Day 4 Thu, November 15, 2018最新文献

{"title":"Combined use of Optical-fiber DAS and a Permanent Seismic Source for Vertical Seismic Profiling Demonstrated at the Aquistore CO2 Storage Site","authors":"M. Nakatsukasa, H. Ban, A. Kato, N. Shimoda, D. White, E. Nickel, T. Daley","doi":"10.2118/193268-MS","DOIUrl":"https://doi.org/10.2118/193268-MS","url":null,"abstract":"\u0000 Seimic reservoir monitoring is a method to monitor fluid displacement in the reservoir. Long-term monitoring to measure differences over several years has been successful recently. However, short-term monitoring to measure changes in nearly real-time is still challenging because the expected changes in such a short-term are small. Permanent reservoir monitoring might enable short-term monitoring because we can increase data repeatability since sources and receivers are permanently fixed at the same position. This method saves the acquisition cost once the equipment is deployed, but the number of sources and receivers is limited due to the high initial install cost. To address this challenge, we have demonstrated VSP monitoring with a combination of a permanent rotary source and DAS sensor. DAS can record a wavefield at very dense and extensive points along an optical fiber, but the quality is regarded as less than for conventional geophones. By comparing data recorded in 2015 and 2016, we investigated the improvement of the signal-to-noise ratio of DAS. Hourly repeatability was checked by arranging the waveforms by the acquisition time. The depth migrated image of the offset VSP extended the imaging are further away from the receiver well. Our study confirmed the complementary relationship between the permanent source and DAS acquisition. Combining these technologies might enable us to monitor small changes in the reservoir in the short-term.","PeriodicalId":11079,"journal":{"name":"Day 4 Thu, November 15, 2018","volume":"28 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82112942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel Perforating Design Delivers Production Targets Safely and Efficiently in Gas Producing Wells","authors":"Nasr Awad, Ashraf Abdel Sattar, M. Sheha, A. Moustafa, M. Vazquez, A. Farid, Alaa Mohamedien, Mohamed Manaa","doi":"10.2118/193223-MS","DOIUrl":"https://doi.org/10.2118/193223-MS","url":null,"abstract":"\u0000 Perforating a gas well efficiently requires applying technological advances to carry out a safe operation without compromising well productivity.\u0000 In this paper, is discussed the application of a pre- job plan methodology called perforating well on paper to the perforation operation of SITRA 3-4.\u0000 This methodology involved tension simulation, perforating gun and charge selection, conveyance hardware optimization, best underbalance value selection, as well as modeling of gun shock, gun movement and reservoir behavior when shooting multiple zones with different pressure regimes. Simulation methodology was performed as well real time during the perforating job to optimize static and flowing underbalance without compromising the safety of the operation and maximizing production gains.","PeriodicalId":11079,"journal":{"name":"Day 4 Thu, November 15, 2018","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75999121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Proactive Application of Human Performance Science in Risk Assessment Process within Dynamic Operations of an Oilfield Service Provider","authors":"A. Yasseen, S. Peresypkin","doi":"10.2118/193082-MS","DOIUrl":"https://doi.org/10.2118/193082-MS","url":null,"abstract":"\u0000 Human performance principles, which are well developed in aviation and healthcare, still represent an emerging science within the oil and gas industry. The industry managed to significantly reduce injuries over the last decade with multiple programs ranging from HSE Leadership to Behavior-Based Safety to the point when the incidents plateaued according to IOGP and IADC incident statistics. This triggered a deeper look into human performance best practices and their applicability within the oil and gas sector. This paper aims to provide an alternative approach to adopt Human Performance science to the dynamic operations risk assessment process within an Oilfield Services Company. After the analysis of the existing human reliability assessment tools, a decision was made to adopt a human performance tool known as Human Error Assessment & Reduction Technique (HEART) into a service provider’s risk assessment process with a primary focus on Error Producing Conditions (EPC). An internal survey was undertaken to define Error Producint Condition, which are most relevant to the dynamic nature of oil and gas services operations and couple them with the Reasons’s performance modes and their effect on error appearance. This approach allowed to significantly simplify the risk assessment process and adequately focus on key factors known to produce conditions for human error. This naturally integrated into our existing qualitative risk assessment to recalculate the overall risk of a certain task and enhanced workers’ ability to recognize potentially dangerous external and internal factors.\u0000 The field tests of the improved human performance risk assessments reshaped the standard risk assessment practices, moving the focus to and targeting the inherent unreliability of the task as a result of error producing conditions caused by unavoidable human interactions within the complex systems. This approach proved effective in improving the overall understanding of dynamic human reliability related risks among the front line employees by around 30%. The hypothesis is that by introducing key human performance factors to the day-to-day risk assessment will help build awareness of human factors and their relationship to the probability of an existing risk. At the same time, utilizing an already effective system – risk assessment – to introduce human factors methods will help avoid the complexity associated with its implementation of an additional human reliability tool and still get the benefit of key elements of a well-established method.\u0000 This approach has undertaken to combine two existing effective systems: a standard risk assessment with integrated human factors under a customized umbrella fully suitable for Oilfield Service Company’s work specifics. This paper provides insights on how human factors can impact the level of risk and outlines the control measures targeted at such factors that can be missed if a standard risk assessment is applied.","PeriodicalId":11079,"journal":{"name":"Day 4 Thu, November 15, 2018","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80903759","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Step Changes in Deep, Open-Water Riserless Coiled Tubing Operations","authors":"J. Stuker, J. Campos, D. Morbelli, J. Rivas, E. F. Delgado, Joao Assis","doi":"10.2118/193090-MS","DOIUrl":"https://doi.org/10.2118/193090-MS","url":null,"abstract":"\u0000 Scale buildup due to water production can choke oil production and require repetitive scale treatments across entire fields. In subsea wells, the common solution employs a deepwater rig to conduct either workover operations or large-volume scale inhibitor squeezes. Less frequently, coiled tubing (CT) is used from a moonpool vessel. However, current oil prices required a custom solution for subsea well treatments that was more cost effective than either a rig or a moonpool vessel.\u0000 Similar previous operations successfully used 1 ¾-in. and 2-in. (44.4 mm. and 50 mm.) CT at the same time from a moonpool vessel. A remotely operated vehicle (ROV) in the open water connected the CT to the subsea safety module (SSM) through a dynamic conduit and connected the SSM to the wellhead. An engineered solution to change to 2 7/8-in. CT and use high-rate stimulation pumps was planned to deliver subsea treatments at up to 15 bbl/min. The equipment layout was designed for a multipurpose supply vessel with chemical storage tanks; to increase the available selection of vessels, the CT was designed to run overboard rather than through a moonpool.\u0000 This project was initiated after accelerated scale buildup occurred because of a pressure decrease close to the bubble point, which happened when the drawdown was increased for aggressive production targets. To effectively inhibit scale in this environment, treatments required thousands of barrels of inhibitor. For wells with more-severe scale conditions, acid treatments were planned. These treatments were delivered with one complete CT package, stimulation pumping fleet, and subsea equipment, which were all installed on the spare deck space of the available vessel.\u0000 A custom overboard CT deployment tower was designed. The new tower improved the dynamic bend stiffener (DBS) placement, which allowed the clump weights to be deployed with the bottomhole assembly (BHA) and simplified the rig-up. The chosen vessel worked well for the operation; however, the equipment layout and the local weather conditions combined with the response amplitude operator (RAO) of the vessel shortened the projected fatigue life of the CT.\u0000 CT integrity monitoring with magnetic flux leakage (MFL) measurement was introduced here, and the vessel’s motion reference unit (MRU) provided an input to a fatigue calculator, based on the global riser analysis (GRA). The measurements and the analysis were utilized successfully to prevent CT pipe failures in the open water and deliver the required well treatments. To allow further improvements in deepwater operations, the new engineering work-flow was carefully documented.","PeriodicalId":11079,"journal":{"name":"Day 4 Thu, November 15, 2018","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89939107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal Degradation Kinetics of Epoxy Resins and Their Drilling Application","authors":"A. Al-Yami, V. Wagle, W. Jimenez, P. Jones","doi":"10.2118/192863-MS","DOIUrl":"https://doi.org/10.2118/192863-MS","url":null,"abstract":"\u0000 Epoxy-resin applications in oil and gas wells have significantly increased for remediation and sustained-casing-pressure mitigation because of its solids-free nature and excellent thermomechanical/bonding properties when used either as a single component or as a resin/cement-enhanced composite. Therefore, it is imperative to assess the formation and degradation of structures in cured epoxy resin at downhole temperatures, particularly because hydrocarbon production requires long-term wellbore integrity.\u0000 Differential scanning calorimetry (DSC) was used to determine the glass transition temperature (Tg) of the proposed resin system, and thermogravimetric analysis (TGA) was used to characterize the thermal degradation response by monitoring the resin specimens’ mass loss over time under controlled temperatures ranging from 300 to 680°F at atmospheric pressure. The thermal kinetic response based on TGA was then modeled using the Arrhenius equation to predict the resin lifetime under expected wellbore conditions. A uniaxial load frame Tinius Olsen tester was used to assess the mechanical response of the resin system under elevated temperatures.\u0000 For a resin system subjected to downhole temperatures of 263°F, the model predicts that reaching 10% mass loss by thermal degradation can take more than 160 years, which is beyond the operational life of the wells where the system is evaluated. This indicates that the investigated resin system provides long-term dependability that ultimately results in reduction of intervention/remediation costs, along with production maximization. Additionally, the resin mechanical properties were evaluated at different temperatures to assess their response to expected thermal loading, which resulted in competent barriers that can withstand the cyclic loads generated by continuous wellbore operations. This work also presents a case study in which an epoxy-resin-cement composite is used as an annular barricade to help prevent and reduce sustained casing pressure. The resin-cement composite was placed in the annular section as a chemical packer tailored to improve bonding to steel pipe, along with optimizing its mechanical response to cyclic downhole loads, which resulted in no up-to-date sustained casing pressure. Furthermore, Cement Bond Log (CBL) results further support the optimum annular integrity attained when utilizing a cement-resin composite as chemical packer for enhanced isolation and annular pressure buildup mitigation.","PeriodicalId":11079,"journal":{"name":"Day 4 Thu, November 15, 2018","volume":"53 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75283536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improve Operator Effectiveness to Facilitate Effective Collaboration","authors":"Livin Vincent Thalakkottur, Subhankar Dey","doi":"10.2118/193297-MS","DOIUrl":"https://doi.org/10.2118/193297-MS","url":null,"abstract":"\u0000 The paper reviews how traditional control room designs, automation & controls and operational practices have become obsolete. With demand and supply fluctuations in the region, operating teams often find it challenging to achieve organization goals and production targets. And although the control room infrastructure may go through upgrades, situational awareness often is not improved. Today's world is at haste to achieve results, frequently compromising quality. The truth is that there are unhappy stakeholders whose operating environment doesn't meet their expectations.\u0000 Today, with advanced technology and human-factors engineering, control rooms can be better designed to improve operator effectiveness. In general, this enables various stakeholders to make better decisions, faster. This text reviews how operator effectiveness and collaboration is improved by carrying out interactive brain storming sessions to understand user requirements, manage competency, apply management of change, analyze complexity in various roles and evaluate human machine interface, console & control room designs. Benchmark studies expose the gaps and direct the user's attention to actions needed to achieve best results. In addition, the authors discuss how smart collaboration can be applied to prototype tests and virtual Factory Acceptance Tests.\u0000 The authors note that middle-eastern culture for operator effectiveness and collaboration is a bit laid-back when compared to competitors in the global market. However, the outcome of the methods described in this paper, when applied to an organization driven by leadership, secured better results. This paper reviews similar methods adopted by organizations which experienced greater Return-On-Investment. Moreover, market fluctuations increase the need to optimize and standardize processes to aid faster and smarter collaboration.","PeriodicalId":11079,"journal":{"name":"Day 4 Thu, November 15, 2018","volume":"349 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79730024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated Geo-Modeling and Ensemble History Matching of Complex Fractured Carbonate and Deep Offshore Turbidite Fields, Generation of Several Geologically Coherent Solutions Using Ensemble Methods","authors":"A. Abadpour, Moyosore Adejare, T. Chugunova, H. Mathieu, N. Haller","doi":"10.2118/193028-MS","DOIUrl":"https://doi.org/10.2118/193028-MS","url":null,"abstract":"\u0000 History matching reservoir models has always been tedious as it involves many uncertain parameters and requires many trial and error iterations. Frequently the modifications introduced seem artificial and may destroy geological concepts, only one matched model is obtained and the forecast of such a model may quickly be invalidated by new data. Eventually imperfect models lead to imperfect decisions.\u0000 Assisted History matching with ensemble methods has received a lot of attention in the past decade. In this methodology with an ensemble of models the correlation between all uncertain model parameters and the selected production data is assessed and using this correlation the ensemble of the models are modified to reduce the difference between simulated and real historical data in an iterative manner.\u0000 Ensemble methods are recognized to perfectly perform on the continuous Gaussian parameters, but their application on discrete geological parameters like facies and rock types has been a challenge for several years. Different solutions proposed to tackle this issue showed the importance of integrated workflows and the implementation of an assisted history matching loop in close relationship with the geo-modeling tools.\u0000 After several years of research, an assisted history matching tool based on ensemble method has been developed in Total via the integrated platform of geo-modelling Sismage-CIG. This tool has been industrialized early 2016 with the first operational study performed on a giant gas field in the Middle-East.\u0000 Ensemble methods are known to be relatively insensitive to the size of the model, number of uncertain parameters to be handled, number of wells and the length of historical data, but the industrialization of the tool to operate on huge complex fields with very large number of the wells needed several rounds of code optimization using state of art algorithmic approaches.\u0000 This tool showed outstanding performance on several types of models such as turbiditic deep-offshore and complex fractured carbonate fields. The latest history matching study performed with this method on a Middle-East field modeled with a grid containing 20 million cells, around 200 wells and more than 25 years of production history, involved more than 130 million uncertain parameters in each realization.\u0000 The use of assisted history matching with ensemble methods allows not only to take into account cell by cell heterogeneities as uncertainty in a coherent manner but it also delivers an ensemble of hundred matched models which creates a huge opportunity for forecast and decision making process. Moreover all models fully respect the geological a priori knowledge and the duration of history matching study has been drastically reduced (weeks instead of months if not years) using much less manpower.","PeriodicalId":11079,"journal":{"name":"Day 4 Thu, November 15, 2018","volume":"16 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82068299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Considerations of Pipeline Crossing Design","authors":"Abdul Rahman El-Chayeb, D. Wang, F. Kamal, Oussama Takieddine","doi":"10.2118/192652-MS","DOIUrl":"https://doi.org/10.2118/192652-MS","url":null,"abstract":"\u0000 Pipeline crossings are an integral part of brown field developments and their design for shallow water conditions poses a number of challenges which require special considerations. Hydrodynamic stability and Vortex Induced Vibration (VIV) are typical examples. For both of these design aspects, there is no specific design criteria and methodologies dealing with crossings as is the case for pipelines resting of the seabed which, among other codes and standards, are covered by DNVGL RP F109 and DNVGL RP F105 for stability and VIV respectively. In the absence of specific design criteria, the industry have relied on interpretations of existing codes leading to crossing designs with varying failure probabilities and safety levels for different projects and different operators.\u0000 This paper discusses the main aspects of pipeline crossing design in shallow water conditions as is the case for the Arabian Gulf Region. In this region, the water depths could be close to the limits of applicability of the conventional design codes which were established based on experiences and considerations for other geographical regions. As a result, the design of crossings poses an engineering challenge as the calculated allowable span lengths tends to be short and the number of supports greater than what can be reasonably constructed for the pipeline to sit on all supports. The viability of using design criteria adapted from these codes for VIV is assessed using full dynamic simulations taking into account the compressive axial loads in the crossing. It is shown that for the short crossing spans, which are typical in the shallow water of the gulf region, the onset of any VIV will result in phenomenon which is called here \"crosswalking\". This crosswalking will result in a lateral displacement of the pipeline over the crossing sleepers resulting in an increase in the first natural frequency due to the reduction in axial compressive loads and the change in behavior from beam to shallow arch.\u0000 Implementing the analysis procedure discussed in this paper and taking into account the potential for crosswalking will help increase the length of the crossing spans. This increase can be to a level where the hyperstatic conditions can be eliminated and the crossings can be designed to be construction friendly. This will have direct cost and schedule impact on the execution of brown field developments where crossings constitute a major element of the project. It is hoped that further work will be done on studying the VIV of pipeline spans and crossings under axial compression as this area of pipeline engineering has not been fully explored and the focus of VIV research has been directed to risers which are always under axial tension.","PeriodicalId":11079,"journal":{"name":"Day 4 Thu, November 15, 2018","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82307126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development and Testing of an LWD Ultrasonic Microimaging Tool: Field Test Results from the Middle East and Europe","authors":"G. Warot, Shawn Wallace, H. Mostafa, Eslam Elabsy, Davide Di Tommaso, Aly Abdelkarim, C. Ciuperca","doi":"10.2118/193055-MS","DOIUrl":"https://doi.org/10.2118/193055-MS","url":null,"abstract":"\u0000 Increased development of naturally and hydraulically fractured unconventional reservoirs from horizontal wells, drilled with oil-based muds, has created a need for high-resolution logging-while-drilling (LWD) borehole imaging tools capable of resolving fractures in this borehole environment. A new LWD ultrasonic borehole imager has been developed and tested to meet this need.\u0000 Borrowing from wireline ultrasonic imaging technology, a 250 kHz piezo-electric transducer was adapted to an LWD drill collar. The single transducer serves as both transmitter and receiver: transmitting an ultrasonic pulse, and measuring both the amplitude and two-way travel time of the acoustic reflection from the borehole wall. The LWD tool takes advantage of drill string rotation making a 360-degree scan of the borehole with a single fixed transducer. Finite element modeling and laboratory testing in artificial formations and a large limestone block were used to determine the spatial resolution of the image, as well as the sensitivity to downhole acquisition variables such as standoff, tool eccentricity, and mud attenuation. Prototype tools were then field tested in several horizontal wells to verify the functionality and image resolution under actual drilling conditions.\u0000 The borehole images from horizontal wells in unconventional and conventional reservoirs in the Middle East and the UK verified that tool responded as designed. These images, recorded in both oil-based and water based muds, revealed open and cemented natural fractures, drilling induced fractures and borehole breakout, fine-scale bedding, and other textural geological features such as vugs and stylolites. A variety of drilling-related borehole artifacts were also observed, including keyseats, stabilizer impressions in the borehole wall, tool marks from a rotary steerable tool, and gouges made by the bit rotating off bottom. The amplitude image proved more sensitive to fractures, bedding, and other geological features, while the travel time image, combined with input mud compressional velocity, provided a 360-degree borehole caliper image, showing the borehole size and shape.\u0000 Although high-resolution LWD electrical imagers have been available for years, these can only operate in conductive, water-based, muds. As most horizontal wells in both conventional and unconventional reservoirs are now drilled with oil-based muds, the development of a high-resolution ultrasonic imager capable of identifying natural and hydraulic fractures, fine-scale bedding, secondary porosity, and other small scale features in wells drilled with oil-based muds fills an important gap in LWD technology.","PeriodicalId":11079,"journal":{"name":"Day 4 Thu, November 15, 2018","volume":"13 2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81239557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Diffusion Coefficient and Fracture Aperture in Coal using Micro-Computed Tomography Imaging","authors":"Xiao Lu, R. Armstrong, Meng Yuan, Yulai Zhang, P. Mostaghimi","doi":"10.2118/193003-MS","DOIUrl":"https://doi.org/10.2118/193003-MS","url":null,"abstract":"\u0000 Coalbed methane (CBM), also known as coal seam gas, is becoming an increasingly important energy resource in the global natural gas market. Gas transport in CBM reservoirs remains a crucial research topic that has not been fully understood. Two scales of gas flow are identified in coal cores: flow in fractures and diffusion within matrix. The diffusion process is quantified by the gas diffusion coefficient while flow in fractures is governed by fracture apertures. This paper aims to explore the diffusion process in coal using X-ray microcomputed tomography (micro-CT) imaging. The experiments are conducted at 100 psi effective stress to eliminate the impact of pressure. The images obtained are registered for visualisation and analysis of the diffusion process and comparisons of fracture. In the paper, the impact of increasing effective stress on fracture aperture is demonstrated. Also, the diffusion coefficient of Krypton in coal matrix is estimated and discussed.","PeriodicalId":11079,"journal":{"name":"Day 4 Thu, November 15, 2018","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77688013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}