Search citation statements
Paper Sections
Citation Types
Year Published
Publication Types
Relationship
Authors
Journals
Taking the North Saertu Development Area (NSDA), La-Sa-Xing oilfield in Daqing, China as an example, this paper presents best practices to improve mature field waterflood recovery. Placed onstream in 1963, development of the multi-layer sandstone reservoir experienced three-round infill drillings, EOR polymer flood and ASP flood. Strong reservoir heterogeneities, producing at water-cut >90% starting in 1999, various IOR/EOR activities and several well-pattern types overlapping vertically led to extreme challenges for further improving waterflood recovery. This paper first introduces the general reservoir geology, reservoir heterogeneity characteristics, fluid properties and reservoir conditions, followed by illustrating its 60-year development history and key IOR/EOR activities implemented. The focus of this paper is to illustrate the strategy, fit-for-purpose technologies, and effective reservoir management practices to further improve waterflood recovery at extra-high water-cut development stage. The discussed improved recovery practices are based on deliberate reservoir characterization and remaining oil study by integrating wireline logging, 3D seismic, production logging, sealed core data, production performance data and various other performance monitoring data. Several pilots on water-controlling, producing by-passed thick pay sands as well as re-arranging individual well pattern were conducted, providing a basis for field-wide application. Key strategy and technologies adopted are: 1) subdivision of individual injection-production interval and reduction well spacing; 2) improving water injection at individual well pattern and single flow-unit level; 3) combining waterflood and polymer/ASP flood by utilizing the same wellbore or well pattern to develop marginal pay sands in a cost-effective way; 4) improved zonal water injection by reducing individual injection thickness and permeability contrast within the injection interval; 5) improved injection profile through profile modification; 6) integrated approach to mitigate injected water channeling in thick pay sand; 7) cyclic water injection; 8) well drilling along fault plane producing by-passed oil; and 9) horizontal wells producing poorly swept or attic oil. The IOR and reservoir management activities have successfully arrested production decline, mitigated water-cut rising, leading to an increased waterflood recovery by >2.5%. Mainly implemented at development stage with extra-high water cut of 92%-95%, the integrated IOR and reservoir management activities discussed in this paper are all feasible, proved technically successful and cost-effective. These practices provide a road map and solutions for extending oilfield life or rejuvenation of a waterflood mature oilfield.
Taking the North Saertu Development Area (NSDA), La-Sa-Xing oilfield in Daqing, China as an example, this paper presents best practices to improve mature field waterflood recovery. Placed onstream in 1963, development of the multi-layer sandstone reservoir experienced three-round infill drillings, EOR polymer flood and ASP flood. Strong reservoir heterogeneities, producing at water-cut >90% starting in 1999, various IOR/EOR activities and several well-pattern types overlapping vertically led to extreme challenges for further improving waterflood recovery. This paper first introduces the general reservoir geology, reservoir heterogeneity characteristics, fluid properties and reservoir conditions, followed by illustrating its 60-year development history and key IOR/EOR activities implemented. The focus of this paper is to illustrate the strategy, fit-for-purpose technologies, and effective reservoir management practices to further improve waterflood recovery at extra-high water-cut development stage. The discussed improved recovery practices are based on deliberate reservoir characterization and remaining oil study by integrating wireline logging, 3D seismic, production logging, sealed core data, production performance data and various other performance monitoring data. Several pilots on water-controlling, producing by-passed thick pay sands as well as re-arranging individual well pattern were conducted, providing a basis for field-wide application. Key strategy and technologies adopted are: 1) subdivision of individual injection-production interval and reduction well spacing; 2) improving water injection at individual well pattern and single flow-unit level; 3) combining waterflood and polymer/ASP flood by utilizing the same wellbore or well pattern to develop marginal pay sands in a cost-effective way; 4) improved zonal water injection by reducing individual injection thickness and permeability contrast within the injection interval; 5) improved injection profile through profile modification; 6) integrated approach to mitigate injected water channeling in thick pay sand; 7) cyclic water injection; 8) well drilling along fault plane producing by-passed oil; and 9) horizontal wells producing poorly swept or attic oil. The IOR and reservoir management activities have successfully arrested production decline, mitigated water-cut rising, leading to an increased waterflood recovery by >2.5%. Mainly implemented at development stage with extra-high water cut of 92%-95%, the integrated IOR and reservoir management activities discussed in this paper are all feasible, proved technically successful and cost-effective. These practices provide a road map and solutions for extending oilfield life or rejuvenation of a waterflood mature oilfield.
Field X is one of largest oil fields in Brunei producing since 1970's. The field consists of a large faulted anticlinal structure of shallow marine Miocene sediments. The field has over 500 compartments and is produced under waterflood since 1980's through 400+ conduits over 50 platforms. A comprehensive review of water injection performance was attempted in 2019 to assess remaining oil and identify infill opportunities. Large uncertainties in reservoir properties, connectivity and fluid contacts required that data across multiple disciplines is integrated to identify new opportunities. It was recognized early on that integrated analysis of surveillance data and production history over 40 years will be critical for understanding field performance. Hence, reviews were first initiated using sand maps and analytical techniques. Tracer surveys, reservoir pressures, salinity measurements, Production Logging Tool (PLT) were all analyzed to understand waterflood progression and to define connectivity scenarios. A complete review of well logs, core data from over 30 wells and outcrop studies was carried out as part of modelling workflow. This understanding was used to construct a new facies-based static model. In parallel, key dynamic inputs like PVT analysis reports and special core analysis studies were analyzed to update dynamic modelling components. Prior to initiating the full field model history matching, a comprehensive impact analysis of the key dynamic uncertainties i.e., Production allocation, connectivity and varying aquifer strength etc. were conducted. An Assisted History Matching (AHM) workflow was attempted, which helped in identifying high impacting inputs which could be varied for history matching. Adjoint techniques were also used to identify other plausible geological scenarios. The integrated review helped in identifying over 50 new opportunities which potentially can increase recovery by over 10%. The new static model identified upsides in Stock Tank Oil Initially in Place (STOIIP) which if realized could further increase ultimate recoverable. The use of AHM assisted in reducing iterations and achieve multiple history matched models, which can be used to quantify forecast uncertainty. The new opportunities have helped to revitalize the mature field and has potential to almost increase the production by over 50%. A dedicated team is now maturing these opportunities. The robust methodology of integrating surveillance data with simulation modelling as described in this paper is generic and could be useful in current day brown field development practices to serve as an effective and economic manner for sustaining oil production and maximizing ultimate recovery. It is essential that all surveillance and production history data are well analyzed together prior to attempting any detailed modelling exercise. New models should then be constructed which confirm to the surveillance information and capture reservoir uncertainties. In large oil fields with long production history with allocation uncertainties, it is always a challenge for a quantitative assessment of History match quality and infill well Ultimate Recovery (UR) estimations. Hence a composite History Match Quality Indicator (HMQI) was designed with an appropriate weightage of rate, cumulative & reservoir pressure mismatch, water breakthrough timing delays. Then HMQI parameter spatial variation maps were made for different zones over the entire field for understanding and appropriately discounting each infill well oil recovery. Also, it is critical that facies variation is properly captured in models to better understand waterfront movements and locate remaining oil. Dynamic modelling of mature field with long production history can be quite challenging on its own and it is imperative that new numerical techniques are used to increase efficiency.
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
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.