The United Arab Emirates oil and gas reservoirs are continuously intersected with a growing number of horizontal wells and longer drains at varying bottomhole static temperatures. This results in a variety of naturally flowing and more challenging wells where stimulation is required for sustainable flow. Hence it became important to not only rely on plain acid systems for production gain, but to also include more sophisticated acid stimulation systems that can provide improved results in more challenging environments where plain acid may be found lacking. These results were recently achieved via the introduction of single-phase retarded acid (SPRA) as well as viscoelastic diverting acid (VEDA) in inactive wells offshore. The application of SPRA and VEDA was subsequent to extensive laboratory testing including core flow tests, solubility tests, and emulsion tendency testing to the performance of these blends against existing acid recipes such as plain HCl and polymer-based diverting acid. These tests proved that a combination of SPRA and VEDA would allow maximizing lateral coverage in heterogenous reservoirs due to the chemical diversion capabilities from thief zones without imposing further damage that polymer-based diverted acids may cause. The combined SPRA and VEDA would also enhance acid wormhole penetration due to the reduced rate of reaction caused by acid retardation. Such tests were supported with software simulations that provided acid dosage, pumping rate, and pumping method sensitives. Proposing SPRA and VEDA at higher pumping rates enabled the delivery of previously unattainable production influx at sustainable wellhead pressures. In addition, 28% acid content typically used for dolomitic reservoirs was considered unnecessary as 20% retarded acid proved sufficient in such environments. This allowed bullheading treatments, which was previously not possible due to the restriction on pumping 28% acid content across wellheads to avoid causing corrosive damage. Other treatment parameters such as volumes, rates, and acid/diverter sequence and ratio were also adjusted for optimal wormhole penetration across all zones using a fit-for-purpose carbonate matrix acidizing modeling software. The success of SPRA and VEDA was clear in post-treatment evaluation for the cases of previously shut-in wells. These wells were able to produce sustainably at the required tubinghead pressure (production line pressure) after unsuccessful attempts to flow prior to stimulation. The novelty of this paper is the assessment between legacy carbonate stimulation results in UAE using plain HCl acid and polymer-based diverting acid (PDA) and using SPRA and VEDA in shut-in or inactive wells. It also highlights the game-changing solutions that suit the increasing challenges observed in offshore inactive wells including well placement, lithology, bottomhole static temperature, and permeability contrast.
Development of giant offshore carbonate field with more than 400 oil producers and 300 water injectors are very complex without proper production optimization tool to reach sustainable production and optimize the cost of the investment for future development. Construction of IAM model for short term optimization purposes brings vital outcomes which can identify the short and long term optimizations scenarios and as a consequences reduce the investment with the maximum outcome of production within the reservoir management guidelines of the field. Integrated asset modelling tool (PSO-production system optimization tool Prosper+Gap) is ideal tool which can provide the best production optimization results to develop the giant field with all reservoir guidelines and production system bottleneck. One of the main achievement of integrated asset model (PSO) for a giant carbonate oil field is the fact that its fully compositional model which allows to track oil composition change at any point of the surface facility, which is critical for fields under secondary recovery mechanisms with water and gas injection.
The paper discusses the pilot project in ADNOC Offshore to assess the Autonomous Inflow Control Device (AICD) technology as an effective solution for increasing oil production over the life of the field. High rate of water and gas production in horizontal wells is one of the key problems from the commencement of operation due to the high cost of produced water and gas treatment including several other factors. Early Gas breakthrough in wells can result in shut-in to conserve reservoir energy and to meet the set GOR guidelines. The pilot well was shut-in due to high GOR resulted from the gas breakthrough. A pilot project was implemented to evaluate the ability of autonomous inflow control technology to manage gas break through early in the life of the well spanned across horizontal wellbore. And also to balance the production influx profile across the entire lateral length and to compensate for the permeability variation and therefore the productivity of each zone. Each compartment in the pilot well was equipped with AICD Screens and Swell-able Packers across horizontal open hole wellbore to evaluate oil production and defer gas breakthrough. Some AICDs were equipped with treatment valve for the compartments that needed acid simulation to enhance the effectiveness of the zone. The selection factors for installing number of production valves in the pilot well per each AICD was based on reservoir and field data. Pre-modeling of the horizontal wellbore section with AICD was performed using commercial simulation software (NETool). After the first pilot was completed, a detailed technical analysis was conducted and based on the early production results from the pilot well showed that AICD completions effectively managed gas production by delaying the gas break through and restricting gas inflow from the reservoir with significant GOR reduction ±40% compared to baseline production performance data from the open hole without AICD thus increasing oil production. The pilot well performed positively to the AICD completion allowing to produce healthy oil and meeting the guidelines. The early production results are in line with NETool simulation modelling, thereby increasing assurance in the methods employed in designing the AICD completion for the well and candidate selection. This paper discusses the successful AICD completion installation and production operation in pilot well in ADNOC Offshore to manage GOR and produced the well with healthy oil under the set guidelines. This will enable to re-activate wells shut-in due to GOR constraint to help meeting the sustainable field production target.
Today, in a matured developed field, reservoir management is challenging due to poor seismic resolution at reservoir level. Whereas overburden geology further deteriorate seismic quality due to foot prints, observed at reservoir level. Overburden geology is a key challenge for reservoir characterization and may mislead faults and fractures interpretation, identification of rock properties and distribution of fluids. In this paper we tried to integrate both diffraction and reflection data to improve seismic resolution to delineate reservoirs and non-reservoirs zone with drilling and well data. Seismic data Seismic data was acquired using OBC technique. PreStack Time Migration processing was performed in 2002, 2016 and psdm migration was performed in 2018 for structural interpretation. However data quality for reservoir characterization was affected by the hardness of the seafloor and anomalies in the overburden. These challenges are currently being addressed through diffraction imaging. In 2022, Diffraction imaging is performed for 10×10 KM2 pilot area, due to which we were able to delineate karstic feature in detail and faults at reservoir.
Objective/scope Demonstrate technology effectiveness following improvements to system to increase robustness and refine operations following the initial Pilot Well deployed January 2016. The first Abu Dhabi Offshore well was deemed to be a success (reference SPE-183465-MS) despite deployment challenges during the lower completion phase. There was an opportunity to address these challenges for the second well, in the deployment of well -1 which from an operational perspective was textbook. In the search for an improvement to the Productivity index (PI), multi-lateral acid jetting technology was adopted as a more effective approach to typical drainage methods. With conventional stimulation techniques being limited in effectiveness and often leaving significant volumes of recoverable reserves out of reach, an alternative approach was required to create new connections within the reservoir. This technology effectively creates connections to layers previously separated by very tight, low permeability barriers to dramatically increase recovery factors across carbonate reservoirs. Method, procedures, process In a single multi-rate pumping sequence, needles were extended to create channels into the reservoir layers, using acid jetting technology to achieve vertical connectivity and improve production rates. Currently, up to 60 subs can be deployed in a signle well bore. With each sub capable of deploying 4 needles at 90 degrees perpendicular to the wellbore and up to 40 feet in length, multiple micro-laterals are created throughout the reservoir. During this case study, 10 sub-assemblies of the multi-lateral acid jetting technology system were installed, creating 40 micro-laterals, which significantly improved access to reserves. These laterals remain in the well, essentially leaving a permanently installed lower liner with full bore access to TD. Results, observations, conclusions Following successful adoption of this technology, the well has been producing for a year with positive results. Multi Rate test/PLT/Memory Gauge data all confirms a productivity index increase of 120%. This paper describes the process of candidate selection, completion design, operational challenges, deployment, post job analysis, system improvement and lessons learnt. Additional Information Multilateral acid jetting technology has evolved and improved over recent years and the primary differentiators highlighted in this paper are as follows: The continuous enhancement of multi-lateral acid jetting technology is playing a key role in driving increased efficiency in field development planning. By reducing the total well requirement for the reservoir, whilst simultaneously increasing recoverable reserves, the technology is at the forefront of facilitating the future state of field development.
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.
hi@scite.ai
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.