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EAGE/SEG Research Workshop 2017
- Conference date: 28 Aug 2017 - 31 Aug 2017
- Location: Trondheim, Norway
- ISBN: 978-94-6282-222-1
- Published: 28 August 2017
21 - 36 of 36 results
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Results from the First Monitor VSP Survey at the Quest CCS Operation
Authors V. Oropeza Baacci, A. Halladay, S. O'Brien, M. Anderson and N. HendersonThe Quest Carbon Capture and Storage (CCS) Operation is a fully integrated CCS project, designed to safely capture, transport and store more than a million tonnes of CO2 annually. Time-lapse seismic is a key technology deployed by the Quest MMV Plan to ensure both the current and long term security of CO2 storage in the injection zone, the BCS saline aquifer. In the first few years of operation, VSPs are a practical and economical alternative to 3D surface seismic, and as of 2016 a baseline and one monitor 2D DAS VSP survey have been acquired. A summary of the first monitor VSP is presented in this paper, along with a discussion of the acquisition geometry, processing and imaging results. The first monitor VSP was able to conclusively demonstrate the presence of CO2 in the injection zone. An interpretation of the time-lapse results is compared to the dynamic reservoir modelling prediction for the extent of CO2 in the injection zone.
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Optimizing Monitoring Strategies for Contrasting Offshore CO2 Storage Sites
Authors A.K. Furre, S. Bussat, P.S. Ringrose and R. ThorsenA feasibility study for a full scale CCS demonstration project in Norway was conducted in spring 2016, aimed at identifying at least one technically feasible CCS chain (capture, transport and storage). The storage part of the feasibility study investigated three potential storage locations in the North Sea. The main deliverable was a suitability recommendation of the localities, based on technical (capacity and containment) evaluations and an economic assessment. Recommendations for monitoring each potential site were also given in the feasibility study, based on the specific storage reservoir and infrastructure at each site. We discuss optimised sub-surface and environmental monitoring based on regulatory storage requirements, proposing a monitoring plan mainly focussed on seismic and environmental surveys acquired at pre-defined times, such as a baseline prior to CO2 injection, a certain number of surveys acquired during injection, and at least one post-injection survey. These could be towed seismic streamers or a permanent installation, or an optimized combination of the two. In addition, we envisage trigger surveys to be conducted in the case where an anomaly is detected. Continuous downhole pressure gauges in the injection well would provide the primary operational monitoring method, along with conventional surface facility pressure flow rates and compositions.
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Repeatability of P-Cable 3D Seismic Data
Authors M.W. Waage, S.B. Bünz, A.P.F. Plaza-Faverola and K.A.W. WaghornFor the first time, we test the repeatability of high-resolution P-Cable seismic data at three sites with different geological and environmental settings to evaluate its potential as a time-lapse tool. Results are positive and indicate ideal setting for using P-Cable as a time-lapse tool is typical marine sedimentary deposition where the data can be processed to obtain quantitative repeatability measures similar to conventional 3D seismic (NRMS < 0.4; Predictability > 0.9). Repeatability is slightly worse in areas of harder or more chaotic sediments and where the seismic attenuation is large or surface topography steep or rough (NRMS > 0.6 and Predictability > 0.8). 4D anomalies at the active seepage site the Vestnesa ridge are commonly restricted to areas where fluid flow is likely to occur, i.e. that is the chimneys or along the BSR (Bottom Simulating Reflector). The overall results gives us increased confidence that we will be able to interpret real (geological/physical) changes from time-lapse P-Cable seismic data if the right pre-conditions and geological restrictions are faced.
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Applications and Possibilities in Real-time Overburden Surveillance Using Permanent Seismic Sensors
By S. BussatThere is an undeniable need in monitoring of oil and gas operating fields for HSE purposes and optimization of recovery. Currently, only seismic methods provide high resolution images to properly locate subsurface changes. Passive seismic data acquired with permanent seismic receivers could enable us to monitor the subsurface and detect changes in real-time. Hence, by maturing methods to analyse and use passive seismic data in real-time, we aim to improve our understanding of the subsurface, detect problems early, and therefore support mitigating measures to reduce the possible imposed risk. PRM systems can provide real-time seismic data A workflow is presented to continuously analysis passive seismic data for an overburden surveillance, ensuring that only analysed data get deleted. This approach should allow handling more PRM data in the future. The initial experiences gained from the small caprock monitoring system at Oseberg (Bussat et al. 2016), are being transferred to a full-field PRM system with thousands of nodes. New mini-PRM installations for different purposes at various fields are being evaluated and one possible sparse receiver-layout is presented to mitigate problems with strong (platform) noise in the vicinity. Ongoing efforts will investigate the full potential of passive seismic methods in the near future.
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CO2 Monitoring by Using VSP-FWI - Synthetic Study on CO2-saturation and Pressure-buildup Differentiation
Authors T. Tsuchiya, N. Yamada, U.P. Iskandar, M. Kurihara, C. Barnes and M. ChararaSynthetic study on CO2-saturation and pressure-buildup differentiation by using VSP-FWI is conducted in a virtual CCS site. Geophysical and Reservoir simulation works are first implemented to create geophysical models before and after CO2 injection. Virtual VSP-FWI monitoring experiment is then implemented on the models. In parallel with this, simple linear equations to estimate CO2-saturation and pressure-buildup are derived. Inverted P- and S-wave velocities through the VSP-FWI are found to be highly accurate, and used in the derived equation. As a result the saturation change and reduction of differential pressure are estimated consistently with the values after reservoir simulation. This result indicates that CO2-saturation and pressure-buildup can be differentiated around the well, if both P- and S-wave velocities are accurately inferred by applying VSP-FWI and relevant rock-physics model is known.
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Carbon Dioxide Saturation Estimates at Sleipner Using Seismic Imaging and Rock Physics Inversion
Authors B. Dupuy, A. Romdhane, P. Eliasson, H. Yan, V. Torres, E. Querendez and A. GhaderiWe present an integrated approach combining Full-Waveform Inversion and rock physics inversion to estimate CO2 saturation at Sleipner. Acoustic FWI provides high-resolution P-wave velocity images where the uncertainty is quantified using posterior covariance matrix analysis. The seismic properties and their associated uncertainties are used as input to the rock physics inversion. At the fairly large distance of the injection point (533m), we derive CO2 saturations lower than 30% and which are following a patchy mixing distribution.
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CO2 Monitoring by Using VSP-FWI - Timelapse Elastic Parameters Estimation
Authors C. Barnes, M. Charara, T. Tsuchiya and N. YamadaGeological carbon sequestration involves large-scale injection of carbon dioxide into underground geologic formations. Changes in reservoir properties resulting from the CO2 injection and migration can be monitored using time-lapse seismic data. Conventional analysis of time-lapse surface and/or borehole seismic data only gives qualitative information about the changes of the acoustic impedance contrasts in the reservoir. In order to differentiate the pore-pressure from CO2 saturation effects, it is necessary to evaluate the changes in the elastic properties of the reservoir. Borehole seismic data contain strong converted shear waves at the level of the reservoir that will allow determining S-velocity changes. Elastic full waveform inversion (FWI) is the appropriate method to estimate elastic parameters. We demonstrate the feasibility of a timelapse multi-Offset VSP inversion for CO2 sequestration monitoring, by inverting synthetic seismic data based on a virtual CO2 injection site study. The timelapse FWI recovers P-wave and S-wave velocity for the baseline model, i.e., the reference model; and, the perturbations of the velocity models associated to 3 year of CO2 injection are also well recovered for a distance of a few hundreds of meters from the well.
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Results of a baseline magnetometric resistivity survey at the Field Research Station, Alberta
Authors B. Giroux, A. Bouchedda, A. Saeedfar and D. LawtonWith the magnetometric resistivity method (MMR), electrical property contrasts in the ground are obtained from the measure of the magnetic field induced by a galvanic source. Due to the fact that the measurements are done with a magnetic sensor, MMR offers many advantages for monitoring: easier deployment in boreholes (no contact needed) and problems related to electrode installation and corrosion are avoided, also the problem of noise in conductive media is reduced because the magnetic field is a function of current density and not conductivity. The Field Research Station (FRS) is an experimental site operated by the Containment and Monitoring Institute of Carbon Management Canada where are controlled CO2 release experiment is planned for the next 5 years. A preliminary numerical study showed that MMR is suitable for monitoring a CO2 plume at the FRS. In this contribution, we present the results of a baseline survey conducted at the FRS. To our knowledge, this experiment is the first field application of MMR for CO2 monitoring. The aim of the survey was to evaluate the noise conditions at the site and determine the optimal data acquisition parameters, in addition to providing baseline data for a monitoring program.
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Initial Results from the Field on the Use of DAS as a Viable Microseismic Monitoring System of CCS Sites
Authors M. Wilks, A. Wuestefeld, P. Thomas, E. Kolltveit and V. OyeIn outdoor field-tests where a single optical fibre cable is used to make DAS recordings of hammer shots, coherent seismic arrivals are observed at up to 32 m from the hammer points with frequencies up to 600 Hz. Recording at higher sampling rates and decimating is preferable to downsampled data. Time domain SNRs of acquired DAS data at a given distance are ~1/2 those of complimentary geophones while in the frequency domain, the highest ratios are produced between 20 and 200 Hz. An automated STA/LTA trigger algorithm is able to define reasonable seismic onsets but is unable to identify the first-arriving energy on all traces. Shorter pulse widths produce lower RMS amplitudes for the noise windows while longer pulse widths produce higher RMS amplitudes for the signal windows. This means that the selection of optimum pulse width with respect to maximising the SNR is not clear. This work presents the initial results of field-tests that will be used to refine the use of the DAS system in further field and borehole experiments. This will ultimately be used to monitor the seismicity at active CCS injection sites in the future.
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Baseline Microseismic Monitoring for CO2 Injection Sites
Authors A.L. Stork, J.-M. Kendall, A.C. Horleston and D.C. LawtonThis submission describes a baseline passive seismic monitoring experiment for the Field Research Station in Alberta. The analysis does not reveal any local seismicity and we estimate a minimum magnitude (M) of detection of -1.4 for a source-station distance of 500m during quiet periods. Injection tests indicate that the detection threshold will rise to M=-0.1 during injection. Using perforation shots in the injection well we find the array is able to locate seismic events at the planned injection point to within 20m.
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A Passive Microseismic Monitoring Network at the Quest CCS Project
Authors V. Oropeza Bacci, S. O'Brien, M. Anderson, K. Dahlby and N. HendersonThe Quest Carbon Capture and Storage (CCS) Project is a fully integrated CCS project designed to reduce total greenhouse gas emissions from the Scotford Upgrader in Canada by up to 35%. As a component of the Quest MMV Plan, the downhole passive microseismic monitoring network at Quest was designed and installed to address and assess risks associated with induced seismicity, such as cap rock integrity and fault reactivation. A downhole microseismic array is deployed in a deep monitoring well at the central injection well pad, along with a pressure and temperature gauge. The array was designed and manufactured to be a semi-permanent, retrievable array to address any long-term maintenance issues. The technical design criteria were evaluated on the sensitivity based on observations from analog injection operations. This paper presents the details of the Quest microseismic array design and installation, and provides a description of the role passive seismic monitoring plays in the Quest MMV Plan.
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Improvement of Resistivity Imaging for an Offshore CO2 Storage by Filtering Out Seabed Pipeline Influence
More LessOn behalf of NGI, under FME SUCCESS, an MSc thesis at the University of Oslo has been conducted to finalize an inversion study of a CSEM dataset acquired in 2008 for the Sleipner CO2 storage project. The aim of the MSc thesis was to establish an inversion strategy that can be applied in order to resolve some of the various challenges related to inverting the dataset. This paper presents some of the work done related to the influence on the CSEM data from a pipeline network at seabed, with the objective of establishing a method to identify and filter out strongly influenced data, in order to improve inversion results.
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Simulation Approach for the Time-lapse Imaging of CO2 Injected Zones Using a Few Seismic Sources and a Geophone Array
By J. KasaharaThe time-lapse study for the CO2 injection or CO2-EOR requires the excellent repeatability of the measurement system. Many factors control the repeatability. The overburden effects from a source to receivers can be reduced by fix source location. To obtain excellent repeatability, we assume single or a few ACROSS (Accurately Controlled and Routinely Operated Signal System) seismic source(s) which have such ultra-stable repeatability for the operation of long duration. Using residual waveforms before and after the injection of vapor or supercritical CO2 to reservoirs, we can image the time lapse of reservoir. We carried out simulations for a reservoir at 2 km depth. We assumed only one seismic source and a geophone array of variable spacings at the ground surface. The result of simulation gave a precise retrieval of image. For the simulated case, 200 m spacing is enough to resolve the target. In addition, we demonstrate the effect of physical property change in the nearsurface layer which causes interference in imaging of the deep target. Truncating surface-wave components in the residual waveforms could reduce the effect. The applications of our method to the real fields might greatly contribute to reduce the installation and time-lapse monitoring costs.
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Microseismic Monitoring Results from CO2 Storage Operations at Quest
Authors V. Oropeza Bacci, S. O'Brien, M. Anderson, K. Dahlby and N. HendersonThe Quest carbon capture and storage (CCS) project is a fully integrated CCS project developed as part of the Athabasca Oil Sands Project (AOSP), a joint venture between Shell Canada Energy, Chevron Canada Limited, and Marathon Oil Canada Corporation. Although Quest is considered to be in an extremely quiet tectonic location, induced seismicity has been recognized as a potential risk in all large scale injection sites. As a result, microseismic monitoring is a key component of the MMV Plan to ensure the continued assessment of that risk and to provide early notice of any changes. This paper presents the results of passive monitoring at the Quest site through 2016, including the pre-injection baseline period, and the confirmation of the operational sensitivity of the array.
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Integrating Active with Passive Seismic Data to Best Constrain CO2 Injection Monitoring
Authors B.P. Goertz-Allmann, M. Jordan, R. Bauer, V. Oye and S.E. GreenbergThe Illinois Basin - Decatur Project (IBDP) is to date one of the largest CO2 sequestration projects in the United States. So far, 1 Mio tonnes of CO2 have been injected over 3 years into the Mt. Simon sandstone formation at about 2 km depth. A suite of various active and passive seismic monitoring techniques have been applied at the site, providing a rich monitoring dataset. Time-lapse 3D surface seismic and VSP measurements were carried out to delineate the progression of the CO2 front. In addition, passive seismic monitoring revealed over 10’000 microseismic events. As a novel method, we attempt to combine the active and passive seismic data for seismic tomographic inversion for the 4D velocity- and attenuation structure in the reservoir. The combined aperture and higher resolution focuses on the reservoir and may allow a more precise mapping of the injected fluid over time. To investigate 4D changes of velocities and attenuation a similar source and receiver distribution is required. This is a particular challenge for microseismic events. High microseismic event location accuracy is essential, which we intend to improve by near surface material characterization, both from downhole petrophysical logging and seismic velocity logging within newly drilled shallow wells.
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Joint Inversion for Improved CO2 Monitoring at the Ketzin Pilot Site, Germany
Authors M. Jordan, D. Rippe, C. Schmidt-Hattenberger and A. RomdhaneIn this paper we present the joint inversion method, its implementation, and first results of the application using synthetic FWI and ERT data sets for a realistic Ketzin model. This synthetic model was designed to capture the main features of the geology at the Ketzin pilot site and includes a hypothetical CO2 distribution, based on reservoir modelling. Our goal is to improve imaging and quantification of the injected CO2 at the Ketzin pilot site, as well as to improve knowledge about CO2 storage at Ketzin. Using real field data, we aim to mature the joint inversion technology further towards large-scale CO2 storage applications.
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