Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
High angle or horizontal (HA/Hz) wells are commonly drilled to increase reservoir exposure and enhance the overall production. Whereas reservoir navigation highly advance the correct placement of such wells, completion decisions for profit or recovery oriented production optimization require thorough interpretation of available shallow- and deep-reading formation evaluation measurements. Particularly, complex geological environments necessitate the use of reservoir maps and heterogeneity evaluations to understand the likely production behavior. In such applications, formation evaluation measurements from logging-while-drilling (LWD) technology are affected by the relative geometry between well trajectory and the formation. With increasing depth of investigation of the measurements and geological complexity of the reservoirs, these effects become more severe and true properties become uncertain. The multi-propagation-resistivity (MPR) responses show so called polarization horn effects at bed boundaries when beds with a high resistivity contrast are encountered. During the process of inverting these resistivities to obtain true formation resistivity (Rt), inversion algorithms help to reconstruct the complex architecture of downhole formation geometries. This provides a better understanding of the geometrical reservoir complexity and provides insight into the potential future production behavior. Possible corrective actions in production and completion strategies can be derived from such insight. Additional complications like proximity to water transition zone and water coning can be predicted and certain corrective measures, for instance blanking particular zones or placing inflow control devices (ICDs) can be taken, potentially increasing the overall life of the well. This case study presents a horizontal well in a layered Lower Burgan sandstone reservoir of West Kuwait Minagish Field, where a new approach of drilling horizontal sidetracks from abandoned and plugged old vertical wellbores attempted with the purpose of increasing reservoir productivity and tapping into unswept oil. A sidetrack was placed at the roof of the Lower Burgan and navigation while drilling within this complex reservoir was used to stay close to the lithological boundary. Represented by paleo river channel stacked sand bodies, the Lower Burgan formations are overlain by fluvio-tidal sequences of sandstone – siltstone – minor shale alternations of the Upper Burgan with an undulating nature of the lithological boundary. Steering and placing the well in close proximity to this undulating boundary was achieved. The production of this well is exceptionally high with minimum water cut despite a massively increased water transition zone over the last decade. The case demonstrates that an integrated interpretation of the reservoir architecture and heterogeneity along the lateral uncovers the reasoning behind the experienced production. Overall, polarization horns were observed on the propagation resistivity curves. While the interpretation of log artefacts from sole MPR and azimuthal propagation resistivity (APR) data is challenging, the creation of a detailed structural Earth model from borehole images and the results from a 1D inversion algorithm were used to understand geometric effects on the logs qualitatively. The top of the reservoir was modeled as an uneven surface with open bed boundary positions, to represent the undulating nature of the erosional surface between the Lower Burgan and Upper Burgan formations. The used method is an iterative 1D resistivity inversion algorithm and is able to derive more accurate Rt along the lateral and allows to reconstruct and visualize the downhole geological complexity of the Lower Burgan reservoir. Reservoir heterogeneity was investigated by the distribution of flow and storage capacities along the lateral well using effective porosity and he permeability index from magnetic resonance data. The combined interpretation of the reservoir map, Rt and the reservoir heterogeneity highlighted the likely main producing intervals along the well which were placed close to the lithological boundary and hence sufficiently far away from the water transition zone. Other intervals where the well is closer to the water zone are of reduced reservoir quality giving low risk of water production. Based on these insights, suggestions are given to optimizate the completion design to achieve increased and sustained hydrocarbon production.
High angle or horizontal (HA/Hz) wells are commonly drilled to increase reservoir exposure and enhance the overall production. Whereas reservoir navigation highly advance the correct placement of such wells, completion decisions for profit or recovery oriented production optimization require thorough interpretation of available shallow- and deep-reading formation evaluation measurements. Particularly, complex geological environments necessitate the use of reservoir maps and heterogeneity evaluations to understand the likely production behavior. In such applications, formation evaluation measurements from logging-while-drilling (LWD) technology are affected by the relative geometry between well trajectory and the formation. With increasing depth of investigation of the measurements and geological complexity of the reservoirs, these effects become more severe and true properties become uncertain. The multi-propagation-resistivity (MPR) responses show so called polarization horn effects at bed boundaries when beds with a high resistivity contrast are encountered. During the process of inverting these resistivities to obtain true formation resistivity (Rt), inversion algorithms help to reconstruct the complex architecture of downhole formation geometries. This provides a better understanding of the geometrical reservoir complexity and provides insight into the potential future production behavior. Possible corrective actions in production and completion strategies can be derived from such insight. Additional complications like proximity to water transition zone and water coning can be predicted and certain corrective measures, for instance blanking particular zones or placing inflow control devices (ICDs) can be taken, potentially increasing the overall life of the well. This case study presents a horizontal well in a layered Lower Burgan sandstone reservoir of West Kuwait Minagish Field, where a new approach of drilling horizontal sidetracks from abandoned and plugged old vertical wellbores attempted with the purpose of increasing reservoir productivity and tapping into unswept oil. A sidetrack was placed at the roof of the Lower Burgan and navigation while drilling within this complex reservoir was used to stay close to the lithological boundary. Represented by paleo river channel stacked sand bodies, the Lower Burgan formations are overlain by fluvio-tidal sequences of sandstone – siltstone – minor shale alternations of the Upper Burgan with an undulating nature of the lithological boundary. Steering and placing the well in close proximity to this undulating boundary was achieved. The production of this well is exceptionally high with minimum water cut despite a massively increased water transition zone over the last decade. The case demonstrates that an integrated interpretation of the reservoir architecture and heterogeneity along the lateral uncovers the reasoning behind the experienced production. Overall, polarization horns were observed on the propagation resistivity curves. While the interpretation of log artefacts from sole MPR and azimuthal propagation resistivity (APR) data is challenging, the creation of a detailed structural Earth model from borehole images and the results from a 1D inversion algorithm were used to understand geometric effects on the logs qualitatively. The top of the reservoir was modeled as an uneven surface with open bed boundary positions, to represent the undulating nature of the erosional surface between the Lower Burgan and Upper Burgan formations. The used method is an iterative 1D resistivity inversion algorithm and is able to derive more accurate Rt along the lateral and allows to reconstruct and visualize the downhole geological complexity of the Lower Burgan reservoir. Reservoir heterogeneity was investigated by the distribution of flow and storage capacities along the lateral well using effective porosity and he permeability index from magnetic resonance data. The combined interpretation of the reservoir map, Rt and the reservoir heterogeneity highlighted the likely main producing intervals along the well which were placed close to the lithological boundary and hence sufficiently far away from the water transition zone. Other intervals where the well is closer to the water zone are of reduced reservoir quality giving low risk of water production. Based on these insights, suggestions are given to optimizate the completion design to achieve increased and sustained hydrocarbon production.
The precise landing and steering of horizontal wells using conventional mudlogging and Logging While Drilling (LWD) data is a particular challenge for the Lebăda Field, offshore Romania. The use of a new technique of elemental geochemistry analysis (or chemosteering) became an option for the identification of Cenomanian, Turonian–Coniacian–Santonian, Campanian and Eocene strata. This has enabled more accurate placement of the horizontal development wells within the desired reservoir target interval. Geochemical data enabled the identification of chemostratigraphic zones C1, C2, C3 and zone R that correspond to the reservoir section. The application is a result of the geochemical zonation performed using elements and ratios that are sensitive to depositional environment, sea level change, heavy mineral concentrations and siliciclastic input namely: Sr/Ca, Zr/Th, Si/Zr and Si/K. In ascending stratigraphic order, the ratio thresholds of zone C3 are Zr/Th > 11, Sr/Ca > 1.1, Si/Zr < 22 and Si/K < 19, while zone R corresponds to 5.5 < Zr/Th < 11, Sr/Ca < 1.1, Si/Zr > 22 and Si/K > 19. C2 zone is defined by Zr/Th < 5.5, Sr/Ca > 1.1, Si/Zr < 22 and Si/K < 19 and C1 zone is characterized by Si/Zr > 22 and Si/K > 19. The selected geochemical ratios indicate a strong geochemical zonation. In the case of offset wells, 85.9% of the data confirmed the proposed classification and 89.4% for the real-time application case. The zone R shows a strong contrast with the surrounding formations facilitating critical decisions during well placement and geosteering, increasing the reservoir exposure by 28%. The quantitative approach delivered very valuable results, providing a solid foundation to define correlation and well landing intervals. Simultaneously, the cost of the method represents a fraction of the LWD cost and 0.15% of the total project cost, making it very cost effective and a standard approach for future projects.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.