The offhsore oil field, situated offshore Abu Dhabi, has been operated by TOTAL for nearly 40 years. At the time of development it was estimated that recovery of the original oil in place would be recovered and that the field would be abandoned shortly. Since the early 1970s, however, many new innovative technical solutions have been employed to improve recovery and maintain economic production; one such technology has been the progressively complex multi-lateral wells that have been successfully used to drain smaller and smaller pockets of residual oil. As a consequence, recovery today is high and with certain reservoir layers reaching a record recovery factors in a carbonate reservoir.
The Upper reservoir, concerned by the advanced drilling technology, is composed of alternate layers of anhydrite and dolomite. The numerous horizontal barriers created by the anhydritic beds have led to the presence of 5 different oil-water contacts and variable, but generally poor, natural aquifer pressure support. In addition, the pressures and oil API were different and caused independent dynamic response to the production. The intermittent tight, intermediate and permeable layers also further complicated the development. Due to all these difficulties, the recovery factor is less compared to other reservoirs in the field.
Initially the production from the reservoir was with vertical wells but then deviated wells began to be drilled from the fixed platforms. The pressure support was provided by peripheral water injectors. The deviated wells were useful in targeting remote areas of the reservoir but, since the layers were thin, the exposure to the reservoir was limited. Also, this resulted in the permeable layers being more developed than the tight layers due to the commingled production.
To improve the oil recovery, an innovative technology was applied for the first time in 1997. TOTAL introduced the drilling of multi-horizontal drains. The completions were innovative allowing for gas lift and selective, independent production of each drain as necessary. Depending on the physical properties of the targeted layer, the proximity of nearby wells and drilling feasibility, the drain lengths ranges from 300m to 1000 m.
Since 1997, over 30 Multi-lateral wells have been drilled with up to 6 branches per well and targeting layers as thin as 1.5m. Many wells have used up "dead?? slots, thus adding incremental reserves with limited impact on existing facilities. After 14 years of experience drilling such wells, this paper provides a Case Study highlighting the production benefits as well as a review of some of the technologies that were introduced to achieve them.
TOTAL Abu Al Bukhoosh (TABK) has initated a well sequence with the Perro Negro 2 rig (PN2); a Jackup MODU. The rig contract started early January 2010 and may be extended till end of 2015, based on HSE and technical performances.
Since day one, it has been decided to boost the HSE performance with robust Management Leadership, Engineering HSE and ergonomics, and working on the Employees behavior. This well known drilling industry approach has been augmented by TABK decision to surpass general standards. Two additional Safety Officers providing 24 hours HSE coverage were hired by the Rig Contractor. One Rig Site Safety Advisor was mobilized by TABK. Their constant presence provides a close working relationship with the front line workers and Team Leaders. Several audits and ‘'360 Deg'' HSE initiatives were able to increase the HSE awareness of all.
PN2 has no recordable incident since 900 days. Initially, the HSE initiative and audit plans were based on the experience of the Managers offshore and onshore and not really linked to a formal ranking of the risks.
New sophisticated tools are being developed in the Oil & Gas Industry to rank risks: For example, TABK HSE and Asset Integrity Departments are working on Technological Risk Assessment and Threat Registers. Multi-yearly mitigation measures and action plans are proposed. The well recognized ‘'likelihood-consequences'' matrix has been adopted also for rig operations. It allows for highlighting the risks per area and the main population involved, ranks the areas per overall risk, and thus develops an audit/frequency plan related to those risks.
With such structured and formalized HSE strategy, risks are well captured, type and frequency of the audits are straight forward, and barriers are implemented for a residual risk ALARP.
This paper will explain in greater detail how this was achieved, the challenges that were encountered during the implementation of the tool, and how the Team intends to continue to add value in such a new HSE culture orientation.
TOTAL ABK has been operator of the offshore Abu Dhabi field, Abu Al Bukhoosh (ABK) for nearly 40 years. As the field has matured, the field has increased in complexity as has the volume of data, the number of users and the requirements for data handling. With the constant movement of personnel within the affiliate it is absolutely essential that the gold mine of data is kept up-to-date with new users confident that historical data has been reliably stored. When the field came on stream in 1974, slow, unwieldy computer technology had only just begun to emerge in some of the larger companies but technology has advanced dramatically since then and the power of IT is now revolutionizing the way we perceive and use data. The challenge, today, is thus to improve efficiency of storing and accessing data, which is continuously required for interpretative engineering work.
Efficient data management along with a user-friendly interface can help overcome this challenge. The concept of a "Geo-Information?? Department was invented by TOTAL to manage the company's data efficiently, so their engineers could focus on field studies. Capturing the data from its birth, checking its quality, classifying it and finally storing it with standard templates is the key to data management. The workflow and the quality control check for each data point and type is different.
Once data is stored in a database, a user-friendly interface (Integrated Reservoir Tool, IRT) with single access point is used to access, visualize and extract the data efficiently. IRT with different charts for various data types enables users to make quick analysis and decisions. Some automated data extractions are also made simple.
By having a master database, the quality and uniqueness of the data is guaranteed. Moreover, the historical data recovery is centralized. If the data is not present in the master database, the user can be confident that the data does not exist. User can access and extract the data by themselves without any support.
The beauty of the system is that it is an IT system built by IT specialists but designed and used by geoscientists. The database is no longer a "black box??, it is a living system accessed every minute by geoscientists both onshore and offshore.
TOTAL Abu Al Bukhoosh (TABK) is an offshore Oil and Gas facility producing an average of 100 000 boepd. This activity is inevitably associated with environmental impacts and in particular with atmospheric emissions of green
PEMS are software based continuous monitoring systems that are using process data such as, but not limited to, fuel consumption, power output, combustion exhaust temperature, etc to predict air pollutant emissions. PEMS models were designed, tested, and certified in compliance with current best international practices and now allows TABK to continuously quantify the emissions of nitrogen oxides (NOx), sulphur dioxide (SO2), carbon monoxide (CO), oxygen (O2) and carbon dioxide (CO2) on its offshore facility.
Results indicate that atmospheric emissions have a direct correlation with operation of the emission source; load, firing temperature, fuel flow and quality. Calibrated emissions models utilize measurements from existing instruments already available in the site control system (DCS) and calculate, display, trend and report the emissions of NOx, CO, O2, SO2, CO2.
PEMS reporting solution was granted approval by ADNOC, the local regulator, and is recognized as being a Best Available Technique for UAE Integrated Pollution Prevention and Control emissions compliance reporting. Furthermore, this continuous quantification of the main air pollutant emissions can now support adequate modeling and assessment that enables accurate air quality forecasting and can support any development of cost-effective abatement philosophy and strategy with clear and precise scientific information.
Committed to zero tolerance to hydrocarbon release, TOTAL ABK leak task force has developed and implemented an optimized tool for systematic quantification, recording, reporting, identifying root cause and perform trend analysis for all hydrocarbon releases. The innovative solution delivered is a powerful excel datasheet: the leak declaration register. This document is an incredibly simplified electronic tracking tool that integrates creative know how in many aspects of tackling leaks follow up, classification and standardization. The following key improvements were obtained:
• An accurate and consistent identification of the leak rate, as well as key factors such as leak size, pressure, category of the leaking equipment, location , etc,
• A precise quantification of hydrocarbon quantity released independently of the fluid type,
• A precise mitigation and corrective measures with key person in charge as well as a follow-up of repair status
• A very detailed classification of the leak but also a standardised root cause identification (degradation of material properties, fatigue, corrosion, inadequate installation or procedure) allowing sound reporting,
• The ability to perform reliable trend analysis and, based on the current year available, the data allowed a clear focus on selected platforms where a significant higher number of gland leaks was recorded. Thanks to this, an optimized maintenance schedule was delivered, enhancing operational efficiency.
• A systematic application for classification and reporting.
By consolidating hydrocarbon release data collection, data analysis and reporting, the learnings and improvements can be greatly facilitated. Benefits are to standardize the classification of leaks, improve reporting and trend analysis by having consistent approach.
Working on offshore installations involves rotation scheme that are very variable; 4 weeks on-4 weeks off, 6 weeks on -3 weeks off, 8 weeks on- 4 weeks off, or even 20 weeks on-4 weeks off.
At TOTAL ABK, we are convinced that human factors make a significant contribution to Health and Safety and that further improvements in HSE performance, over and above those resulting from improvements in engineering and management systems, will only come about if human factors are taken into account.
Committed to tackle this issue and sensible to the increasing international evidence that long working patterns can lead to adverse health effects such as demotivation, anxiety, biological rhythms disturbances, and/or negative sleep patterns, TOTAL ABK Management has decided to implement a comprehensive shift work life style training program and to optimize rotation schemes of key personnel. A thorough assessment was done and the longest rotation periods were reduced without salary cuts on all the employees.
Although the effects of extended work hours and shift patterns on performance is well documented in the international HSE literature, the local expectations are not set in terms of the maximum duration of work assignment in remote locations. Therefore efforts were undertaken by TOTAL ABK to enforce these optimized rotations to key contractors who responded positively.
TOTAL ABK Commitment to reduce the likelihood of accidents and ill health is paramount and the continuous strive to eradicate any latent sources of risk to Health and Safety of its personnel has been successfully demonstrated with this initiative.
The best way to reduce risk is to eliminate it all together. Total Abu Al Bukhoosh (TABK) is a mature field being operated for many years, yet new technologies and innovative solutions are constantly fed into our operations and maintenance toolbox. Through use of an innovative approach for maintenance activities, Total ABK reduced by 90% the overall manhours of exposure during an offshore flare tip replacement.
TABK compared two alternatives for the flare tip replacement program. The first was to perform the operation using conventional heavy load crane barge methodology. The activity is performed by landing the barge near the flare header and removing the tip with the crane. The second option was to perform the replacement by helicopter rather than crane barge, using the "long line" flying technique (sometime referred to as "Vertical Reference"). This methodology is very innovative and is performed by expert crews only as it requires experienced hands, high-tech equipment and specialized guidance tools.
There are many benefits using the helicopter approach, most impressive of which is the overall reduction in workplace exposure. Total hours for the helicopter operation including on-site prep time was 123 hours, versus an estimated 2880 hours for the crane barge approach. Additional benefits include reduced down time (two field days vs. three weeks), reduced chance of weather delays and up to 7 times less CO2 emissions. HSE performance improvement doesn't mean additional cost as this approach was 1/3 of the cost of the crane barge approach.