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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)
Identification & Mapping of Water Slumping Fronts by Ultra-Deep Electromagnetic Logging While Drilling Technology in Lower Cretaceous Reservoirs of Adnoc Onshore
Singh, Maniesh (ADNOC osnhore) | Al Arfi, Saif (ADNOC osnhore) | Boyd, Douglas (ADNOC) | Gerges, Nader (ADNOC) | Fares, Wael (Halliburton) | Clegg, Nigel (Halliburton) | Aki, Ahmet (Halliburton) | Diab, Emad (Halliburton) | Pandey, Vikram (ADNOC onshore) | Mansoori, Maisoon M. (ADNOC onshore) | Seddik, Ibrahim A. (ADNOC onshore) | Reddy, Rathnakar (ADNOC onshore)
Abstract ADNOC's limestone reservoirs suffer from the phenomena of injection water traveling preferentially at the top of the reservoir placing injection water above oil held there by capillary forces. Horizontal wells placed below areas of water override, cause the water above to slump unpredictably, increasing water cut and eventually killing the horizontal. Ultra Deep Directional Electromagnetic (EM) Logging While Drilling (LWD) tools provide the measurements to identify and map these water zones, improving reservoir management and design optimal well placement. 1D & 2D EM inversion modeling was conducted on two of ADNOC's largest oil producing reservoirs to evaluate the ability of an Ultra Deep Directional EM LWD Resistivity tool to identify water slumping in the presence of formation bed resistivity contrasts and predict depths of reliable detection (DOD) under various well trajectory scenarios. The inversion was run using depth of inversions up to 150 ft, the maximum expected vertical distance of tool to injection water. Modeling provided an optimized tool configuration (frequency, transmitter-receiver spacing's) to meet objectives. The inversion results further provided guidance for Geosteering, Geomapping and Geostopping decisions. The inversion results in these reservoirs indicated that the Ultra Deep resistivity tool has a DOD of 50-150 ft to pick reservoir tops and water slumping or non-uniform waterfront boundaries. The real-time inversion will optimize landing and drilling long horizontal section to increase net pay for production and even through sub-seismic faults, measuring changes in the reservoir fluid distribution, reduce drilling risk and exceed well production life. This information will aid in updating static model with water flood areas, reservoir tops, faults and structure, designing better infill well spacing and trajectories within bypass oil regions, designing proactive and not reactive smart well completions to delay or reduce water production and ultimately extended plateau and improve ultimate recovery factor. Furthermore, it will aid resistivity mapping of underlying or overlying reservoirs for future development plans. The encouraging results of this study confirmed to move forward with a field trial in these challenging reservoirs for better reservoir and fluid characterization and its management.
- North America > United States (1.00)
- Asia > Middle East > UAE > Abu Dhabi Emirate > Abu Dhabi (0.15)
- Geology > Rock Type > Sedimentary Rock (0.69)
- Geology > Structural Geology (0.66)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > Asia Government > Middle East Government > UAE Government (0.81)
- Africa > South Africa > Western Cape Province > Indian Ocean > Bredasdorp Basin > Block 9 > EM Field (0.99)
- Asia > Middle East > Saudi Arabia > Thamama Group Formation (0.97)
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)
Developing Carbonate Low Resistivity Pay Using Advanced LWD Ultra-Deep Resistivity with Nuclear Magnetic Resonance and High-Resolution Micro-Resistivity Imaging, A Case Study in a Mature Field, Onshore Abu Dhabi
Fares, Wael (Halliburton, Abu Dhabi, U.A.E.) | Dey, Swapan (ADNOC Offshore, Abu Dhabi, U.A.E.) | New, Paul (ADNOC Offshore, Abu Dhabi, U.A.E.) | Albreiki, Warda (ADNOC Offshore, Abu Dhabi, U.A.E.) | Bin Abd Rashid, Atiqurrahman (ADNOC Offshore, Abu Dhabi, U.A.E.) | Lopez, Gabriela (Halliburton, Abu Dhabi, U.A.E.) | Ghobashy, Ahmed (Halliburton, Abu Dhabi, U.A.E.) | Mubeen, Muhammad (Halliburton, Abu Dhabi, U.A.E.) | Clegg, Nigel (Halliburton, Abu Dhabi, U.A.E.)
Abstract One of the major challenges in low resistivity pay zones (below 1 ohm.m) is to map the surrounding boundaries and the reservoir thickness. This has a significant impact on the understanding of the subsequent hydrocarbon production. This case study presents an effective approach in two recent wells where effective well placement and formation evaluation were achieved using Multiple Logging While Drilling (LWD) sensors, including Ultra-Deep Azimuthal Resistivity (UDAR) mapping technology in low resistivity carbonate zone. Extensive pre-well modeling analysis performed for both wells using all available nearby offset wells has concluded that the UDAR technology would be sensitive enough to identify the low resistivity zones in two 6-in. laterals in two wells. In Well 1, 4 ¾-in. Gamma Ray, Wave Propagation Resistivity, Density/Neutron and UDAR Logging-While-Drilling (LWD) sensors were used to drill approximately 3,200 feet. Well 2 was planned as a 6-in. lateral with Maximum Reservoir Contact (MRC) up to 8,466 feet, intersecting two carbonate layers. The Bottom Hole Assembly (BHA) included an even larger suite of LWD sensors, comprising UDAR, Gamma Ray, Wave Propagation Resistivity, Laterolog Micro-Resistivity Imager, Density/Neutron and Nuclear Magnetic Resonance (NMR). 1-Dimensional (1D) and 3-Dimensional (3D) inversions of the UDAR data in real-time allowed a precise mapping of formations and fluid boundaries at great distance from the wellbore. Wells 1 and 2 were drilled successfully through their respective defined target zones. In Well 1, the UDAR 1D inversion identified and confirmed the low resistivity zone below the trajectory and helped to keep the well in target zone till well TD. In Well 2, the UDAR real-time 1D and 3D inversions assisted in precisely mapping complex carbonate reservoir boundaries. Furthermore, the integration of the UDAR 1D and 3D mapping with the NMR measurements allowed identifying the bound water intervals and the direction. In addition, Laterolog Micro-Resistivity Imaging confirmed the presence of vugs and fractures along the wellbore. While moving up to the second target layer, the UDAR 1D inversion successfully mapped the reservoir boundaries, despite the low resistivity of the reservoir (0.7 – 1 Ohm.m). The array of resistivity sensors provided real-time information on the oil saturation, which helped in maximizing reservoir contact by placing the well strategically. Furthermore, the improved reservoir understanding, and insight provided by the integration of UDAR for boundary mapping, NMR for permeability and porosity readings, and Micro-Resistivity Imaging for aperture identifications assisted in optimizing the completion design to isolate unproductive intervals along the well path and delay possible water influx. Successful placement of these laterals in the productive zones despite the low resistivity normally limiting formation and boundary detection brought increased reservoir understanding and optimization of the completion design, confirming the LWD solution adequacy for such environment.
- Geophysics > Seismic Surveying > Borehole Seismic Surveying (1.00)
- Geophysics > Borehole Geophysics (1.00)