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Collaborating Authors
Abstract Unplanned Sustained Annulus Pressure (SAP) in the A Annulus (sometimes referred to as the tubing/casing annulus or TCA), is the most common of all well integrity management challenges. Typically, this is as a result of a failure in a well integrity barrier envelope element / component. Monitoring for this situation is of critical importance because it generally means the ‘double barrier' well integrity policy that most OPCO's follow is breached. Depending on the nature of the SAP, it is often necessary to close in the well pending workover. In other cases, where a workover is not economically viable, the well may be prematurely abandoned. Alternatively, the wells may remain in operation ‘under dispensation'. In the cases where wells continue to operate ‘under dispensation' increased manpower is required for monitoring and manual bleed down. This is to avoid the SAP exceeding the Maximum Allowable Annulus Surface Pressure (MAASP) and to monitor for any changes in the nature of the SAP. In addition to the obvious increased risks associated with a pressurized annulus, where only a single barrier to flow exists, other significant risks are also, often unknowingly, accepted. This is due to the way annulus pressure is typically measured and recorded. These annulus pressure measurement risks and a field proven solution to mitigate them, are described in this paper. The paper also describes a field proven solution to the challenge of managing wells with unplanned SAP in the A annulus. It involves retrofitting technologies, which were originally developed for use in gas lifted wells, where the wells are designed to cater for planned SAP in the A annulus. A leak from the A annulus of a gas lifted well would usually pose a higher risk of an explosion than would be the case from a non gas lifted well with SAP in the A annulus. Consequently, the paper therefore concludes that the approach used to provide a double barrier envelope to prevent a gas release from the A annulus in gas lifted well, can therefore also be applied in non gas lifted wells, where the SAP in the A annulus is unplanned. As a result, the risks of operating wells ‘under dispensation' are reduced. Wells which previously had to be killed or plugged pending workover or abandonment, may also be reclassified as ‘capable of operating under dispensation'. The paper describes how the system can be automated, to facilitate autonomous annulus pressure monitoring and bleed off without manual intervention. It goes on to discuss how the nature of the SAP can also be tracked and the sampling frequency optimised. Finally the paper describes how these technologies can be retrofitted to existing wells. This is possible, without the need for workover, annulus depressurization, wireline intervention or significant wellbay piping modifications.
A Systematic Approach to Monitoring and Management of Annulus Pressures
Srivastava, Manish (ADNOC Offshore) | Ali, Abeer A. (ADNOC Offshore) | Alshehhi, Ali S. (ADNOC Offshore) | Kumar, Amit (ADNOC Offshore) | Spuskanyuk, Oleksandr (ADNOC Offshore) | Abdulhai, Walid M. (ADNOC Offshore) | Gan, Chee Lam (ADNOC Offshore)
Abstract Annuli pressure if not controlled and managed may result in uncontrolled release of high-pressure hydrocarbon fluids from reservoir to the surface. This may cause loss of life, damage to environment, and tarnish the reputation of the company. In this paper, two potential pathways for reservoir fluid to reach the surface through annuli have been examined, and recommendations were provided to diagnose and manage annulus pressures within safe operating limits. Integrated well integrity assessment to diagnose the root-cause of annulus pressure involved using various tools to measure key parameters needed to make an accurate assessment of root-cause of annulus pressure. For example, thermal numerical models and lab tests were conducted to simulate thermal effects in the well and analyze annulus fluid samples, respectively. Furthermore, echometer was used to measure fluid-level in the annuli, whereas logging tools such as spectral noise, high-precision temperature etc. were used to identify source of any reservoir fluid ingress. Multiple diagnostic, surveillance and management workflows for outer and inner annuli have been developed. Experiences in implementing these workflows for hundreds of wells in the field have been described and lessons learned have been discussed. Special attention has been paid to the cases with confirmed or suspected lost barriers. Appropriate, cost-efficient levels of diagnostics have been selected and employed to ensure safe operations. Decision trees on how to manage wells with annulus pressures have been discussed, in particular related to planning and execution of pressure bleed-offs, annulus top-ups with heavier fluids, etc. Based on decision trees, cost-efficient levels of diagnostics have been selected and employed to ensure safe operations. This work provides insights on various tools to diagnose and cost-effectively manage the pressure in the annulus by combining the available tools and software. Company-specific annulus pressure management strategies have been developed and successfully employed to safely operate wells with annulus pressure.
Case Study of a Novel Autonomous Real-Time Monitoring, Control and Analysis System, to Maximize Production Uptime on Sustained Annulus Pressure Wells, While Improving HSE and Compliance with Double Barrier Well Integrity Policies
Dsouza, Rylan Paul (Petroleum Technology Company) | Cornwall, Rachelle Christine (ADNOC Onshore) | Brodie, Alan David (Petroleum Technology Company) | Patela, Pedro (Petroleum Technology Company) | Daghmouni, Hamdi Bouali (ADNOC Onshore) | Arakkalakkam, Mohammad Hariz (ADNOC Onshore) | Boni, Venkata Praveen Kumar (ADNOC Onshore) | Khan, Asif Khan Haq Dad (ADNOC Onshore)
Abstract This paper describes an innovative solution for the safe and effective management of wells with unplanned sustained annulus pressure (SAP). The solution restores double barrier integrity in the well and provides reliable real time annulus pressure and temperature data. It also has the functionality to autonomously bleed-off the annulus pressure at a pre-determined set point. As a result, the nature and severity of the SAP can be better understood, and in many cases wells that would otherwise have been closed in awaiting workover can remain in production.
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > Asia Government > Middle East Government (0.49)
- Well Drilling > Wellbore Design > Wellbore integrity (1.00)
- Well Completion > Well Integrity (1.00)
- Reservoir Description and Dynamics (1.00)
- (4 more...)
- Information Technology > Architecture > Real Time Systems (1.00)
- Information Technology > Communications > Networks > Sensor Networks (0.31)
New Techniques of Through-Barrier Diagnostics to Improve Integrity Management Decisions in Reservoir Development of Complex Reservoirs
Gibrata, Muhammad (Dragon Oil) | El Sayed, Mohamed (Dragon Oil) | Naguib Hashem, Mohamed (Dragon Oil) | Aslanyan, Irina (TGT) | Minakhmetova, Roza (TGT) | Skutin, Vasiliy (TGT) | Abasher, Doha (TGT) | Abu-Rahmoun, Husam (TGT)
Abstract The mature oil field in the Caspian Sea was originally discovered in the 1960’s and more than 100 wells were drilled in the field. When Dragon Oil inherited the field in the 90s, it had a well stock of varying issues and complexities that required a full field well integrity review to cover the entire well lifecycle. Dragon Oil had a field-wide detailed well status report demonstrating that many wells had integrity problems related to sustained annulus pressure (SAP) in a variety of annuli, which, when risk-ranked, clearly identified those wells that needed intervention. This paper will demonstrate the cases where slickline-conveyed cased-hole memory logging tools were run at three different well lifecycle stages: Well drilling - to detect the shallow water or gas source and perform a remedial job Production operations - to identify sustained annulus pressure sources so remedial solutions could be prepared to cure high risk wells Plug&Abandonment planning - to provide a status report of downhole well conditions so that a cost-effective abandonment programme could be planned and executed. In each of the above cases, the data collected during logging operations provided a clear identification of the related well issues and was sufficient to allow detailed planning and execution of remedial jobs and abandonment operations.
- Asia > Middle East > UAE (0.28)
- North America > United States > Texas > Dawson County (0.24)
Holistic Annulus Investigation as a Tool to Assure Well Integrity in a Deep Water Environment
Ajayi, Ayotunde (Shell Nigeria Exploration and Production Co.) | Mamman, Saratu (Shell Nigeria Exploration and Production Co.) | Agbahara, Chidi (Shell Nigeria Exploration and Production Co.) | Udo, Nsikak (Shell Nigeria Exploration and Production Co.) | Karunwi, Akinola (Shell Nigeria Exploration and Production Co.) | Ogunsina, Oluseye (Shell Nigeria Exploration and Production Co.)
Abstract The physical integrity of a well is a lynchpin for any oil and gas company to achieving it's production target safely. In a deep water field with subsea wells, ensuring the physical integrity of the wells is paramount. It is given key focus because of the high value of the investment, difficultly in accessibility and the sensitivity of the surrounding environment. Subsequently, it is important that all subsea wells in a deepwater field with observed excursions outside of it's annulus limits are investigated in systematic manner to prevent any incidents or loss of containment. Field X is an offshore deep water asset in the Gulf of Guinea. The field is developed by subsea wells tied back and producing to an FPSO. It's subsea wells are drilled and completed in ca 3300 ft of water targeting hydrocarbon bearing reservoirs, with reservoir depths ranging from 7600 ftss to 10200 ftss. The wells were completed with the full capability to monitor the pressure, temperature and to control the xmas tree valves remotely from the FPSO. The maximum allowable annulus surface pressure (MAASP) and the minimum annulus pressure (minAP) limits are set for each well based on the stress modeling of the expected operating conditions during the life of the well and the casing and tubing stress and tensile limits. The MAASP, MAWOP and MinAP annulus pressure limits are part of the well and reservoir operating envelope (OE) which specify the operating points and the boundaries governing the safe production. Since the start of production in the mid 2000's, the asset team has observed that several wells exceed the set annulus pressure limits in the operating envelopes. These non-routine excursions, are detected automatically on the FPSO by the DCS and reported on the Processbook and the electronic well integrity management system portal (e-WIMS). These exceptions are an indication of a potential problem or leak within the well or a valve in the subsea xmas tree. To determine the root cause of the annulus pressure excursion or the possible leak paths/points, an annulus investigation is be conducted on the well. The annulus investigation is a workflow that starts with a preliminary risk assessment of the observed excursion. Thereafter, a systematic workflow is followed, which requires a comprehensive work program or FMS to determine the root cause of the suspected leaks. After the investigation is executed in the field, the results are analyzed and a follow-up risk assessment is held to determine the mitigating actions to manage the well safely. This paper presents the gamut of annulus problems observed in the wells in field X, the premise for executing an annulus investigation, the workflow and the results and the mitigating actions taken to minimize the risk of incident. Well integrity is an important aspect of managing an oil and gas asset. This paper demonstrates how annulus investigations are executed as a effective tool in a process to ensure the physical integrity and safety of these wells.