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Abstract The Hibiscus field situated off the North coast of Trinidad is a large, stratigraphically isolated and well-connected gas field which has 14 years of production history. Notwithstanding this extensive production history and overall recovery, a number of key subsurface uncertainties have been identified. The scope of this study was to better understand reservoir complexity and define subsurface risk and opportunity. An integrated and iterative multidisciplinary approach to reservoir modelling was applied in an effort to meet these objectives. A modern suite of workflows such as Monte Carlo Petrophysical analysis, conditioning of models to seismic attributes, experimental design based uncertainty analysis and assisted history matching were used to generate new static and dynamic reservoir models. The key aspect of this workflow was 20+ major static to dynamic model iterations and a large number of deterministic simulations to rank and asses the validity of static concepts. The learnings were subsequently applied to create a robust reference case, static and dynamic uncertainties framed and a static probabilistic uncertainty workflow developed to QC the deterministic case. A full probabilistic assisted history matching exercise on the dynamic model enabled a refinement of the volumetric ranges and provided critical insight through analysis of posterior uncertainty distributions. The iterative workflow allowed concepts to be validated dynamically and it was demonstrated that high quality history matches could be achieved even after the removal of almost all dynamic multipliers – a common issue in simulation models. Significant improvements to pore volume distribution, the use of geologically derived dynamic baffles, and permeability distributions were amongst the key learnings on the static side. The probabilistic dynamic modelling was characterized by a strong GIIP convergence with a reduction of history match error, resulting in a refined volumetric range and better characterization of uncertainty ranges through posterior analysis. The application of modern integrated and iterative workflows to a mature field has better defined uncertainty ranges, understanding of reservoir behavior and overall resulted in a more robust suite of models. Key learnings identified were highlighted to support future reservoir model rebuilds. Ultimately this process has demonstrated the value of revisiting existing datasets in late life assets by generating higher confidence in remaining reserve estimates and business plan forecasts.
A breakthrough in directional drilling data management for large, multiplatform field developments is introduced. The need for accurate directional surveying has been recognized throughout the oil industry and new practice of survey data acquisition and quality control introduced which have resulted in the proliferation of survey and related data. Aspects of this data, namely its safety critical nature, its longevity, its redundancy and its volume, ate discussed. The importance of correct management of this information to safe drilling and the avoidance of well collision are stated. Additional justification is made through the examples of planning and execution of the drilling program.
To date operators have attempted to manage directional drilling data through routes including paper files, mainframe and personal computer systems and contracting to directional drilling service companies. The failure modes of each mechanism are outlined.
The concept of a distributed, networked system of high performance personal computers to support directional performance personal computers to support directional drilling operations is introduced. Using suitable software the operator stores field, structure and slot geometries together with target details, slot to target allocations and all well plans and directional surveys. This database and all relevant engineering tools, for example survey Computation, projection ahead, bottom hole assembly simulations and inter well clearances, are provided both in the office and at the rigsite. The requirement for local data storage to support high performance graphics and the problems of data replication and currency control which this implies are mentioned.
Finally, the utility of extending the rig to office network to provide a data feed to directional drilling contractors and provide a data feed to directional drilling contractors and the importance of technical prequalification of contractors in ensuring they can use this data is stated.
The development of offshore oil and gas from large, multiwell platforms has set new challenges before the drilling industry. High precision, extended reach drilling is required and has provided the impetus to develop steerable drilling system, high accuracy, continous survey tools and other novel technologies, a critical result of which is the proliferation of directional drilling data.
Only a decade ago directional wells were surveyed with highly time consuming photo mechanical tools at relatively large intervals. Today measurement while drilling tools can provide directional surveys requiring virtually no rigtime. Continous survey systems and increased memory capacity allows surveys taken at very close intervals Further, modern survey quality control methods place emphasis on multiply redundant data sets. The net result is a 15 to 20 fold increase in the volume of data collected by a typical surveying program.
The ability effectively to control and exploit this increased volume of data has become a major weakness in many directional drilling campaigns.
CHARACTERISTICS OF DIRECTIONAL DRILLING DATA
Directional drilling data may be characterized as:
safety critical costly to gather having high commercial value high volume long lived
Abstract Since the implementation of the Drilling Performance Department in late 2017, ADNOC Offshore has been able to develop a company performance-oriented culture among the drilling teams. This performance culture is reflected in 25% ILT reduction in 2018 and 12% in 2019. Furthermore, 37 NPT RCA cases were investigated and concluded in 2019, which resulted in 57 actions for tracking and closure. With 5 (five) concessions, 9 (nine) different shareholders, and 39 (thirty-nine) rigs, drilling performance management is challenging. ADNOC Offshore created a centralized Drilling Performance Team to capitalize on this diversity as an opportunity to improve the traditional drilling performance role. This paper describes the team's approach on Drilling Performance and the consecutive result. The team enhances the typical drilling performance role of Key Performance Indicator (KPI) management and reporting by adopting the Performance Opportunity Time (POT) and Root Cause Analysis (RCA) Process. At the same time, the Drilling Performance Team facilitates the flow of information between teams to ensure effective knowledge transfer within such a large organization. The POT concept tackles the well duration reduction through the reduction of Invisible Lost Time (ILT) and Non-Productive Time (NPT). To reduce the ILT, the team took advantage of the extensive technical background in the various drilling teams. Performance improvement initiatives were proposed by taking references from different teams within ADNOC Offshore and evaluating the application in other concession. Other approach is to compare with out-of-company references. For NPT reduction, the innovative approach was to use the HSE Root Cause Analysis (RCA) concept. This RCA process led by the Drilling Performance Team was implemented to standardize the approach and have a systematic investigation analysis. This process resulted in identifying root causes and effective corrective action plans. As per HSE, addressing the root causes of incidents would result in the most significant impact in NPT. This approach also allows an independent and more detailed look on the subjects, where commonly these tasks are done in a limited manner by drilling teams alone with their ongoing operational workload. Finally, results are communicated to the drilling organization through lessons learned portal and technical bulletins.
Abstract ADCO has always been seeking continual improvement to minimise the impact of its drilling operations on the environment and to conserve the desert for future generations. One of the main challenges is proper management of the fluids & solids generated by drilling oil & gas wells. This paper presents the complete solutions adopted to handle the generated waste streams with the improvements in rigs design ("zero" discharge) and the execution of three recent plants:Reconditioning & recycling plant for drilling Oil-Based Mud (OBM). Indirect thermal desorption treatment plant for OBM drill cuttings with 100% recycling of recovered materials which are converted to usable products (i.e., diesel fuel, irrigation water and interlocking blocks). Two dedicated deep disposal wells for waste mud. The outcome of the joint efforts of Drilling & HSE Divisions confirms that all hazardous wastes are being managed with true applications of 3R (Reduce, Reuse and Recycle) to maximise hydrocarbon recovery without noticeable impact on the environment. The new waste management plants are centrally located in the major oil producing fields, thereby reducing hauling distance. These improvements translate in ADCO to minimum disposal and overall costs saving while ensuring compliance with or even exceeding, local environmental regulations. Such global approach of this scale is a first in the Middle East Region and is setting a new benchmark of environmental standards for others to follow. Introduction Drilling oil wells produce large quantities of solid waste drill cuttings and also fluids that must be properly managed to prevent negative impact on human health and the environment. The fluids comprised of drilling mud or brines used in each section of the well. The potential health and environmental hazards are fluids containing large amount of oil (diesel-based mud or OBM) or salts (high salinity water-based mud & completion brines). The solids are the cuttings removed from the hole. They do not present any hazards by their natural minerals but, if generated during drilling with OBM, they are contaminated by 20 to 30 % of oil, which require further treatment before final disposal. Currently, ADCO is producing an estimated 20,000 tons of oily cuttings and about 900,000 barrels of waste fluids have to be disposed off every year. Environmental legislation prohibits disposal of oily wastes into the environment. Waste Management Strategies For many years, ADCO Drilling Division has been increasingly confronted with problems relative to transporting oily cuttings over 300 km from the rig to a designated site for storage and disposal. Expensive OBM (diesel base) was reused few times at other rigs before injection into well annulus. The concept of zero waste discharges from drilling operations was being taken to new levels to develop zero contaminants discharge policy through implementing waste management principle of the three golden rules: REDUCE, REUSE & RECYCLE. The first move is to minimise as much as practical the amount of waste generated ("REDUCE"). Over the years, the following had been implemented in this regard:1. Reduce the hole diameter (less cuttings generated & less mud to be disposed off) by optimising the well casings program for every single well ("light casing program" whenever feasible).2. Eliminate the use of "emulsion" mud (oil added to WBM to reduce weight) in loss circulation zones by using "Aerated mud" (compressed air added to reduce weight).3. Improve the efficiency of the solid control equipment installed on the rigs ("state of the art" shale shakers and rented "Hi-G" dryers & centrifuges) to reduce the need for dilutions & limit the amount of oil on cuttings.4. Strive to reduce OBM usage by assessing & trying new inhibitive water mud systems (Silicate mud for example).