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Collaborating Authors
3D Electromagnetic Modeling and Quality Control of Ultradeep Borehole Azimuthal Resistivity Measurements
Davydycheva, Sofia (3DEM Modeling & Inversion JIP) | Torres-Verdín, Carlos (University of Texas at Austin) | Hou, Junsheng (University of Texas at Austin) | Saputra, Wardana (University of Texas at Austin) | Rabinovich, Michael (BP) | Antonsen, Frank (Equinor) | Danielsen, Berit Ensted (Equinor) | Druskin, Vladimir (3DEM Modeling & Inversion JIP and Worcester Polytechnic Institute) | Zimmerling, Jörn (3DEM Modeling & Inversion JIP and University of Uppsala)
ABSTRACT Reliable interpretation of borehole electromagnetic (EM) measurements acquired in horizontal and high-angle wells requires fast, robust, and versatile solutions of forward and inverse problems of Maxwell's system in spatially complex 3D anisotropic formations. Based on recent advances in numerical simulation methods, we implement new 3D anisotropic EM modeling and inversion software and algorithms to simulate ultra-deep azimuthal resistivity (UDAR) measurements and to perform their quality control (QC). The combination of fast modeling and inversion under complex and anisotropic 3D earth-model conditions enables us to accurately quantify the limits of resolution and uncertainty of UDAR measurements. Our software and algorithms allow fast and robust modeling based on the finite-volume homogenization technique together with a special reduced-order gridding procedure. This modeling strategy enables the use of model-independent finite-volume grids in tool coordinates combined with a global-model grid accepting inputs from commonly used 3D earth-model rendering formats. While the tool moves along the well trajectory, the formation determined on the 3D global grid shifts and rotates in tool coordinates. Furthermore, we implement several fast direct and iterative solvers in the modeling/inversion workflow, all of which yield practically identical results. Parallel computing also allows real-time modeling. Our modeling approach is effective for the multi-dimensional inversion of UDAR profiling/logging measurements acquired along arbitrary well trajectories. Benchmarks and examples of UDAR simulations on operator's 3D subsurface models confirm the efficacy of our simulation method. We describe benchmark examples including 3D simulation of commercial UDAR measurements acquired across a spatially complex formation model with two faults. Numerical simulation times for 3,000 couplings of logging points and tool configurations are less than 8 CPU hours on a typical laptop and less than 20 seconds on a supercomputer. The benchmark was also verified against an independent 3D EM modeling method. Our 3D fully anisotropic modeling software can be used for real-time inversion and QC of commercial UDAR tool measurements. A 3D simulation based on a 2D model of the well curtain section (obtained as stitched-together 1D models, i.e., results obtained from 1D inversion of commercial measurements) and comparison of this simulation to actual tool measurements identifies the sections of the well trajectory where 2D-3D inversion is needed to decrease the data misfit to acceptable values (i.e., measurement noise levels). Future endeavors include fast fully anisotropic 2D-3D measurement simulation using adaptive upscaling of 3D models and novel 2D-3D inversion algorithms specifically designed for UDAR measurement conditions. Our goal is to develop real-time 2D and 3D inversion of UDAR measurements for well geosteering and refined 3D subsurface model rendering as additional measurements and geometrical constraints are included into the inversion by asset teams.
- Europe (1.00)
- North America > United States > Texas (0.70)
- Asia (0.68)
- Geophysics > Electromagnetic Surveying > Electromagnetic Modeling (1.00)
- Geophysics > Borehole Geophysics (1.00)
Abstract Integrating the inversions of simultaneously acquired deep and ultra-deep logging while drilling (LWD) azimuthal resistivity measurements can improve the resolution of the overlapping volume under investigation and reduce uncertainty in the far field volume model reconstruction. Both are key tools for precise placement of horizontal wells, the recent enhancements in the downhole tools include surface processing algorithms and advanced visualization techniques that allow higher confidence in well placement decisions through improved understanding of subsurface geology and orientation of sand channels in real-time. The high-definition multi-layer inversion capability of a new generation deep resistivity tool has been utilized along with the 1D and 3D ultra-deep resistivity inversion for a separate established tool, providing detailed visualization of formations both near wellbore and in the far field. Both technologies were compared in reservoirs with varying resistivity profiles and thicknesses. In addition, the resistivity anisotropy analysis from ultra-deep 3D inversion was utilized to confirm lithology around the wellbore differentiating anisotropic shale zones from other lithologies of similar low resistivity. Ultra-deep 3D inversions were processed with fine scale cell sizes and then used to validate the high-resolution deep resistivity inversion results. The integration of multiple inversions with varying capabilities enabled resolving thin reservoir layers in a low-resistivity, low-contrast environment, providing superior resolution within the overlapping volumes of investigation of the deep and ultra-deep resistivities. Customization of the ultra-deep 3D inversion successfully enabled geo-mapping of 1-2 ft thick layers and was used to validate the high-resolution deep resistivity 1D inversion. The increasingly challenging geo-steering decision-making process in a complex drilling environment was addressed by employing the advancement in LWD technologies providing higher signal to noise ratios, multiple frequencies and transmitter-receiver spacings augmented with customized inversions providing superior results. This paper demonstrates the added value, to identify, map and navigate thin reservoir zones. A novel workflow has been developed to improve resolution in deep and ultra-deep resistivity mapping, enabling the identification of thin laminations around the wellbore capitalizing on the latest advancements in LWD geo-steering technologies.
- Asia (1.00)
- North America > United States > Texas (0.28)
Abstract Integrating the inversions of simultaneously acquired deep and ultra-deep logging while drilling (LWD) azimuthal resistivity measurements can improve the resolution of the overlapping volume under investigation and reduce uncertainty in the far field volume model reconstruction. Both are key tools for precise placement of horizontal wells, the recent enhancements in the downhole tools include surface processing algorithms and advanced visualization techniques that allow higher confidence in well placement decisions through improved understanding of subsurface geology and orientation of sand channels in real-time. The high-definition multi-layer inversion capability of a new generation deep resistivity tool has been utilized along with the 1D and 3D ultra-deep resistivity inversion for a separate established tool, providing detailed visualization of formations both near wellbore and in the far field. Both technologies were compared in reservoirs with varying resistivity profiles and thicknesses. In addition, the resistivity anisotropy analysis from ultra-deep 3D inversion was utilized to confirm lithology around the wellbore differentiating anisotropic shale zones from other lithologies of similar low resistivity. Ultra-deep 3D inversions were processed with fine scale cell sizes and then used to validate the high-resolution deep resistivity inversion results. The integration of multiple inversions with varying capabilities enabled resolving thin reservoir layers in a low-resistivity, low-contrast environment, providing superior resolution within the overlapping volumes of investigation of the deep and ultra-deep resistivities. Customization of the ultra-deep 3D inversion successfully enabled geo-mapping of 1-2 ft thick layers and was used to validate the high-resolution deep resistivity 1D inversion. The increasingly challenging geo-steering decision-making process in a complex drilling environment was addressed by employing the advancement in LWD technologies providing higher signal to noise ratios, multiple frequencies and transmitter-receiver spacings augmented with customized inversions providing superior results. This paper demonstrates the added value, to identify, map and navigate thin reservoir zones. A novel workflow has been developed to improve resolution in deep and ultra-deep resistivity mapping, enabling the identification of thin laminations around the wellbore capitalizing on the latest advancements in LWD geo-steering technologies.
- Asia (1.00)
- North America > United States > Texas (0.28)
Improving Well Placement & Reservoir Mapping Using Multi-Interval Inversion of Deep and Extra-Deep LWD Resistivity Measurements
Antonov, Yuriy (Baker Hughes) | Andornaya, Darya (Baker Hughes) | Ghysels, Kjeld (Baker Hughes) | Konobriy, Elena (Baker Hughes) | Martakov, Sergey (Baker Hughes) | Jensen, Kåre Røsvik (Equinor)
ABSTRACT Deep and Extra Deep Logging-While-Drilling (LWD) resistivity measurements are commonly used in the well construction phase to land and navigate within complex geology. The measurements complexity often prohibits their visual interpretation for steering decisions. Such decisions are made after data inversion and based on the 2D or 3D visualizations of resulting inversion models. While the main objective of inversion is to achieve a good match between measured and simulated data, the inversion result is a resistivity model that is used for geological interpretation. To deliver a high confidence in the model interpretation, many important considerations impacting the inversion result have to be addressed such as accuracy, confidence, geological sense, etc. In this paper we present a goal-oriented approach where 1D inversion with lateral regularization is run on several data intervals simultaneously. The algorithm can balance both data match and model continuity delivering geologically meaningful models. The inversion algorithm is generic enough to accommodate any set of measurements with arbitrary weight settings enabling goal-oriented (multi-resolution) inversion. Having deep and extra-deep measurements available in the same well, it is reasonable to run multi-interval inversion on the former for near wellbore analysis, or the latter for large scale reservoir mapping. The developed algorithm delivers more geologically robust resistivity models with improved lateral continuity of layers’ resistivity, thickness, and boundary positions. The level of additional lateral regularization between models can be controlled by the user based on available knowledge about geological environment, or pre-configured for an automated execution. Further quality control (QC) of data match and tool sensitivity ranges helps to understand the validity of features mapped in the inversion results. In summary, the paper focuses on the analysis of the quality of the inversion result and the reliability of interpretation covering some aspects of • Lateral continuity vs data misfit • Parametric models vs picture • Confidence in geological interpretation vs depth of detection • Real-time vs pre- and post-well processing • Tuning for a particular application vs general black-box approach We developed a new data inversion algorithm for the deep and extra-deep resistivity tools. The approach delivers laterally consistent resistivity models without compromising data match. In cases of sharp structural changes such as faults, it also may be used as an indicator for intervals better suitable for 2D/3D processing. At the same time, the resulting model preserves quantitative parameters (boundaries, resistivity/anisotropy values, dip) for interpretation and allows estimation of confidence for those parameters. Robustness of the method is demonstrated on synthetic benchmark and field data from the North Sea.
- Europe > Norway > North Sea > Central North Sea (1.00)
- North America > United States (0.96)
- Asia > Middle East (0.93)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Seismic Processing (0.61)
- Europe > Norway > North Sea > Central North Sea > Utsira High > PL 501 > Block 16/5 > Johan Sverdrup Field > Zechstein Formation (0.99)
- Europe > Norway > North Sea > Central North Sea > Utsira High > PL 501 > Block 16/5 > Johan Sverdrup Field > Viking Formation (0.99)
- Europe > Norway > North Sea > Central North Sea > Utsira High > PL 501 > Block 16/5 > Johan Sverdrup Field > Vestland Group (0.99)
- (30 more...)
- Well Drilling > Drilling Measurement, Data Acquisition and Automation > Logging while drilling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
Past, Present, and Future Applications of Ultradeep Directional Resistivity Measurements: A Case History From the Norwegian Continental Shelf
Sinha, Supriya (Halliburton) | Walmsley, Arthur (Halliburton) | Clegg, Nigel (Halliburton) | Vicuña, Brígido (Halliburton) | Wu, Hsu-Hsiang (Mark) (Halliburton) | McGill, Andrew (Equinor ASA) | dos Reis, Téo Paiva (Equinor ASA) | Nygård, Marianne Therese (Equinor ASA) | Ulfsnes, Gunn Åshild (Equinor ASA ) | Constable, Monica Vik (Equinor ASA) | Antonsen, Frank (Equinor ASA) | Danielsen, Berit Ensted (Equinor ASA)
With the introduction of ultradeep azimuthal resistivity (UDAR) logging-while-drilling (LWD) tools toward the beginning of the last decade, the oil and gas industry went from real-time mapping of formation boundaries a few meters from the wellbore to tens of meters away. This innovation allowed early identification of resistivity boundaries and promoted proactive geosteering, allowing for optimization of the wellbore position. Additionally, boundaries and secondary targets that may never be intersected are mapped, allowing for improved well planning for sidetracks, multilaterals, and future wells. Modern tool design and inversion algorithms allow mapping the reservoir in 3D and exploring the sensitivity of these tools to the electromagnetic field ahead of the measure point for look-ahead resistivity. Improvements in the technology over the past decade have changed the way wellbores are planned, drilled, and completed, and reservoir models are updated. This paper presents a case study summarizing the advances in UDAR measurements and inversions over the last decade. The case study presents the whole workflow from prejob planning, service design, and execution of one-dimensional (1D) and three-dimensional (3D) inversion in addition to the future potential of look ahead in horizontal wells. Prewell simulations provide a guide to expected real-time tool responses in highly heterogeneous formations. This identifies how far from the wellbore 1D inversions can map major boundaries above and below the well. A fault was expected toward the toe of the well, and UDAR was used as a safeguard to avoid exiting the reservoir. Standard 1D inversion approaches are too simplistic in this complex geologic setting. Thus, 3D inversion around the wellbore and ahead of the transmitter is also explored to demonstrate the improvements this understanding can bring regarding geostopping toward the fault and reservoir understanding in general. Successful geosteering requires personnel trained to handle complex scenarios. Geosteering training simulators (GTS) could be efficient tools for training to interpret inversions where the “truth” is known from realistic 3D model scenarios. The team can learn how to best exploit UDAR technology and inversion results within its limits and not extend the interpretation beyond acceptable uncertainty levels. It will also be addressed how the understanding of inversion uncertainty could be updated in real time in the future. The continued future success of UDAR technology and 1D to 3D inversion results for look-ahead and look-around applications will depend heavily on uncertainty management of the inversions to avoid wrong decisions and potentially reduced well economy.
- Africa (0.68)
- North America > United States > Texas (0.46)
- Europe > Norway > North Sea > Northern North Sea (0.28)
- Asia > Middle East > Saudi Arabia > Eastern Province (0.27)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (1.00)
- Geology > Geological Subdiscipline > Stratigraphy (1.00)
- Geology > Sedimentary Geology > Depositional Environment (0.67)
- Geology > Structural Geology > Fault (0.67)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Surface Seismic Acquisition (0.67)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean > Campos Basin > Block BM-C-7 > Peregrino Heavy Field (0.99)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean > Campos Basin > Block BM-C-47 > Peregrino Heavy Field (0.99)
- Europe > Norway > North Sea > Northern North Sea > Statfjord Formation (0.99)
- (25 more...)
- Information Technology > Data Science (1.00)
- Information Technology > Artificial Intelligence (1.00)
- Information Technology > Architecture > Real Time Systems (1.00)