An Integrated Methodology to Locate the Remaining Oil Opportunities in Mature Reservoirs in offshore Sarawak, Malaysia
Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
Cited by 5 publications
References 0 publications
In all development phases of brownfields, identifying sweet spots and the potential remaining oil in place to be recovered is a cornerstone of reservoir management studies and field development operations. This becomes even more imperative for mature waterfloods, where the increasing water cut hinders the ongoing oil production. The current algorithms in waterflood network-based models are capable of building and matching a reservoir model by employing reduced physics data-driven approaches. These schemes estimate the saturation in the entire field; however, the next step in those approaches is adding a fully-integrated and closed loop automated workflow to model the remaining hydrocarbon volumes. The new data analytics approach presented is a systematic bottom-up approach in which the field data, including injection and production, well perforations, pressure history, geological and fluid properties and original oil in place, are integrated. The remaining hydrocarbon thickness and saturation calculated from this methodology are key to target future reactivation and recompletion candidates, therefore potentially reducing CAPEX and OPEX. This automated methodology is robust to handle not only the waterflood but all the development phases. Moreover, it is much faster than the ubiquitous history-matching processes, which require several months on average to be completed. To this end, we have validated the results by a blind test approach to increase the confidence in using the methodology. This proposed workflow greatly improves the assessment capabilities to locate the remaining hydrocarbon resources, and therefore is pragmatic for the prediction of the most prolific future production targets.
In all development phases of brownfields, identifying sweet spots and the potential remaining oil in place to be recovered is a cornerstone of reservoir management studies and field development operations. This becomes even more imperative for mature waterfloods, where the increasing water cut hinders the ongoing oil production. The current algorithms in waterflood network-based models are capable of building and matching a reservoir model by employing reduced physics data-driven approaches. These schemes estimate the saturation in the entire field; however, the next step in those approaches is adding a fully-integrated and closed loop automated workflow to model the remaining hydrocarbon volumes. The new data analytics approach presented is a systematic bottom-up approach in which the field data, including injection and production, well perforations, pressure history, geological and fluid properties and original oil in place, are integrated. The remaining hydrocarbon thickness and saturation calculated from this methodology are key to target future reactivation and recompletion candidates, therefore potentially reducing CAPEX and OPEX. This automated methodology is robust to handle not only the waterflood but all the development phases. Moreover, it is much faster than the ubiquitous history-matching processes, which require several months on average to be completed. To this end, we have validated the results by a blind test approach to increase the confidence in using the methodology. This proposed workflow greatly improves the assessment capabilities to locate the remaining hydrocarbon resources, and therefore is pragmatic for the prediction of the most prolific future production targets.
The paper describes the challenging task of identifying additional production opportunities from a matured oil reservoir with significant production history, commingled production,zones with varying rock properties, and drive mechanisms. The reservoir is having more than 40 years of production history and is currently in a stage of decliningoil production with water breakthroughs in many areas of the reservoir. A new, improved workflow comprisinga classical approach and sector model review wasapplied to understand the recovery efficiency and identify any additional potentials on top of the base profile. The study resultsprovidedan interesting insight into the recovery mechanism and possible additional opportunities in the reservoir. Several recovery ideas like identifying undrained areas, improved completion strategy, the intervention of existing sick wells, and application of EOR processes were applied to estimate the improvementof recovery over the existing field development plan. All components of recovery efficiencies like pore-scale displacement (Ep), drainage (Ed), volumetric sweep (Es), and cut-off (Ec) were reviewed, and the scope for improvement was identified using sector models of the reservoir. The next stage was a fully integrated reservoir study to diagnose the ongoing water flood process and examine strategies to improve areal and verticalsweep. Significant reservoir insights were gained from detailed water influx and reservoir pressure maps and identifying bypassed oil by zone. The last stage was constructing a representative sector model incorporating the latest data for IOR and EOR, which were screened based on the economics criteria. The number of recovery options was evaluated and optimized in the reservoir sector model to select potential opportunities and estimate incremental recovery. Four opportunities were identified that show incremental recovery by improvements in Ep, Ed, and Es for each reservoir zones. The target areas with bypassed oil have been identified for improvement in Ed and Es. Changing from commingled to dedicated completions in a specific shallow, relatively less depleted zone show improvement in Es. Implementing a regular 5-spot pattern water flood instead of random spot water injection in a major shallow zone improves Ed and Es. Lastly, Alkaline Surfactant Polymer (ASP) flooding improves Ep. A detailed roadmap was generated for each recovery option. New polymer-based gels such as preformed particle gels (PPGs), microgels, swelling micron-sized polymers (Bright Water), and pH-sensitive polymers were recommended to mitigate excess water production due to wellbore and reservoir-related challenges. This workflow identified a significant improvement in expected ultimate recovery (EUR) in the mature brownfield and will be applied to other reservoirs in the KOC portfolio. The novelty of the work is an innovative approach to characterizing the existing recovery plan into its underlying efficiencies (Ep, Ed, Es, Ee) and a detailed breakdown of the recovery factor, which led to practical guidance on implementing recovery ideas to improve recovery from the mature oil reservoir.
Locating the Remaining Oil in a Mature Complexly Channelized Clastic Reservoir Using a Combination of Geological and Reservoir Engineering Concepts
Locating the remaining oil (LTRO) in a matured reservoir can be complex and often requires a combination of techniques to achieve the best results. LTRO becomes an uphill task if the reservoir is structurally complex, highly channelized and at a mature stage. The studied reservoir has been on production since 1964 and is at the declining stage of the reservoir life. This paper describes the approach taken to identify additional oil from the areas of un-swept bypassed oil. A methodical approach has been followed to pinpoint those areas of the reservoir where the by-passed oil volumes are expected to be concentrated. The method consists of reviewing historical reservoir performance, fluid-flow dynamics including water movement based on cased and open-hole logs from the wells drilled from time to time, and understanding of the sweep of the reservoir by creating few appropriate sector models. The goal is to comprehend the connection between reservoir actual performance, current sweep and the geological framework of the reservoir. Next step to screen for infill opportunities, EOR opportunities and establish the monetary attractiveness for implementation of these opportunities. The results of this study has shown that the sweep efficiency has not been uniform due to the complexities in development strategy of reservoir consisting of commingled and multiple layer production, peripheral to pattern water injection and water conformance issues etc. Geological complexity also contributed to the non-uniform sweep efficiency. Stratigraphically, the reservoir is subdivided into layered sand and Massive sand units. The layered sand unit consists of shale and coal layers with minimal pressure support and massive sand unit is fully supported by an aquifer. The time lag saturation maps have clearly shown some by passed oil in certain areas of the reservoir. A number of scenarios were worked out to recover these un-swept oil in terms of pore scale displacement and overall sweep efficiency using a representative sector model of the reservoir. A 3D drainage radius workflow has also been applied with simplifying assumptions for production allocation and distribution back into the reservoir. The drainage domains have been defined on the basis of sedimentology and fluid characteristics in combination with quantitative volumetric analysis. Drainage volumes assessment has shown areas where reservoir significant amount of mobile oil volumes is present. The novelty of the new workflow is in the ability to visualize and semi-quantify combined effect of production strategy, reservoir performance, sweep efficiency and underlying geological framework on the drained and undrained areas of the reservoir. This paper provides a systematic methodology for integrating different sources of data and analysis to identify bypassed oil in a mature reservoir and formulate a strategy to recover additional oil.
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.
Contact Info
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Product
Resources
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.
