Some new and further developments of offshore fields in Abu Dhabi expect to exploit extended reach drilling (ERD) whereby large numbers of wells are drilled from drilling centers on artificial islands or large platforms. The wells will also have increasingly long reservoir sections (up to 10000 ft), so-called maximum reservoir contact or MRC wells. Artificial islands may have a much larger well capacity (200 or more wells) and larger slot separations (15-30 ft) than platforms but optimal well allocation and sequencing is far more complex than for single cluster platforms. Large numbers of wells (producers and injectors) require multiple clusters separated by 100-200 ft in order to accommodate rig layouts, allow rig movements and access to all slots. Cluster and slot layouts also impact and are impacted by facilities layouts of manifolds and flow lines.

This conceptual study addresses the subject field which has a current expected operating life of more than 100 years, which exceeds the life of the existing facilities. As an alternative to continuing development with Well Head Platform Towers (WHPT’s), the concept of artificial islands holding drilling and production centers has been introduced [ref.1]. The island concept brings enormous flexibility in terms of managing future development uncertainties both subsurface and surface. The new subsurface development concepts include extensive utilization of ERD/MRC wells specifically designed and placed in conformance with geologically defined drainage areas. This strategy predicts significant improvement in plateau duration and sweep efficiency with fewer wells. The new islands based surface plan allows a phased installation of facilities, and space provisions to expand facilities to cater for subsurface uncertainties. It also handles the remnant life issues associated with the existing infrastructure (Wells, WHPT’s, pipelines and trunklines, satellites, central complex). This includes provisions for future requirements in terms of Water Injection, Artificial Lift and Gas Injection and other EOR applications.

This paper presents a success story covering the design, execution and post job evaluation of drilling and completing two Maximum Reservoir Contact (MRC) pilot wells. The wells were drilled and tested as part of a pilot wells programme aimed at proving-up to the well architectures planned to be introduced on a field wide basis. The carbonate field lies offshore Abu Dhabi in relatively shallow waters. Prior studies have confirmed the viability of continuing development of the field from artificial islands (drilling and production centers) by utilizing Extended Reach Drilling (ERD) and MRC well technology. The effectiveness of the MRC wells is critically dependent on well planning, design and placement in the reservoir interval. The paper describes the integrated workflow and well optimization process that have been applied to the two pilots which cover the following steps:Model developmentSimulation for completion options screeningProduction prediction by coupled reservoir-well dynamic simulationFlow assuranceAssessment of coiled tubing and wireline accessibilityDrilling and completions engineering analysis, time, cost and risk assessment. The application of this process has led to a number of (local) well records, firsts and learning’s that can be applied to future wells. The paper also summarizes the post drilling evaluation activities, which included running of production logging tools to optimize acid stimulation, an extensive flow test and data gathering program, and well model construction and validation to closely monitor and assess well performance.

SPE Members Abstract ODDA is an expert system designed to assist the drilling engineer, at the drilling site, in the engineering base or in the research center during the 4 functional phases of his work.Early planning phase, for designing the number and position of the different platforms or wellclusters. (Field planning expert system).During a well planning phase, for determining the optimum well trajectory in a single or multiwell environment. (Trajectory planning expert system).During the operational phase:3–1) for designing the bottom hole assembly suited to drill a given well section while minimizing the BHA make up time and implying no restriction on the drilling parameters to be applied.3–2) for deciding to pursue or interrupt the current bottom hole assembly run, ODDA will evaluate and extrapolate the assembly's trends, account for operational and geometrical constraints and eliminate unnecessary trips. (Drill Ahead/Pull Out Of Hole expert system).During the evaluation phase, for running queries and statistics, comparing actual and predicted behaviors and identifying trends in-the effects of different formations and drilling parameters on bottom hole assemblies (Post Analysis Module). The post analysis facility includes a survey validation process consisting in visually aided or fully automatic process consisting in visually aided or fully automatic filtration of survey errors. The drilling engineer can also design his own assemblies by accessing the mechanical analysis module. This module is an upgraded version of TOTAL's BHA2 program, which includes an enhanced graphical interface, program, which includes an enhanced graphical interface, a link with the system's central database and the possibility to run batch calculations while working with possibility to run batch calculations while working with other functionalities. The system's relational database allows the recording and processing of the well programs, the prognosed and processing of the well programs, the prognosed and actual geological data, the drilling parameters, the surveys and associated error parameters, the bits and bottom hole assemblies. Reports of predefined or customized format can be generated at any time. Its graphics capabilities and user environment, together with the above functionalities, make the ODDA system an integrated tool covering most aspects of directional drilling engineering. INTRODUCTION: The mechanical analysis of bottom hole assembly (BHA) behaviour by using computer models as well as the processing of directional data with relational databases is processing of directional data with relational databases is becoming an established part of directional drilling engineering. Most programs available today help the engineer to input drilling data for performance evaluation but do not provide BHA solutions for achieving a specified goal. Furthermore, drilling experience is not formalized for easy use in predictions for future wells. The experience and expertise is capitalized by the engineers who adjust intuitively their decisions according to the discrepancies observed between predictions and actual results and make their recommendations according to the context in which they operate. P. 167