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Collaborating Authors
University of Calgary
Time-lapse FWI prediction of CO2 saturation and pore pressure
Hu, Qi (University of Calgary) | Innanen, Kristopher (University of Calgary)
The estimation of CO2 saturation and pore pressure from timelapse seismic data requires a physical model relating the variations in reservoir properties to the changes in seismic attributes. We propose a complete rock physics workflow combing the modified Macbethโs relation and Gassmannโs equation to predict elastic properties as a function of porosity, mineralogy, saturation, and pressure. We validate this workflow using a published dataset. In particular, we demonstrate the advantages of Macbethโs model in predicting the effect of pressure changes. Furthermore, we propose a full waveform inversion (FWI) algorithm incorporating the proposed model for predicting the time-evolution of CO2 saturation and pore pressure. This approach allows for direct updating of reservoir properties from seismic data. We derive static rock properties, such as porosity and clay content, from baseline data and use them as input to predict dynamic reservoir properties (saturation and pressure) from monitor data. We illustrate the potential of the approach using a synthetic time-lapse dataset.
- Geophysics > Time-Lapse Surveying > Time-Lapse Seismic Surveying (0.74)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling (0.71)
- Geophysics > Seismic Surveying > Seismic Interpretation (0.54)
- Geophysics > Seismic Surveying > Seismic Processing (0.47)
- Reservoir Description and Dynamics > Storage Reservoir Engineering > CO2 capture and sequestration (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (1.00)
- (2 more...)
Quantitative FWI characterization of reservoir properties at the CMC Newell County Facility
Hu, Qi (University of Calgary) | Eaid, Matthew (Chevron Technical Center) | Keating, Scott (ETH Zurich) | Innanen, Kristopher (University of Calgary) | Cai, Xiaohui (University of Calgary)
We apply a sequential inversion scheme combining elastic FWI and Bayesian rock physics inversion to a VSP dataset acquired with accelerometers and collocated DAS fiber at the Carbon Management Canadaโs Newell County Facility. The goal is to build a baseline model of porosity and lithology parameters to support later monitoring of CO2 storage. The key strategies include an effective source approach to cope with near-surface complications, a modeling strategy to simulate DAS data directly comparable to the field data, and a Gaussian mixture approach to capture the bimodality of rock properties. We perform FWI tests on the accelerometer, DAS, and combined accelerometer-DAS data. While the results can accurately reproduce either type of data, the elastic models from the accelerator data outperform the other two in matching well logs and identifying the target reservoir. We attribute this result to the insignificant advantage of DAS data, in this case, over accelerometer data, which also suffers from single-component measurements and lower signal-to-noise ratios. The porosity and lithology models predicted from the accelerometer elastic models are reasonably accurate at the well location and are geologically meaningful in spatial distribution.
- Geology > Rock Type (1.00)
- Geology > Geological Subdiscipline > Geomechanics (0.74)
- Reservoir Description and Dynamics > Storage Reservoir Engineering > CO2 capture and sequestration (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Health, Safety, Environment & Sustainability > Environment > Climate change (1.00)
Real-time and quantitative monitoring of CO2 injection with rapid-repeat time-lapse vertical seismic profile data
Cai, Xiaohui (University of Calgary) | Innanen, Kristopher (University of Calgary) | Hu, Qi (University of Calgary) | Keating, Scott (ETH, Zurich) | Eaid, Matthew (Chevron) | Lawton, Donald (Carbon Management Canada)
In recent years our research group has observed quasi-transient changes in seismic transmission data associated with CO2 injection (Innanen et al., 2019). Here, we present images generated through elastic full waveform inversion (EFWI) of rapid-repeat time-lapse vertical seismic profile (VSP) field data, acquired with a fixed source shooting across an injection plume at roughly 15-minute intervals over several days. These images, achieved by the combined distributed acoustic sensing (DAS) and geophone data, represent snapshots of clear transient changes in the vicinity of the injection well. The field data inversion images demonstrate the combined sparse-space geophone and DAS VSP can be new and informative monitoring modes.
- North America > United States (0.47)
- North America > Canada > Alberta (0.29)
- Information Technology > Architecture > Real Time Systems (0.42)
- Information Technology > Communications > Networks (0.35)
Field assessment of elastic full waveform inversion of combined accelerometer and distributed acoustic sensing data in a vertical seismic profile configuration
Eaid, Matthew V. (University of Calgary, Chevron Technical Center) | Keating, Scott D. (University of Calgary) | Innanen, Kristopher A. (University of Calgary) | Macquet, Marie (University of Calgary) | Lawton, Don (University of Calgary)
Seismic data are a significant facilitator for monitoring in carbon capture and sequestration projects, providing high resolution images of fluid migration, using for example full waveform inversion (FWI). Distributed acoustic sensing (DAS), a relatively novel technology for wavefield sampling, is well suited for this type of monitoring. Employing non-invasive optical fibers, DAS allows for dense spatial sampling along the entire length of the well bore, without disrupting operations. Permanently installed in the wellbore, typically behind casing, DAS offers highly repeatable and dense sampling of the transmitted wave modes crucial to seismic monitoring of injected carbon dioxide. However, DAS data consists of measurements of strain along the tangent of the fiber, and therefore does not port directly to conventional FWI algorithms. We describe how DAS data in its native strain (or strain-rate) form can be incorporated into standard FWI algorithms, through changing the definition of a receiver sampling operator that uses geometrical information about the fiber to supply tangential strain measurements to the FWI residual. The theoretical developments are applied to invert field VSP acquired with both DAS fiber and accelerometers at a carbon dioxide sequestration site in Newell Country, Alberta. Our method incorporates DAS data and accelerometer data in one objective function, and allows us to tune the relative importance we wish to place on each dataset. This method should also transfer to non-collocated sensors, for example surface deployed geophones and borehole fiber. The inverted models contain features expected from the geology of the field site, and data modeled in the inverted models compares favorably with field data for both sensor types. The models derive from data acquired prior to CO2 injection, representing baseline models for future timelapse studies planned at the field research station.
- North America > United States (0.67)
- North America > Canada > Alberta (0.48)
- Reservoir Description and Dynamics > Storage Reservoir Engineering > CO2 capture and sequestration (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Near-well and vertical seismic profiles (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
Simultaneous waveform inversion of seismic-while-drilling data for P-wave velocity, density, and source parameters
Li, Jinji (University of Calgary) | Keating, Scott D. (University of Calgary) | Innanen, Kristopher A. (University of Calgary) | Shor, Roman (University of Calgary) | Kazemi, Nasser (Universit du Qubec Montral)
Full-waveform inversion (FWI), as an optimization-based approach to estimating subsurface models, is limited by incomplete acquisition and illumination of the subsurface. The incorporation of additional data from new and independent ray paths should be expected to result in significant increase in the accuracy of FWI models. In principle, seismic-while-drilling (SWD) technology can supply these additional ray paths; however, it introduces a new suite of unknowns, namely precise source locations (i.e., drilling path), source signature, and radiation characteristics. Here we formulate a new FWI algorithm in which source radiation patterns and positions join the velocity and density values of the grid cells as unknowns to be determined. We then conduct several numerical inversion experiments with different source settings, using a synthetic model. The SWD sources are supplemented by explosive sources and multi-component receivers at the surface, simulating a conventional surface acquisition geometry. The subsurface model and SWD source properties are recovered and analyzed. The analysis is suggestive that SWD involvement can enhance the accuracy of FWI models, with varying degrees of enhancement depending on factors such as trajectory inclination, source density, and drill path extension. The impact of SWD-FWI over standard FWI is reduced when low-frequency data are missing, but improvements over the models constructed with no subsurface sources remain. This formulation permits general source information, such as position and moment tensor components, to be independently obtained. This inversion scheme may lead to a range of potential applications#xD;where both medium properties and source information are required.
- North America > Canada (0.67)
- North America > United States (0.46)
- Reservoir Description and Dynamics > Reservoir Simulation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic modeling (1.00)
- Data Science & Engineering Analytics > Information Management and Systems (1.00)
Summary For enhanced geothermal systems (EGS), multistage hydraulic fracturing along a deviated or horizontal well is a key technology used to create a high-conductivity fracture network between injection and production wells in deep, low-permeability geothermal reservoirs. The purpose of the created fracture network is to allow for the efficient transfer of fluid, heated by the geothermal reservoir, from the injection to the production well; therefore, well spacing (between injection and production wells) and hydraulic fracturing must be designed not only to promote connectivity between well pairs but also to mitigate thermal short-circuiting and thermal breakthrough. Analysis of post-fracture pressure decay (PFPD) data measured after each stage of a hydraulic fracturing treatment can be used to provide critical reservoir and fracture parameters required for well and hydraulic fracturing design optimization; this method provides a low-cost alternative and complementary approach to in-situ observation techniques, such as core-through experiments, fiber optics, or image logs in offset wells. Until now, PFPD has primarily been applied to multifractured horizontal wells (MFHWs) completed in low-permeability hydrocarbon reservoirs. The goal of this study is therefore to develop a methodology to estimate fracture and reservoir parameters using stage-by-stage PFPD data associated with EGS projects. An analytical model is proposed herein to estimate fracturing fluid efficiency, fracture length, average fracture aperture, average fracture conductivity, and reservoir permeability for different possible fracture geometries in EGS reservoirs. PFPD data collected for three hydraulic fracture stages in the injection well at the Utah Frontier Observatory for Research in Geothermal Energy (FORGE) site were analyzed to demonstrate the practical application of the proposed method. The results of this study indicate that, due to the presence of natural fractures in the target (granitic) reservoir, the hydraulic fracturing treatment (using slickwater) in the openhole section resulted in low fracturing fluid efficiency and small hydraulic fractures. In contrast, hydraulic fracturing treatments conducted in the perforated casedhole wellbore resulted in higher fracturing fluid efficiency and created larger hydraulic fractures even with smaller injected volumes. The results of the PFPD analysis were confirmed using a Formation MicroScanner image log and microseismic data collected during each stage of hydraulic fracturing.
- North America > United States > Utah (0.62)
- North America > United States > Texas (0.46)
- Geophysics > Seismic Surveying > Passive Seismic Surveying > Microseismic Surveying (1.00)
- Geophysics > Borehole Geophysics (1.00)
- Energy > Renewable > Geothermal > Geothermal Resource (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Energy > Renewable > Geothermal > Geothermal Resource for Power Generation > Enhanced Geothermal System (0.61)
- Oceania > Australia > South Australia > Cooper Basin (0.99)
- Oceania > Australia > Queensland > Cooper Basin (0.99)
- North America > United States > Texas > Permian Basin > Delaware Basin (0.99)
- North America > United States > New Mexico > Permian Basin > Delaware Basin (0.99)
ABSTRACT Geophysical and geologic data, e.g.,ย results obtained using rock cores, outcrops, and borehole images, reveal the presence of multiple sets of fractures in rock. To analyze how fracture interactions affect seismic anisotropy and dispersion, we consider an effective model that contains two sets of orthogonal fractures. In seismic amplitude analysis, we focus on the case of subsurface target zones containing a fracture network composed of primary and secondary fracture sets. Focusing on gas-bearing rocks with small fracture densities, we formulate simplified stiffness parameters in terms of two groups of fracture weaknesses, which are related to the primary and secondary fractures, respectively. Using the simplified stiffness parameters, we derive the PP-wave reflection coefficient and the azimuthal elastic impedance (AEI) as functions of the two groups of normal and tangential fracture weaknesses. Based on the derived PP-wave reflection coefficient and AEI, we propose a method and workflow in which the azimuthal variations of the partial incidence-angle-stacked seismic data are used to estimate the AEI and differences in AEI (which we refer to as DEI) is input to a nonlinear inversion for two groups of fracture weaknesses. In the nonlinear inversion, the initial values of fracture weaknesses are obtained based on a two-term approximation of the PP-wave reflection coefficient. First- and second-order derivatives of DEI with respect to fracture weakness parameters are calculated to generate the update in the unknown parameter vector. Synthetic seismic gathers with varying signal-to-noise ratios are used to validate the robustness of the estimation. Applying the inversion method to a real data set, we obtain what we interpret to be reliable fracture weakness estimates that produce azimuthal amplitude differences matching those extracted from real seismic data. The results provide a potential tool for determining if two sets of fractures have developed in a reservoir.
- Asia > China (0.28)
- North America > Canada > Alberta (0.28)
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling (0.88)
Wettability Alteration of Reservoir Rock by Nonionic, Anionic and Cationic Surfactant in Water-Based Drilling Fluid
Kiani, Mohammad (Secure Energy) | Mirza, Mohammad Ali (University of Calgary) | Erfanian, Elnaz (University of Calgary) | Jafarifar, Iman (University of Kerman)
Abstract The interaction between clay minerals in formations and drilling fluids was analyzed through a study of four core plugs in different types of fluid, including gas oil, anionic surfactant (SDS), non-ionic surfactant (PEG), and cationic surfactant (CTAB). The core plugs were cut for petrophysical tests, including permeability, saturation, X-ray diffraction, and petrographical analyses. The original samples contained clay minerals such as illite and smectite. A static immersion test revealed that swelling and dispersing changed the original petrophysical rock properties of the samples. The addition of nanoparticles of Ca, K, Na, Cl at low, high, and saturated salinity in sodium chloride (NaCl), potassium chloride (KCl), and calcium chloride (CaCl2) was used to reduce active shale and increase mud density from 8.33 to 11.8 ppg, improving petrophysical rock properties by reducing filtration and swelling. The permeability and water saturation were measured before and after core injection of the drilling fluids. The results showed that surfactants (PEG) > (SDS) > (CTAB) in a water-based drilling fluid improved fluid loss and viscosity and reduced the interfacial tension, shifting the reservoir wettability towards a more water-wet state in low, high, and saturation salinity. The use of surfactants in water-based mud reduced formation damage and increased well productivity.
- Geology > Mineral > Silicate > Phyllosilicate (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.35)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (1.00)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid management & disposal (1.00)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (1.00)
- (4 more...)
Characterizing hydraulic fracture growth using DAS-recorded microseismic reflections
Ma, Yuanyuan (University of Calgary) | Eaton, David W. (University of Calgary) | Wang, Chaoyi (University of Calgary) | Aklilu, Alemayehu (ConocoPhillips Canada)
Hydraulic fracturing is crucial for enhancing hydrocarbon production from unconventional reservoirs. The characterization of fracture geometry and propagation has significant value in understanding reservoir response and designing more efficient completions. Distributed acoustic sensing (DAS) is a rapidly developing technology that can be used for this purpose because it provides wide-aperture observations of microseismic wavefields that contain direct P and S arrivals as well as converted and reflected waves. In addition to traditional approaches for microseismic event location and source mechanism analysis, the high spatial resolution of DAS microseismic recordings allows the imaging of induced fractures with reflected waves. Reflections are generated by waves radiated from microseismic events that impinge on hydraulic fractures created during prior treatment stages. We use a straightforward method based on f-k filtering and ray tracing to map reflected S waves from the time domain to reflectivity in the space domain. A case study of fracture imaging indicates that inferred fracture development, based on reflection imaging, is consistent with fracture-driven interactions observed using low-frequency DAS (LF-DAS) data. In addition, this study reveals reflection images of apparent distal fractures that do not reach the fiber and thus are not directly observed by LF-DAS. Fracture images obtained from several microseismic events during the same stage provide the opportunity to observe snapshots of dynamic fracture evolution processes.
- North America > United States (0.68)
- North America > Canada > Alberta > Census Division No. 6 > Calgary Metropolitan Region > Calgary (0.28)
Effect of CO2 Dissolution on Fluid Flow and Phase Behavior in Oil-Water Systems in Shale Reservoirs
Song, Yilei (China University of Petroleum (Beijing) / University of Calgary) | Song, Zhaojie (China University of Petroleum (Beijing)) | Meng, Yufan (China University of Petroleum (Beijing)) | Ma, Haoming (University of Calgary) | Chen, Zhangxin (China University of Petroleum (Beijing) / University of Calgary) | Zhang, Yunfei (China University of Petroleum (Beijing)) | Zhang, Lichao (China University of Petroleum (Beijing)) | Feng, Dong (China University of Petroleum (Beijing))
Abstract The utilization of CO2 as an injection agent to enhance shale oil recovery has garnered significant attention. Nonetheless, the introduction of CO2 results in complex phase behavior and flow mechanisms of formation fluids. Thus, a comprehensive framework consisting of theoretical models and algorithms has been developed to explore the impact of CO2 dissolution on fluid phase behavior and flow within shale oil-water systems. In this study, an improved multi-phase flash algorithm is introduced that utilizes a fugacity calculation model incorporating adsorption effects to compute the fluid properties of shale oil-water-CO2 mixtures in nanopores. The findings indicate that the system comprises two phases, namely an oil-rich phase and a water-rich phase, independent of the CO2 feed. Additionally, a representative pore network of shale is obtained by employing three-dimensional FIB-SEM imaging, encompassing 6,914 pores and 10,725 throats. Finally, pore network modeling is carried out to simulate steady-state oil-water flow, taking into adsorption, slip effects, and changes in fluid properties caused by nano-confinement and CO2 dissolution. With the increase in the mole fraction of CO2, the molecular weight of the oil phase decreases significantly, while that of the aqueous phase slightly increases. Changes in fluid composition leads to a slight increase in the density of both phases, a decrease in the viscosity of the oil phase and the interfacial tension between the phases. These physical property changes result in a significant increase in the flow rate of the oil phase and a minor decrease in the flow rate of the aqueous phase. The average flow rate of the oil phase increases by 3.26 times when the CO2 mole fraction rises from 1.96% to 51.96%. This study enhances our understanding of the phase equilibrium and flow mechanisms in shale oil reservoirs and offers guidance for the development of enhanced oil recovery methods for shale reservoirs.
- North America (0.68)
- Asia > China > Heilongjiang Province (0.46)
- Asia > China > Heilongjiang > Songliao Basin > Daqing Field > Yian Formation (0.99)
- Asia > China > Heilongjiang > Songliao Basin > Daqing Field > Mingshui Formation (0.99)