Download or read book Monitoring CO2 Injection at the Farnsworth EOR Field in Texas Using Joint Inversion of Time lapse VSP Data written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Time lapse VSP Data Processing for Monitoring CO2 Injection written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As a part of the effort of the Southwest Regional Partnership on Carbon Sequestration supported by U.S. Department of Energy and managed by the National Energy Technology Laboratory, two sets of time-lapse VSPs were acquired and processed in oil fields undergoing CO2 injection. One set of VSPs was acquired at the Aneth oil field in Utah, the other set at the Scurry Area Canyon Reef Operators Committee (SACROC) field in West Texas. One baseline and two repeat VSP surveys were conducted from 2007 to 2009 at the Aneth oil field in Utah for monitoring CO2 injection. The aim of the time-lapse VSP surveys is to study the combined enhanced oil recovery (EOR) and CO2 sequestration in collaboration with Resolute Natural Resources, Inc. VSP data were acquired using a cemented geophone string with 60 levels at depth from 805 m to 1704 m, and CO2 is injected into a horizontal well nearby within the reservoir at depth approximately from 1730 m to 1780 m. For each VSP survey, the data were acquired for one zero-offset source location and seven offset source locations (Figure 1). The baseline VSP survey was conducted before the CO2 injection. More than ten thousand tons of CO2 was injected between each of the two repeat VSP surveys. There are three horizontal injection wells, all originating from the same vertical well. One is drilled towards Southeast, directly towards the monitoring well (Figure 2), and the other two towards Northwest, directly away from the monitoring well. The injection is into the top portion of the Desert Creek formation, just beneath the Gothic shale, which acts as the reservoir seal. The initial baseline acquisition was done in October 2007; subsequent time-lapse acquisitions were conducted in July 2008, and January 2009. The acquisition geometry is shown in Figure 1. Shot point 1 is the zero-offset source location, Shot points 2 to 8 are the seven offset VSPs, arranged in a quarter circle on the Northwest side of the monitoring well. The horizontal injection well is shown in green. The black lines in Figure 1 show the approximate reflection coverage al reservoir depth from the respective offset source locations. VSP source location 5 is in a direct line with the injection. The 60 geophone sondes were cemented into the monitor well just before the baseline VSP acquisition and consisted of 96 geophone channels, with 18 three-component geophones (at the bottom of the string) and 42 single vertical component phones above. For this study, only the vertical geophone data were used.

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.

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 3D VSP Monitoring of a CO2 Injection Project at Delhi Field Louisiana written by Muhammad Husni Mubarak Lubis and published by . This book was released on 2012 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 Crosswell Seismic and VSP Monitoring of Injected CO2 Ina Brine Aquifer written by and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic surveys successfully imaged a small scale C02injection (1,600 tons) conducted in a brine aquifer of the Frio Formationnear Houston, Texas. These time-lapse bore-hole seismic surveys, crosswell and vertical seismic profile (VSP), were acquired to monitorthe C02 distribution using two boreholes (the new injection well and apre-existing well used for monitoring) which are 30 m apart at a depth of1500 m. The crosswell survey provided a high-resolution image of the C02distribution between the wells via tomographic imaging of the P-wavevelocity decrease (up to 500 mls). The simultaneously acquired S-wavetomography showed little change in S-wave velocity, as expected for fluidsubstitution. A rock physics model was used to estimate C02 saturationsof 10-20 percent from the P-wave velocity change. The VSP survey resolveda large ( -70 percent) change in reflection amplitude for the Friohorizon. This C02 induced reflection amplitude change allowed estimationof the C02 extent beyond the monitor well and on 3 azimuths. The VSPresult is compared with numerical modeling of C02 saturations and isseismically modeled using the velocity change estimated in the crosswellsurvey.

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 Reservoir Characterization written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Lawrence Livermore National Laboratory is currently involved in a long term study using time-lapse multiple frequency electromagnetic (EM) imaging at a carbon dioxide (CO2) enhanced oil recovery (EOR) site in the San Joaquin Valley, California. The impetus for this proposed research project is to develop the ability to image subsurface CO2 during EOR processes while simultaneously discriminating between background heavy petroleum and water deposits. Using field equipment developed at Lawrence Livermore National Laboratory in prior imaging studies of EOR water and steam injection, this research uses multiple field deployments to acquire subsurface image snapshots of the CO2 injection and displacement. Laboratory research, including electrical and transport properties of fluid and CO2 in saturated materials, uses core samples from drilling, as well as samples of injection and formation fluid provided by industrial partners on-site. Our two-fold approach to combine laboratory and field methods in imaging a pilot CO2 sequestration EOR site using the cross-borehole EM technique is to (1) improve the inversion process in CO2 studies by coupling field results with petrophysical laboratory measurements and (2) focus on new gas interpretation techniques of the field data using multiple frequencies and low noise data processing techniques. This approach is beneficial, as field and laboratory data can provide information on subsurface CO2 detection, CO2 migration tracking, and the resulting displacement of petroleum and water over time. While the electrical properties of the brine from the prior waterflooding are sharply contrasted from the other components, the electrical signatures of the formation fluid (oil) and CO2 are quite similar. We attempt to quantify that difference under multiple conditions and as a function of injection time. We find that the electrical conductivity signature difference increases over time and we should thus expect to discriminate CO2 as a function of time based on the time scales calculated from linear extrapolation of laboratory 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 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 Preliminary Studies and Baseline Results for the Development of Doremi for CO2 Injection Monitoring at Citronelle Alabama written by Wenya Qi and published by . This book was released on 2010 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis reports the preliminary studies and baseline results for the development of DoReMi (Derivative of Refraction Microtremor) geophysical testing method for CO[subscript]2 injection monitoring at the Citronelle Oil Field in Mobile, Alabama. The overall project explores possible CO[subscript]2-Enhanced Oil Recovery (EOR) in the tertiary production of the Citronelle oil reservoir, as well as the subsequent CO[subscript]2 sequestration in the reservoir and the adjacent saline formations. The objective of the geophysical testing is to establish site characteristics in the oil field for both before and after CO[subscript]2 injections. To avoid disturbing the neighborhood near the oil field, only passive sensing with minimal instrumentation - modified surface ReMi (Refraction Microtremor) method with ambient ground excitation, is conducted.To gain sensing depth of the oil reservoirs with depth of more than 11,000 ft, a wireless accelerometer is used to collect seismic signals at 48 well sites, covering two linear testing lines each with a span of more than 25,000 ft. A sensing depth of 12,500 ft has been achieved. Three visits have been made to the field to collect the testing data before CO[subscript]2 injection for site characterization. 1-D and 2-D shear-wave velocity profiles have been constructed from the analyzed testing data. Profiles establish the baseline data for future measurements and comparisons following CO[subscript]2 injection. A time lapse seismic analysis will be performed with the integration of oil production data to investigate the influence of C0[subscript]2, injection. The shear-wave velocity profiles constructed from the three field tests prior to CO[subscript]2 injection were used in the geostability analysis to determine the possible geohazards that may occur because of the CO[subscript]2 injection into the Rodessa formation. Both overall elastic compressibility of the rock formation (compaction) and localized instability (strain rate) in the reservoir due to the redistribution of stresses from the large changes in reservoir pore-pressure are considered. The results indicated that very small linear deformation will be experienced ([less than] 1.2 ft) by the two oil-producing layers. The strain rate calculated using the effective stress model (0.14%) is below critical which indicates no concerns about localized fracture or collapse.

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 Analysis of Near surface and Atmospheric Monitoring Results from the CO2 enhanced Oil Recovery and Storage Project at Farnsworth Unit Texas written by Leticia de Castro Coutinho and published by . This book was released on 2017 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 this quarter we have continued our development of the inversion procedure for Phase III, in which time-lapse changes in seismic attributes are inverted to yield changes in CO2 fluid properties over time. In order to extract seismic attributes from the Sleipner North Sea CO2 time-lapse data set, a new, detailed interpretation was performed and multiple horizons were picked for the 1994 and 2002 vintages. Traveltime difference maps were constructed at several levels within the Sleipner CO2 injection zone, and were quantitatively analyzed. No traveltime change was seen in the overburden, as expected, while significant changes were seen in the upper half of the CO2 injection zone. Evidence of thin-bed tuning and undershooting was also found. A new semi-automated, quantitative method for estimating time sag anomalies was developed, and was used to calculate the amount of time sag along a selected horizon. The resulting time sag estimates matched those seen in the traveltime difference maps. Such a method will be useful for obtaining rapid, accurate quantitative measurements of traveltime changes in the Sleipner data cubes. The traveltime changes will be combined with other attributes, such as amplitude and frequency changes, for input into the real-data inversion.

Download or read book Electromagnetic Imaging of CO2 Sequestration at an Enhanced Oil Recovery Site written by and published by . This book was released on 2004 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: The two year LDRD-ER-089 project Electromagnetic Imaging of CO2 Sequestration at an Enhanced-Oil-Recovery Site used a dual track approach to imaging and interpreting the effectiveness and migration of CO2 injection at an enhanced oil recovery site. Both field data and laboratory data were used together to aid in the interpretation and understanding of CO2 flow in a heavily fracture enhanced oil recovery site. In particular, project highlights include; {lg_bullet} The development of a low-noise digital field system to measure the EM induction response to CO2 in a variety of field conditions. Central to this system is a low-noise induction receiver antenna that can measure the low-energy response of the CO2. This system has consistently measured a shallow pseudo-miscible CO2 flood at source frequencies between 2.0 kHz and 10 kHz. In addition, the existing and added oil and brine in the formation have also been characterized. {lg_bullet} Comparisons of cross-well images with induction logs acquired before drilling suggest the EM induction resolution for CO2 imaging is equivalent with applications to waterflood imaging completed at LLNL. {lg_bullet} The development and use of laboratory equipment to conduct fluid and gas time-lapsed injection studies of core samples using fluids acquired in the field. Measurements of the resistivity during this injection process and the ability to make instantaneous measurements of the frequency response provide a unique dataset for interpretation. {lg_bullet} The development of an optimum finite difference grid spacing that allows for stable inversions at different frequencies. {lg_bullet} The use of time-lapse field images to show the change of electrical conductivity in the field scales to the laboratory results. Using this result, we can approximate an interpretation of field images based on the rate-of-change of the laboratory results. {lg_bullet} The application of Q-domain processing is not applicable at this site due to high ground conductivity. Q-domain processing requires three decades of frequency to properly spline a waveform. However, this site is limited to two decades of frequency because the high ground conductivity precludes the highest frequency measurement. {lg_bullet} Using these results, we are currently prepared to study other CO2 sites at greater depths where the CO2 and existing petroleum components are miscible. {lg_bullet} Journal paper being prepared for submission to Geophysical Journal International.