results of which are further segregated using class-based machine learning techniques. This study embarks on understanding the critical requirements for fracture characterization in different lithological settings. Conventional reservoirs have good intrinsic porosity and permeability, yet presence of fractures further enhances the flow capacity. In clastic reservoirs, fractures provide an additional permeability assist to an already producible reservoir. In carbonate reservoirs, overall reservoir and production quality exclusively depends on presence of extensive fracture network as it quantitatively controls the fluid flow interactions among otherwise isolated vugs. Devoid of intrinsic porosity and permeability, the presence of open-extensive fractures is even more critical in unconventional reservoirs such as basement, shale-gas/oil and coal-bed methane, since it demarcates the reservoir zone and defines the economic viability for hydrocarbon exploration in reservoirs. Different forward modeling approaches using the best of conventional logs, borehole images, acoustic data (anisotropy analysis, borehole reflection survey and stoneley waveforms) and magnetic resonance logs have been presented to provide reservoir-specific fracture characterization. Linking the resolution and depth of investigation of different available techniques is vital for the determination of openness and extent of the fractures into the formation. The key innovative aspect of this project is the emphasis on an end-to-end suitable quantitative analysis of flow contributing fractures in different conventional and unconventional reservoirs. Successful establishment of this approach capturing critical information will be the stepping-stone for developing machine learning techniques for field level assessment.

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