Download or read book A Reduced order Basis Approach for CO2 Monitoring from Sparse Time lapse Seismic Data written by Badr Waleed A Alrumaih and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: I present an approach for seismic monitoring from sparse time-lapse data, with a particular focus on leak detection from CO2 storage reservoirs. I use sparse data because it is (1) faster and (2) less expensive to acquire and to process, permitting for more frequent monitoring surveys to be carried out. This would allow for (1) early leak detection, which is what we ultimately aim for at a storage site, and (2) timely assessment of performance conformance. To account for data sparsity, I incorporate information on the underlying (injection) process (pressure and flow) into the geophysical model estimation. By process information, I mean how the geophysical model is possibly or potentially perturbed due to CO2 injection, as governed by the physics of the flow and the rock properties model. I do that by reformulating the geophysical minimization problem with Reduced-Order Basis (ROB) functions that are derived from simulated training images stochastically describing how the geophysical model is perturbed by the CO2 injection including leak possibilities, which I will refer to as ROB-inversion. Naturally, reducing the spatial sampling of the acquired data leads to reduced spatial resolution of the reconstructed subsurface model. This is the tradeoff for the increased calendar-time resolution, i.e., the shorter monitoring calendar-time interval. By reformulating the geophysical minimization problem with the process-derived reduced-order basis functions, I can improve the spatial resolution of the subsurface model—leading to approximate (or reduced-order) models. The accuracy of the reduced-order models depends on how representative the training image set is to the true model change. A key point in my implementation is the formulation of the problem in terms of the changes in model and data—not in terms of model and data. This (1) focuses the inversion on the model change, making it easy to apply restrictions and limitations on the model change during seismic inversion; the ROB-inversion essentially restricts the model change to be in terms of the (process-derived) Reduced-Order Basis functions. Furthermore, it (2) allows for the training images to be defined explicitly in terms of the time-lapse changes to the baseline model. The change is generally constrained—by the physics of the flow and the rock properties model, making a representative training image set to be reasonably attainable. An advantage of my approach over existing sparse time-lapse techniques is that it allows for fixed data acquisition configurations over calendar-time. Hence, the cost and turn-around time associated with redeployment of seismic data acquisition equipment can be minimized. In order to demonstrate my approach, I focus on borehole-based monitoring, namely, crosswell data acquisition geometry; nevertheless, it can be adapted to other geometries (surface-based or borehole-based) and other geophysical data (e.g., resistivity, electromagnetic, etc.). It can also be adapted for monitoring other processes, such as assessing the performance of Improved Oil Recovery (IOR). In this thesis, I demonstrate the practicability of my approach on synthetic and field traveltime crosswell datasets. I show, with synthetic and field data, its effectiveness for leak detection during CO2 injection.

Download or read book Time Lapse Approach to Monitoring Oil Gas and CO2 Storage by Seismic Methods written by Junzo Kasahara and published by Gulf Professional Publishing. This book was released on 2016-10-14 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Time Lapse Approach to Monitoring Oil, Gas, and CO2 Storage by Seismic Methods delivers a new technology to geoscientists, well logging experts, and reservoir engineers, giving them a new basis on which to influence decisions on oil and gas reservoir management. Named ACROSS (Accurately Controlled and Routinely Operated Signal System), this new evaluation method is presented to address more complex reservoirs, such as shale and heavy oil. The book also discusses prolonged production methods for enhanced oil recovery. The monitoring of storage zones for carbon capture are also included, all helping the petroleum and reservoir engineer to fully extend the life of a field and locate untapped pockets of additional oil and gas resources. Rounded out with case studies from locations such as Japan, Saudi Arabia, and Canada, this book will help readers, scientists, and engineers alike to better manage the life of their oil and gas resources and reservoirs. Benefits both geoscientists and reservoir engineers to optimize complex reservoirs such as shale and heavy oil Explains a more accurate and cost efficient reservoir monitoring technology called ACROSS (Accurately Controlled and Routinely Operated Signal System) Illustrates real-world application through multiple case studies from around the world

Download or read book Monitoring CO2 Storage at Cranfield Mississippi with Time Lapse Offset VSP Using Integration and Modeling to Reduce Uncertainty written by and published by . This book was released on 2014 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: A time-lapse Offset Vertical Seismic Profile (OVSP) data set was acquired as part of a subsurface monitoring program for geologic sequestration of CO2. The storage site at Cranfield, near Natchez, Mississippi, is part of a detailed area study (DAS) site for geologic carbon sequestration operated by the U.S. Dept. of Energy's Southeast Regional Carbon Sequestration Partnership (SECARB). The DAS site includes three boreholes, an injection well and two monitoring wells. The project team selected the DAS site to examine CO2 sequestration multiphase fluid flow and pressure at the interwell scale in a brine reservoir. The time-lapse (TL) OVSP was part of an integrated monitoring program that included well logs, crosswell seismic, electrical resistance tomography and 4D surface seismic. The goals of the OVSP were to detect the CO2 induced change in seismic response, give information about the spatial distribution of CO2 near the injection well and to help tie the high-resolution borehole monitoring to the 4D surface data. The VSP data were acquired in well CFU 31-F1, which is the ~3200 m deep CO2 injection well at the DAS site. A preinjection survey was recorded in late 2009 with injection beginning in December 2009, and a post injection survey was conducted in Nov 2010 following injection of about 250 kT of CO2. The sensor array for both surveys was a 50-level, 3-component, Sercel MaxiWave system with 15 m (49 ft) spacing between levels. The source for both surveys was an accelerated weight drop, with different source trucks used for the two surveys. Consistent time-lapse processing was applied to both data sets. Time-lapse processing generated difference corridor stacks to investigate CO2 induced reflection amplitude changes from each source point. Corridor stacks were used for amplitude analysis to maximize the signal-to-noise ratio (S/N) for each shot point. Spatial variation in reflectivity (used to 'map' the plume) was similar in magnitude to the corridor stacks but, due to relatively lower S/N, the results were less consistent and more sensitive to processing and therefore are not presented. We examined the overall time-lapse repeatability of the OVSP data using three methods, the NRMS and Predictability (Pred) measures of Kragh and Christie (2002) and the signal-to-distortion ratio (SDR) method of Cantillo (2011). Because time-lapse noise was comparable to the observed change, multiple methods were used to analyze data reliability. The reflections from the top and base reservoir were identified on the corridor stacks by correlation with a synthetic response generated from the well logs. A consistent change in the corridor stack amplitudes from pre- to post-CO2 injection was found for both the top and base reservoir reflections on all ten shot locations analyzed. In addition to the well-log synthetic response, a finite-difference elastic wave propagation model was built based on rock/fluid properties obtained from well logs, with CO2 induced changes guided by time-lapse crosswell seismic tomography (Ajo-Franklin, et al., 2013) acquired at the DAS site. Time-lapse seismic tomography indicated that two reservoir zones were affected by the flood. The modeling established that interpretation of the VSP trough and peak event amplitudes as reflectivity from the top and bottom of reservoir is appropriate even with possible tuning effects. Importantly, this top/base change gives confidence in an interpretation that these changes arise from within the reservoir, not from bounding lithology. The modeled time-lapse change and the observed field data change from 10 shotpoints are in agreement for both magnitude and polarity of amplitude change for top and base of reservoir. Therefore, we conclude the stored CO2 has been successfully detected and, furthermore, the observed seismic reflection change can be applied to Cranfield's ...

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 Monitoring CO2 Storage at Cranfield Mississippi with Time Lapse Offset VSP u2013 Using Integration and Modeling to Reduce Uncertainty written by and published by . This book was released on 2014 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: A time-lapse Offset Vertical Seismic Profile (OVSP) data set was acquired as part of a subsurface monitoring program for geologic sequestration of CO2. The storage site at Cranfield, near Natchez, Mississippi, is part of a detailed area study (DAS) site for geologic carbon sequestration operated by the U.S. Dept. of Energy’s Southeast Regional Carbon Sequestration Partnership (SECARB). The DAS site includes three boreholes, an injection well and two monitoring wells. The project team selected the DAS site to examine CO2 sequestration multiphase fluid flow and pressure at the interwell scale in a brine reservoir. The time-lapse (TL) OVSP was part of an integrated monitoring program that included well logs, crosswell seismic, electrical resistance tomography and 4D surface seismic. The goals of the OVSP were to detect the CO2 induced change in seismic response, give information about the spatial distribution of CO2 near the injection well and to help tie the high-resolution borehole monitoring to the 4D surface data. The VSP data were acquired in well CFU 31-F1, which is the 3̃200 m deep CO2 injection well at the DAS site. A preinjection survey was recorded in late 2009 with injection beginning in December 2009, and a post injection survey was conducted in Nov 2010 following injection of about 250 kT of CO2. The sensor array for both surveys was a 50-level, 3-component, Sercel MaxiWave system with 15 m (49 ft) spacing between levels. The source for both surveys was an accelerated weight drop, with different source trucks used for the two surveys. Consistent time-lapse processing was applied to both data sets. Time-lapse processing generated difference corridor stacks to investigate CO2 induced reflection amplitude changes from each source point. Corridor stacks were used for amplitude analysis to maximize the signal-to-noise ratio (S/N) for each shot point. Spatial variation in reflectivity (used to ‘map’ the plume) was similar in magnitude to the corridor stacks but, due to relatively lower S/N, the results were less consistent and more sensitive to processing and therefore are not presented. We examined the overall time-lapse repeatability of the OVSP data using three methods, the NRMS and Predictability (Pred) measures of Kragh and Christie (2002) and the signal-to-distortion ratio (SDR) method of Cantillo (2011). Because time-lapse noise was comparable to the observed change, multiple methods were used to analyze data reliability. The reflections from the top and base reservoir were identified on the corridor stacks by correlation with a synthetic response generated from the well logs. A consistent change in the corridor stack amplitudes from pre- to post-CO2 injection was found for both the top and base reservoir reflections on all ten shot locations analyzed. In addition to the well-log synthetic response, a finite-difference elastic wave propagation model was built based on rock/fluid properties obtained from well logs, with CO2 induced changes guided by time-lapse crosswell seismic tomography (Ajo-Franklin, and others, 2013) acquired at the DAS site. Time-lapse seismic tomography indicated that two reservoir zones were affected by the flood. The modeling established that interpretation of the VSP trough and peak event amplitudes as reflectivity from the top and bottom of reservoir is appropriate even with possible tuning effects. Importantly, this top/base change gives confidence in an interpretation that these changes arise from within the reservoir, not from bounding lithology. The modeled time-lapse change and the observed field data change from 10 shotpoints are in agreement for both magnitude and polarity of amplitude change for top and base of reservoir. Therefore, we conclude the stored CO2 has been successfully detected and, furthermore, the observed seismic reflection change can be applied to Cranfield’s ...

Download or read book Time Lapse Approach to Monitoring Oil Gas and CO2 Storage by Seismic Methods written by Junzō Kasahara and published by Gulf Professional Publishing, is. This book was released on 2017 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Named ACROSS (Accurately Controlled and Routinely Operated Signal System), this new evaluation method is presented to address more complex reservoirs, such as shale and heavy oil. The book also discusses prolonged production methods for enhanced oil recovery. The monitoring of storage zones for carbon capture are also included, all helping the petroleum and reservoir engineer to fully extend the life of a field and locate untapped pockets of additional oil and gas resources. Rounded out with case studies from locations such as Japan, Saudi Arabia, and Canada, this book will help readers, scientists, and engineers alike to better manage the life of their oil and gas resources and reservoirs."--Provided by publisher

Download or read book Investigation of Time lapse 4D Seismic Tuning and Spectral Responses to CO2 EOR for Enhanced Characterization and Monitoring of a Thin Carbonate Reservoir written by Austin Krehel and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Advancements, applications, and success of time-lapse (4D) seismic monitoring of carbonate reservoirs is limited by these systems' inherent heterogeneity and low compressibility relative to siliciclastic systems. To contribute to the advancement of 4D seismic monitoring in carbonates, an investigation of amplitude envelope across frequency sub-bands was conducted on a high-resolution 4D seismic data set acquired in fine temporal intervals between a baseline and eight monitor surveys to track CO2-EOR from 2003-2005 in the Hall-Gurney Field, Kansas. The shallow (approximately 900 m) Plattsburg 'C Zone' target reservoir is an oomoldic limestone within the Lansing-Kansas City (LKC) supergroup -- deposited as a sequence of high-frequency, stacked cyclothems. The LKC reservoir fluctuates around thin-bed thickness within the well pattern region and is susceptible to amplitude tuning effects, in which CO2 replacement of initial reservoir fluid generates a complex tuning phenomena with reduction and brightening of amplitude at reservoir thickness above and below thin-bed thickness, respectively. A thorough analysis of horizon snapping criteria and parameters was conducted to understand the sensitivity of these autonomous operations and produce a robust horizon tracking workflow to extend the Baseline Survey horizon data to subsequent Monitor Surveys. This 4D seismic horizon tracking workflow expedited the horizon tracking process across monitor surveys, while following a quantitative, repeatable approach in tracking the LKC and maintaining geologic integrity despite low signal-to-noise ratio (SNR) data and misties between surveys. Analysis of amplitude envelope data across frequency sub-bands (30-80 Hz) following spectral decomposition identified geometric features of multiple LKC shoal bodies at the reservoir interval. In corroboration with prior geologic interpretation, shoal boundaries, zones of overlap between stacked shoals, thickness variation, and lateral changes in lithofacies were delineated in the Baseline Survey, which enhanced detail of these features' extent beyond capacity offered from well log data. Lineaments dominated by low-frequency anomalies within regions of adjacent shoals' boundaries suggest thicker zones of potential shoal overlap. Analysis of frequency band-to-band analysis reveals relative thickness variation. Spectral decomposition of the amplitude envelope was analyzed between the Baseline and Monitor Surveys to identify spectral and tuning changes to monitor CO2 migration. Ambiguity of CO2 effects on tuning phenomena was observed in zones of known CO2 fluid replacement. A series of lineaments highlighted by amplitude brightening from the Baseline to Monitor Surveys is observed, which compete with a more spatially extensive effect of subtle amplitude dimming. These lineaments are suggestive of features below tuning thickness, such as stratigraphic structures of shoals, fractures, and/or thin shoal edges, which are highlighted by an increased apparent thickness and onset of tuning from CO2. Detailed analysis of these 4D seismic data across frequency sub-bands provide enhanced interpretation of shoal geometry, position, and overlap; identification of lateral changes in lithofacies suggestive of barriers and conduits; insight into relative thickness variation; and the ability of CO2 tuning ambiguity to highlight zones below tuning thickness and improve reservoir characterization. These results suggest improved efficiency of CO2 -EOR reservoir surveillance in carbonates, with implications to ensure optimal field planning and flood performance for analogous targets.

Download or read book Monitoring of CO2 injected at Sleipner using time lapse seismic data written by R. Arts and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Assessing Uncertainty and Repeatability in Time Lapse VSP Monitoring of CO2 Injection in a Brine Aquifer Frio Formation Texas A Case Study written by and published by . This book was released on 2013 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study was done to assess the repeatability and uncertainty of time-lapse VSP response to CO2 injection in the Frio formation near Houston Texas. A work flow was built to assess the effect of time-lapse injected CO2 into two Frio brine reservoir intervals, the 'C' sand (Frio1) and the 'Blue sand' (Frio2). The time-lapse seismic amplitude variations with sensor depth for both reservoirs Frio1 and Frio2 were computed by subtracting the seismic response of the base survey from each of the two monitor seismic surveys. Source site 1 has been considered as one of the best sites for evaluating the time-lapse response after injection. For site 1, the computed timelapse NRMS levels after processing had been compared to the estimated time-lapse NRMS level before processing for different control reflectors, and for brine aquifers Frio1, and Frio2 to quantify detectability of amplitude difference. As the main interest is to analyze the time-lapse amplitude variations, different scenarios have been considered. Three different survey scenarios were considered: the base survey which was performed before injection, monitor1 performed after the first injection operation, and monitor2 which was after the second injection. The first scenario was base-monitor1, the second was basemonitor2, and the third was monitor1-monitor2. We considered three 'control' reflections above the Frio to assist removal of overburden changes, and concluded that third control reflector (CR3) is the most favorable for the first scenario in terms of NRMS response, and first control reflector (CR1) is the most favorable for the second and third scenarios in terms of NRMS response. The NRMS parameter is shown to be a useful measure to assess the effect of processing on time-lapse data. The overall NRMS for the Frio VSP data set was found to be in the range of 30% to 80% following basic processing. This could be considered as an estimated baseline in assessing the utility of VSP for CO2 monitoring. This study shows that the CO2 injection in brine reservoir Frio1 (the 'C' sand unit) does induce a relative change in amplitude response, and for Frio2 (the 'Blue' sand unit) an amplitude change has been also detected, but in both cases the uncertainty, as measured by NRMS indicates the reservoir changes are, at best, only slightly above the noise level, and often below the noise level of the overall data set.

Download or read book Time lapse Active Source Seismic Characterization of a Leaky CO2 Reservoir written by Stephen Slivicki and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "A carbon capture and sequestration (CCS) approach requires economical methods to monitor reservoir CO2 flow paths through time. I explore the use of an inexpensive surface seismic approach to monitor the time-varying response of a leaky CO2 reservoir. My site is located in east central Utah, where the Little Grand Wash fault provides a natural analogue for a failed sequestration site. This fault and related anticlinal trap provides a conduit to collect and deliver CO2 from shallow reservoir depths to the atmosphere. Elevated soil CO2 flux measurements, outgassing at the Crystal Geyser, and travertine deposits provide the surface expression of CO2 seeps along and near the fault. Borehole and past geophysical data provide a structural and stratigraphic framework for the site. Through historic and new water temperature data, I identify and characterize eruption cycles at the Crystal Geyser. I show that the frequency and duration of eruptions changes through time, and I observe an overall increase in eruption duration. With a new seismic monitoring approach, I show that a surface-based accelerated weight drop source into a stationary geophone spread is repeatable and appropriate for time-lapse seismic studies to monitor reservoir changes. I show repeated surface and body wave measurements with a 30-hour time-lapse dataset. I model seismic velocity changes with changing CO2 saturation within the main Navajo Sandstone reservoir. My models show that during initial saturations, seismically resolvable reservoir changes are possible to monitor. However, I show that a critically saturated reservoir, like that along the Little Grand Wash fault, shows travel time or amplitude changes that are below the resolving capabilities of my surface-based seismic system. While my surface based seismic approach is not appropriate for monitoring CO2 changes at my field site, this same approach could be used to monitor CO2 changes during initial CCS injection where a larger seismic response would be expected."--Boise State University ScholarWorks.

Download or read book Time lapse Seismic Monitoring of CO2 Storage in Saline Aquifers written by Grace Cairns and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 Integration of Prestack Waveform Inversion and Rock Physics Inversion for CO2 Reservoir Characterization written by Josianne L. Pafeng Tschuindjang and published by . This book was released on 2017 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation addresses a seismic reservoir characterization study and time-lapse feasibility of reservoir monitoring of carbon dioxide using seismic data, via rock physics models, global and local nonlinear inversions. It also aims to investigate the value of data integration, the relative impact of elastic and electrical rock physics model parameters on inverted petrophysical properties, and the feasibility of using resistivity data from time-lapse electromagnetic survey to monitor the displacement of carbon dioxide in the subsurface. This study focuses on the identification of target storage and sealing lithologies for a future carbon dioxide (CO2) monitoring project at the Rock Springs Uplift (RSU), Wyoming, USA. Seismic reservoir characterization aims to estimate reservoir rock and fluid properties such as porosity, fluid saturation, lithology, which are important properties for hydrocarbon exploration as well as carbon dioxide sequestration and monitoring projects. These petrophysical properties affect elastic attributes which in turn, affect the seismic response. Estimating reservoir properties therefore constitutes an inverse problem. Geophysical inverse problems are challenging because of the noise in recorded data, the nonlinearity of the inverse problem, the nonuniqueness of the solutions, etc. Depending upon the complexity of the problems, we can either use a local or a global optimization scheme to solve the specific problem. In this dissertation, we use a multilevel parallelization of a global prestack waveform inversion to three-dimensional seismic data with sparse well-information, to estimate subsurface elastic attributes like P-, S-wave velocity and density. This study contributes to the inversion of 3D large seismic data volume in an efficient computational time while providing high-resolution structural images of the subsurface compared to amplitude-variation-with-offset/angle (AVO/AVA) inversion. Following prestack waveform inversion, we use rock physics models to relate elastic attributes to reservoir properties and apply a local nonlinear least squares inversion scheme based on the trust-region algorithm, to invert elastic attributes for petrophysical properties like porosity and volumetric fractions of minerals. We apply this approach on well log data to validate the method, followed by applying it to the volumes of inverted elastic attributes obtained from prestack waveform inversion, to provide reservoir characterization away from the well. Because a carbon dioxide sequestration project is planned at the Rock Springs Uplift, we also investigate the feasibility of a time-lapse reservoir monitoring for the area using seismic data, by simulating the pressure and fluid effects on elastic velocities and synthetic seismograms. In the final part of this dissertation, we investigate the value of data integration by combining elastic and electrical attributes in a joint petrophysical inversion for reservoir rock and fluid properties. We illustrate the methodology using well log data sets from the Barents Sea and the Rock Springs Uplift, and show that the estimation of reservoir properties can be improved by combining multiple geophysical data. Despite the geological information we might have on a study area, there is often uncertainty in the choice of an adequate rock physics model and its input parameters not only at the well location, but also in areas with sparse well control. This study therefore helps understand the impact of such model parameters on inverted petrophysical properties and how it could affect reservoir interpretation. Next, we use a simple sharp interface model in order to provide a preliminary assessment of the extent of the CO2 plume, and thus address potential leakage risks. We also simulate the spatial distribution of CO2 after injection and compute corresponding resistivity datasets at different spatial resolutions, which we invert for water saturation. This synthetic study helps investigate the ability of monitoring the CO2 displacement using geophysical data.

Download or read book Feasibility of Time lapse Gravity Monitoring of Gas Production and CO2 Sequestrartion Northern Carnarvon Basin Australia written by Wendy Young and published by . This book was released on 2012 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: [Truncated abstract] Time-lapse (4D) seismic data, often used to monitor hydrocarbon production and CO2 injection in subsurface reservoirs, cannot readily detect gas saturation changes under certain conditions. Seismic data respond primarily to variations in the compressibility of a rock, but for gas-fluid mixtures greater than ~20%, a change in gas saturation may cause only a minimal change in the compressibility of the reservoir rock. Therefore, it can be difficult to discriminate reservoirs with high and medium gas saturations using the seismic technique. To better monitor changes in reservoir gas saturation, a non-seismic technique may be more favourable. Complementary geophysical techniques, such as gravity and electromagnetic (EM) methods, respond to subsurface variations in density and resistivity respectively, and these physical properties are highly dependent on the saturation values of the rock's pore fluids. Compared to 4D seismic surveys, time-lapse gravity and EM acquisition costs have the potential to be less expensive; however, they also contain less spatial resolution. Gravity data has an additional benefit of being linearly proportional to changes in mass/density, and thus may be easier to interpret than alternate geophysical data types. To detect small mass changes in offshore subsurface reservoirs requires high precision gravity data, which can be achieved by accurate repositioning of the gravimeters on the seafloor. After applying a variety of data corrections, the change in the gravity signal over time can be related to variations in the fluid saturations or pore pressures in the subsurface reservoir. The time-lapse gravity signal may be particularly useful because the amounts of aquifer influx and/or pressure depletion in an offshore reservoir are key uncertainties impacting ultimate gas recovery. The objective of my thesis research is to develop and perform a feasibility analysis for time-lapse gravity monitoring of gas production and CO2 injection in Northern Carnarvon Basin reservoirs. To do this, I have developed a method to quickly assess the sensitivity of time-lapse gravity measurements to reservoir production or injection related changes. I show that gravity monitoring of Carnarvon gas reservoirs appears to be technically feasible and encourages further detailed assessment on a field-by-field basis. For example, in a strong water-drive scenario, a field-wide height change in the gas-water contact greater than 5 m can produce a detectable gravity response greater than 10 U+006fGal for a reservoir at a depth of 2 km, with a porosity of 0.25 and a net-to-gross sand ratio of 0.70. Alternately, for the same reservoir in a depletion-drive scenario, a 6 MPa (~900 psi) decrease in pressure throughout the field can also produce a detectable gravity response. To monitor CO2 sequestration using the time-lapse gravity technique, I find that it is easier to detect a CO2 plume (or potential leaks) in shallower formations (at or less than 1 km below mudline) compared to deeper storage formations at depths greater than 2 km. In order to produce a detectable gravity anomaly, significant amounts of CO2 in excess of 4-8 MT must be injected for reservoirs at 2 km depth, compared to only 1 MT of CO2 injection for formations at 1 km depth. The methods I have developed to assess the feasibility of gravity monitoring are both flexible and practical...

Download or read book Numerical Modeling of Time lapse Seismic Experiments to Monitor Carbon Dioxide Sequestration in a Layered Basalt Reservoir written by Murari Khatiwada and published by . This book was released on 2009 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: