Download or read book TIME LAPSE SEISMIC MODELING INVERSION OF CO2 SATURATION FOR SEQUESTRATION AND ENHANCED OIL RECOVERY written by Mark A. Meadows and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Injection of carbon dioxide (CO2) into subsurface aquifers for geologic storage/sequestration, and into subsurface hydrocarbon reservoirs for enhanced oil recovery, has become an important topic to the nation because of growing concerns related to global warming and energy security. In this project we developed new ways to predict and quantify the effects of CO2 on seismic data recorded over porous reservoir/aquifer rock systems. This effort involved the research and development of new technology to: (1) Quantitatively model the rock physics effects of CO2 injection in porous saline and oil/brine reservoirs (both miscible and immiscible). (2) Quantitatively model the seismic response to CO2 injection (both miscible and immiscible) from well logs (1D). (3) Perform quantitative inversions of time-lapse 4D seismic data to estimate injected CO2 distributions within subsurface reservoirs and aquifers. This work has resulted in an improved ability to remotely monitor the injected CO2 for safe storage and enhanced hydrocarbon recovery, predict the effects of CO2 on time-lapse seismic data, and estimate injected CO2 saturation distributions in subsurface aquifers/reservoirs. We applied our inversion methodology to a 3D time-lapse seismic dataset from the Sleipner CO2 sequestration project, Norwegian North Sea. We measured changes in the seismic amplitude and traveltime at the top of the Sleipner sandstone reservoir and used these time-lapse seismic attributes in the inversion. Maps of CO2 thickness and its standard deviation were generated for the topmost layer. From this information, we estimated that 7.4% of the total CO2 injected over a five-year period had reached the top of the reservoir. This inversion approach could also be applied to the remaining levels within the anomalous zone to obtain an estimate of the total CO2 injected.

Download or read book TIME LAPSE MODELING AND INVERSION OF CO2 SATURATION FOR SEQUESTRATION AND ENHANCED OIL RECOVERY written by Mark A. Meadows and published by . This book was released on 2004 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the fourth quarter of this DOE NETL project, they have developed an algorithm for generating time-lapse seismic anomalies from changes in fluid properties over time. This forward-modeling algorithm constitutes the first step in the inversion procedure of Phase III of the project. Examples were generated illustrating the flexibility of this approach. Additional activities in this reporting period included a trip by the Principal Investigator to the 7th International Conference on Greenhouse Gas Control Technologies (GHGT-7) in Vancouver, Canada, September 5-9, 2004. In the next quarter, they will work on the second step of the inversion procedure, namely, the inversion of the seismic time-lapse anomalies to obtain changes in fluid properties, and will continue investigating alternative methods for calculating properties of oil/brine/CO{sub 2} and brine/CO{sub 2} systems.

Download or read book TIME LAPSE MODELING AND INVERSION OF CO2 SATURATION FOR SEQUESTRATION AND ENHANCED OIL RECOVERY written by and published by . This book was released on 2005 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the fifth quarter of this DOE NETL project, they have implemented an algorithm that inverts for changes in fluid properties over time using time-lapse seismic anomalies. This algorithm constitutes the second step in the inversion procedure for Phase III of the project. They demonstrate this inversion procedure with a synthetic data example. Additional activities in this reporting period include a trip by the Principal investigator to an International Monitoring Workshop sponsored by the IEA Greenhouse Gas R and D Program in Santa Cruz, California. In the next quarter, they will further process the Sleipner data to prepare it for later inversion, and continue investigating alternative methods for calculating properties of oil/brine/CO2 systems.

Download or read book Integrated Reservoir Studies for CO2 Enhanced Oil Recovery and Sequestration written by Shib Sankar Ganguli and published by Springer. This book was released on 2017-03-30 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses the feasibility of CO2-EOR and sequestration in a mature Indian oil field, pursuing for the first time a cross-disciplinary approach that combines the results from reservoir modeling and flow simulation, rock physics modeling, geomechanics, and time-lapse (4D) seismic monitoring study. The key findings presented indicate that the field under study holds great potential for enhanced oil recovery (EOR) and subsequent CO2 storage. Experts around the globe argue that storing CO2 by means of enhanced oil recovery (EOR) could support climate change mitigation by reducing the amount of CO2 emissions in the atmosphere by ca. 20%. CO2-EOR and sequestration is a cutting-edge and emerging field of research in India, and there is an urgent need to assess Indian hydrocarbon reservoirs for the feasibility of CO2-EOR and storage. Combining the fundamentals of the technique with concrete examples, the book is essential reading for all researchers, students and oil & gas professionals who want to fully understand CO2-EOR and its geologic sequestration process in mature oil fields.

Download or read book Time lapse Seismic Modeling and Production Data Assimilation for Enhanced Oil Recovery and CO2 Sequestration written by Ajitabh Kumar and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Production from a hydrocarbon reservoir is typically supported by water or carbon dioxide (CO2) injection. CO2 injection into hydrocarbon reservoirs is also a promising solution for reducing environmental hazards from the release of green house gases into the earth0́9s atmosphere. Numerical simulators are used for designing and predicting the complex behavior of systems under such scenarios. Two key steps in such studies are forward modeling for performance prediction based on simulation studies using reservoir models and inverse modeling for updating reservoir models using the data collected from field. The viability of time-lapse seismic monitoring using an integrated modeling of fluid flow, including chemical reactions, and seismic response is examined. A comprehensive simulation of the gas injection process accounting for the phase behavior of CO2-reservoir fluids, the associated precipitation/dissolution reactions, and the accompanying changes in porosity and permeability is performed. The simulation results are then used to model the changes in seismic response with time. The general observation is that gas injection decreases bulk density and wave velocity of the host rock system. Another key topic covered in this work is the data assimilation study for hydrocarbon reservoirs using Ensemble Kalman Filter (EnKF). Some critical issues related to EnKF based history matching are explored, primarily for a large field with substantial production history. A novel and efficient approach based on spectral clustering to select 0́optimal0́9 initial ensemble members is proposed. Also, well-specific black-oil or compositional streamline trajectories are used for covariance localization. Approach is applied to the Weyburn field, a large carbonate reservoir in Canada. The approach for optimal member selection is found to be effective in reducing the ensemble size which was critical for this large-scale field application. Streamline-based covariance localization is shown to play a very important role by removing spurious covariances between any well and far-off cell permeabilities. Finally, time-lapse seismic study is done for the Weyburn field. Sensitivity of various bulk seismic parameters viz velocity and impedance is calculated with respect to different simulation parameters. Results show large correlation between porosity and seismic parameters. Bulk seismic parameters are sensitive to net overburden pressure at its low values. Time-lapse changes in pore-pressure lead to changes in bulk parameters like velocity and impedance.

Download or read book Time lapse Seismic Modeling for CO2 Sequestration at the Dickman Field Kansas written by Jintan Li and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Time-lapse seismic modeling is often used to study hydrocarbon reservoirs, especially for those undergoing injection or production. The Dickman field, Kansas, provides two possible CO2 sequestration targets: a regional deep saline reservoir (the primary objective) and a shallower mature, depleted oil reservoir (secondary). The work in this dissertation characterizes and simulates monitoring of CO2 movement before, during, and after injection including fluid flow paths, reservoir property changes, CO2 containment, and post-injection stability. My seismic simulation for time-lapse CO2 monitoring was based on flow simulator output over a 50-year injection and 250-year simulation period. This work introduces a feasible and reliable regridding technique that resolves different scales from geological modeling, flow simulation, to seismic modeling for a realistic carbonate geological model. Gassmann fluid substitution theory is applied to calculate fluid properties changes before and after injection. For a porous Mississippian carbonate reservoir with average 25% porosity, the P wave velocity can change around 15% with CO2 saturation up to 84%. Seismic simulation was accomplished via PP and PS reflectivity from the Zoeppritz equation, convolutional (1D), acoustic and elastic (2D) finite difference modeling by a flux-corrected transport equation. This work assesses the effectiveness of 4D seismic monitoring in the evaluation of long-term CO2 containment stability through a fault leakage test. A CO2 plume can be detected from the difference on seismic sections with 5 to 10ms time shift at the storage site before and after injection, and was validated by comparison with the prestack field data. Time-lapse flow to seismic modeling is proved to be useful for carbon dioxide sequestration in a hard rock carbonate reservoir.

Download or read book Time lapse Seismic Monitoring for Enhanced Oil Recovery and Carbon Capture and Storage Field Site at the Cranfield Field Mississippi written by Julie Nicole Ditkof and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cranfield field, located in southwest Mississippi, is an enhanced oil recovery and carbon sequestration project that has been under a continuous supercritical CO2 injection by Denbury Onshore LLC since 2008. Two 3D seismic surveys were collected in 2007, pre-CO2 injection, and in 2010 after > 2 million tons of CO2 was injected into the subsurface. The goal of this study is to characterize a time-lapse response between two seismic surveys to understand where injected CO2 is migrating and to map the injected CO2 plume edge. In order to characterize a time-lapse response, the seismic surveys were cross equalized using a trace-by-trace time shift. A normalized root-mean-square (NRMS) difference value was then calculated to determine the repeatability of the data. The data were considered to have "good repeatability," so a difference volume was calculated and showed a coherent seismic amplitude anomaly located through the area of interest. A coherent seismic amplitude anomaly was also present below the area of interest, so a time delay analysis was performed and calculated a significant added velocity change. A Gassmann-Wood fluid substitution workflow was then performed at two well locations to predict a saturation profile and observe post-injection expected changes in compressional velocity values at variable CO2 saturations. Finally, acoustic impedance inversions were performed on the two seismic surveys and an acoustic impedance difference volume was calculated to compare with the fluid substitution results. The Gassmann-Wood fluid substitution results predicted smaller changes in acoustic impedance than those observed from acoustic impedance inversions. At the Cranfield field, time-lapse seismic analysis was successful in mapping and quantifying the acoustic impedance change for some seismic amplitude anomalies associated with injected CO2. Additional well log data and refinement of the fluid substitution workflow and the model-based inversion performed is necessary to obtain more accurate impedance changes throughout the field instead of at a single well location.

Download or read book CO2 Sequestration and Valorization written by Claudia R. V. Morgado and published by BoD – Books on Demand. This book was released on 2014-03-12 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reconciliation of economic development, social justice and reduction of greenhouse gas emissions is one of the biggest political challenges of the moment. Strategies for mitigating CO2 emissions on a large scale using sequestration, storage and carbon technologies are priorities on the agendas of research centres and governments. Research on carbon sequestration is the path to solving major sustainability problems of this century a complex issue that requires a scientific approach and multidisciplinary and interdisciplinary technology, plus a collaborative policy among nations. Thus, this challenge makes this book an important source of information for researchers, policymakers and anyone with an inquiring mind on this subject.

Download or read book Integrated Reservoir Studies for CO2 Enhanced Oil Recovery and Sequestration written by Shib Sankar Ganguli and published by Springer. This book was released on 2018-07-25 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses the feasibility of CO2-EOR and sequestration in a mature Indian oil field, pursuing for the first time a cross-disciplinary approach that combines the results from reservoir modeling and flow simulation, rock physics modeling, geomechanics, and time-lapse (4D) seismic monitoring study. The key findings presented indicate that the field under study holds great potential for enhanced oil recovery (EOR) and subsequent CO2 storage. Experts around the globe argue that storing CO2 by means of enhanced oil recovery (EOR) could support climate change mitigation by reducing the amount of CO2 emissions in the atmosphere by ca. 20%. CO2-EOR and sequestration is a cutting-edge and emerging field of research in India, and there is an urgent need to assess Indian hydrocarbon reservoirs for the feasibility of CO2-EOR and storage. Combining the fundamentals of the technique with concrete examples, the book is essential reading for all researchers, students and oil & gas professionals who want to fully understand CO2-EOR and its geologic sequestration process in mature oil fields.

Download or read book Application of Time Lapse Seismic Monitoring for the Control and Optimization of CO2 Enhanced Oil Recovery Operations written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This project, 'Application of Time-Lapse Seismic Monitoring for the Control and Optimization of CO2 Enhanced Oil Recovery Operations', investigated the potential for monitoring CO2 floods in carbonate reservoirs through the use of standard p-wave seismic data. This primarily involved the use of 4D seismic (time lapse seismic) in an attempt to observe and map the movement of the injected CO2 through a carbonate reservoir. The differences between certain seismic attributes, such as amplitude, were used for this purpose. This technique has recently been shown to be effective in CO2 monitoring in Enhanced Oil Recovery (EOR) projects, such as Weyborne. This study was conducted in the Charlton 30/31 field in the northern Michigan Basin, which is a Silurian pinnacle reef that completed its primary production in 1997 and was scheduled for enhanced oil recovery using injected CO2. Prior to injection an initial 'Base' 3D survey was obtained over the field and was then processed and interpreted. CO2 injection within the main portion of the reef was conducted intermittently during 13 months starting in August 2005. During this time, 29,000 tons of CO2 was injected into the Guelph formation, historically known as the Niagaran Brown formation. By September 2006, the reservoir pressure within the reef had risen to approximately 2000 lbs and oil and water production from the one producing well within the field had increased significantly. The determination of the reservoir's porosity distribution, a critical aspect of reservoir characterization and simulation, proved to be a significant portion of this project. In order to relate the differences observed between the seismic attributes seen on the multiple 3D seismic surveys and the actual location of the CO2, a predictive reservoir simulation model was developed based on seismic attributes obtained from the base 3D seismic survey and available well data. This simulation predicted that the CO2 injected into the reef would remain in the northern portion of the field. Two new wells, the State Charlton 4-30 and the Larsen 3-31, were drilled into the field in 2006 and 2008 respectively and supported this assessment. A second (or 'Monitor') 3D seismic survey was acquired during September 2007 over most of the field and duplicated the first (Base) survey, as much as possible. However, as the simulation and new well data available at that time indicated that the CO2 was concentrated in the northern portion of the field, the second seismic survey was not acquired over the extreme southern end of the area covered by the original (or Base) 3D survey. Basic processing was performed on the second 3D seismic survey and, finally, 4D processing methods were applied to both the Base and the Monitor surveys. In addition to this 3D data, a shear wave seismic data set was obtained at the same time. Interpretation of the 4D seismic data indicated that a significant amplitude change, not attributable to differences in acquisition or processing, existed at the locations within the reef predicted by the reservoir simulation. The reservoir simulation was based on the porosity distribution obtained from seismic attributes from the Base 3D survey. Using this validated reservoir simulation the location of oil within the reef at the time the Monitor survey was obtained and recommendations made for the drilling of additional EOR wells. The economic impact of this project has been estimated in terms of both enhanced oil recovery and CO2 sequestration potential. In the northern Michigan Basin alone, the Niagaran reef play is comprised of over 700 Niagaran reefs with reservoirs already depleted by primary production. Potentially there is over 1 billion bbls of oil (original oil in place minus primary recovery) remains in the reefs in Michigan, much of which could be more efficiently mobilized utilizing techniques similar to those employed in this study.

Download or read book Practical Applications of Time lapse Seismic Data written by David H. Johnston and published by SEG Books. This book was released on 2013 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Time-lapse (4D) seismic technology is a key enabler for improved hydrocarbon recovery and more cost-effective field operations. This book shows how 4D data are used for reservoir surveillance, add value to reservoir management, and provide valuable insight on dynamic reservoir properties such as fluid saturation, pressure, and temperature.

Download or read book Quantitative Monitoring of CO2 Injection at Sleipner Using Seismic Full Waveform Inversion in the Time Lapse Mode and Rock Physics Modeling written by Manuel Peter Queisser and published by . This book was released on 2011 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon capture and sequestration is a technology to achieve a considerable deceleration of CO2 emission promptly. Since 1996 one of the largest CO2 storage projects is taking place at Sleipner in the Norwegian North Sea. In order to monitor injected CO2, time lapse surface seismic monitoring surveys have been carried out. Estimating subsurface parameters from the Sleipner seismic data is a challenging problem due to the specific geology of the storage reservoir, which is further complicated by injected CO2. Most seismic imaging methods enable only qualitative insights into the subsurface. Full waveform inversion is well known in the seismic community but not well established yet. Presented results are mostly of demonstrative character. Applying full waveform inversion as an actual tool to a complex problem such as Sleipner is novel. Motivated by the need for a quantitative seismic monitoring of the injected CO2, I have applied 2D seismic full waveform inversion to seismic data sets from Sleipner from 1994 (baseline), 1999 and 2006 along three seismic lines to infer subsurface parameters and parameter changes in the storage reservoir. The P-wave velocity is the major parameter, as it is the most sensitive to CO2 injection. An energy preconditioning of the gradient has been implemented. The usual source wavelet calibration did not prove to be reliable. An alternative source calibration has been successfully applied. By comparing seismic images with inversion results, I found that using seismic images to locate CO2 accumulations in the subsurface may be misleading. The quantitative imaging approach using full waveform inversion resulted in a consistent evolution of the model parameter with time. Major reductions in Pwave velocity and hence the CO2 accumulations could be quantitatively imaged down to a resolution of 10 m. Observed travel time shifts due to CO2 injection are comparable to those derived from the inversion result. In order to estimate CO2 saturations, rock physical concepts have been combined and extended to arrive at a rock physical formulation of the subsurface at Sleipner. I used pseudo Monte Carlo rock physics modeling to assess the influence of lithologic heterogeneity on the CO2 saturations as well as to generate pseudo well logs to estimate confidence intervals of the inverted parameters. The rock physics modeling has been used to relate inverted parameters to CO2 saturations. The injected CO2 is buoyant. The highest CO2 saturations are in the upper half of the storage reservoir but not necessarily at the top. Non-uniqueness of the saturation maps associated with the density scenario has been assessed. As a result, the distribution of the maximum saturation values remains the same. The quantity of dissolved CO2 in the reservoir water is a key parameter from both a security and optimization point of view. A quantitative estimation of dissolved CO2 by seismic means has not been undertaken yet to our knowledge. Based on the seismic inversion result of a seismic line, I found that along the line at least 20% of the injected CO2 mass was dissolved in 2006, after 10 years of injection. Such a high value indicates enhanced solubility trapping, which is very advantageous for storage safety at Sleipner. The results of this work represent a further step towards ultimate goals of quantitative monitoring, such as the estimation of the injected CO2 in-situ volume.

Download or read book Numerical Modeling of Time lapse Seismic Data from Fractured Reservoirs Including Fluid Flow and Geochemical Processes written by Ravi Shekhar and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fractured reservoirs, especially in low permeable carbonate rocks, are important target for hydrocarbon exploration and production because fractures can control fluid flow inside the reservoir. Hence, quantitative knowledge of fracture attributes is important for optimal hydrocarbon production. However, in some cases fractures can cause leakage of injected CO2 during enhanced oil recovery (EOR) or CO2 sequestration. Furthermore, CO2 can geochemically interact with reservoir fluids and host rock. Hence, time-lapse monitoring of the progress of CO2 in fractured reservoirs is also very important. In order to address these challenges, I have developed an integrated approach for studying fluid flow and seismic wave propagation in fractured media using Discrete Fracture Network (DFN) models. My seismic simulation study suggests that CO2 saturated reservoir shows approximately ten times more attenuation than brine saturated reservoir. Similarly, large P-wave velocity variation in CO2 saturated reservoir and amplitude variation with offset (AVO) results for our example model predicts that CO2 is easier to detect than brine in the fractured reservoirs. The effects of geochemical processes on seismics are simulated by time-lapse modeling for t = 1000 years. My modeling study suggests that intra-aqueous reactions are more significant during injection of CO2 for t = 6 years, while slower mineral reactions dominate after pressure equilibrium is achieved that is from t = 6 to 1000 years. Overall both types of geochemical reactions cause change in reflection coefficient of 2 to 5%, which may be difficult to detect in some cases. However, the significant change in the seismic properties at the boundary of the CO2 front can be used to detect the flow path of CO2 inside the reservoirs. Finally, a method for generating stochastic fracture models was extended and improved to more realistic field model for seismic and fluid modeling. My detail analysis suggests that fractures generated by isotropic stress field favor orthogonal sets of fractures in most subsurface rocks that can be converted to seismic model, similar to DFN study. The quality and validity of the models is assessed by comparisons to DFN models, including calculations of fractal dimension measures that can help to characterize fractured reservoirs.

Download or read book Geophysics and Geosequestration written by Thomas L. Davis and published by Cambridge University Press. This book was released on 2019-05-09 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview of the geophysical techniques and analysis methods for monitoring subsurface carbon dioxide storage for researchers and industry practitioners.

Download or read book Seismic Reservoir Modeling written by Dario Grana and published by John Wiley & Sons. This book was released on 2021-05-04 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic reservoir characterization aims to build 3-dimensional models of rock and fluid properties, including elastic and petrophysical variables, to describe and monitor the state of the subsurface for hydrocarbon exploration and production and for CO2 sequestration. Rock physics modeling and seismic wave propagation theory provide a set of physical equations to predict the seismic response of subsurface rocks based on their elastic and petrophysical properties. However, the rock and fluid properties are generally unknown and surface geophysical measurements are often the only available data to constrain reservoir models far away from well control. Therefore, reservoir properties are generally estimated from geophysical data as a solution of an inverse problem, by combining rock physics and seismic models with inverse theory and geostatistical methods, in the context of the geological modeling of the subsurface. A probabilistic approach to the inverse problem provides the probability distribution of rock and fluid properties given the measured geophysical data and allows quantifying the uncertainty of the predicted results. The reservoir characterization problem includes both discrete properties, such as facies or rock types, and continuous properties, such as porosity, mineral volumes, fluid saturations, seismic velocities and density. Seismic Reservoir Modeling: Theory, Examples and Algorithms presents the main concepts and methods of seismic reservoir characterization. The book presents an overview of rock physics models that link the petrophysical properties to the elastic properties in porous rocks and a review of the most common geostatistical methods to interpolate and simulate multiple realizations of subsurface properties conditioned on a limited number of direct and indirect measurements based on spatial correlation models. The core of the book focuses on Bayesian inverse methods for the prediction of elastic petrophysical properties from seismic data using analytical and numerical statistical methods. The authors present basic and advanced methodologies of the current state of the art in seismic reservoir characterization and illustrate them through expository examples as well as real data applications to hydrocarbon reservoirs and CO2 sequestration studies.

Download or read book Application of Time Lapse Seismic Monitoring for the Control and Optimization of CO2 Enhanced Oil Recovery Operations written by Brian E. Toelle and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The ''Application of Time-Lapse Seismic Monitoring for the Control and Optimization of CO{sub 2} Enhanced Oil Recovery Operations'' project is investigating the potential for monitoring CO{sub 2} floods in carbonate reservoirs through the use of standard p-wave seismic data. This project will involve the use of 4D seismic (time lapse seismic) to try to observe the movement of the injected CO{sub 2} through the reservoir. The differences between certain seismic attributes, such as amplitude, will be used to detect and map the movement of CO{sub 2} within the reservoir. This technique has recently been shown to be effective in CO{sub 2} monitoring in EOR projects such as Weyborne. The project is being conducted in the Charlton 30/31 field in northern Michigan Basin which is a Silurian pinnacle reef that has completed its primary production. This field is now undergoing enhanced oil recovery using CO{sub 2}. The CO{sub 2} flood was initiated the end of 2005 when the injection of small amounts of CO{sub 2} begin in the A1 Carbonate. This injection was conducted for 2 months before being temporarily halted in order for pressure measurements to be conducted. The determination of the reservoir's porosity distribution is proving to be a significant portion of this project. In order to relate the differences observed between the seismic attributes seen on the multiple surveys and the actual location of the CO{sub 2}, a predictive reservoir simulation model had to be developed. From this model, an accurate determination of porosity within the carbonate reservoir must be obtained. For this certain seismic attributes have been investigated. The study reservoirs in the Charlton 30/31 field range from 50 to 400 acres in size. The relatively small area to image makes 3-D seismic data acquisition reasonably cost effective. Permeability and porosity vary considerably throughout the reef, thus it is essential to perform significant reservoir characterization and modeling prior to implementing a CO{sub 2} flood to maximize recovery efficiency. Should this project prove successful, the same technique could be applied across a large spectrum of the industry. In Michigan alone, the Niagaran reef play is comprised of over 700 Niagaran reefs with reservoirs already depleted by primary production. These reservoirs range in thickness from 200 to 400 ft and are at depths of 2000 to 5000 ft. Approximately 113 of these Niagaran oil fields have produced over 1 million bbls each and the total cumulative production is in excess of 300 million bbls and 1.4 Tcf. There could potentially be over 1 billion bbls of oil remaining in reefs in Michigan much of which could be mobilized utilizing techniques similar to those employed in this study.

Download or read book Carbon Sequestration Monitoring with Acoustic Double difference Waveform Inversion written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Geological carbon sequestration involves large-scale injection of carbon dioxide into underground geologic formations and is considered as a potential approach for mitigating global warming. Changes in reservoir properties resulting from the CO2 injection and migration can be characterized using waveform inversions of time-lapse seismic data. The conventional approach for analysis using waveform tomography is to take the difference of the images obtained using baseline and subsequent time-lapse datasets that are inverted independently. By contrast, double-difference waveform inversion uses timelapse seismic datasets to jointly invert for reservoir changes. We apply this method to a field time-lapse walkaway VSP data set acquired in 2008 and 2009 for monitoring CO2 injection at an enhanced oil recovery field at SACROC, Texas. The double-difference waveform inversion gives a cleaner and more easily interpreted image of reservoir changes, as compared to that obtained with the conventional scheme. Our results from the applicatoin of acoustic double-difference waveform tomography shows some zones with decreased P-wave velocity within the reservoir due to CO2 injection and migration.