Abstract

This paper presented the extended reach well construction results to date of 3 infill wells: YA-01, YA- 05ST1, and YA-12ST1 during the Phase VI development drilling campaign in Yetagun gas field, offshore Myanmar which had delivered top-quartile drilling performance throughout every phase of well delivery.

The significant changes in drilling practices had led to the overall time and cost savings. Systematic approach to benchmarking drilling performance had been incorporated into the efficiency of the operation based on the Key Performance Indicators. Every phase of drilling, evaluating, and completing high angle wells was analyzed. The main technical hurdles contributed to the success of these wells were drilling practices, mud selection and directional control technique. Section-by-section was being described in the paper taking into account the factors that contributed to a top-quartile drilling performance including wellpath design, hydraulic, bottom-hole assembly design, drillstring design and torque and drag reduction methods. A few offset wells were selected and analyzed in order to act as a benchmark of expected performance, but up-front effort was established by proposing the significant key performance indicators (KPIs) which required specialized resources.

Value was generated through performance improvement. Engineering team of the drilling campaign dramatically achieved all the KPIs in the top quartile with zero LTI and successfully secured the reservoir target with the maximum drainage contacts as well as meet the gas volume target. Every aspects of the well design and construction was discussed, challenged and where possible, optimized for further study. The dramatic outcome of the drilling performance always came from the combination of some small incremental improvements and step-change innovations. Statistically analyzing of the KPIs covering the central tendencies and convergence link to the consideration of benchmarks. YA- 05ST1 successfully achieved Best in Class for WCPF and DCPF whereas the DDPTF of all the 3 wells were categorized in Quartile 1 performance. Among the significant changes in drilling practices that contributed to the time saving were the waiving of pilot hole, utilization of casing drive system, installation of tubing isolation Valve-Flapper for completion and implementation of drill to limit approach. Moreover, both the techniques and lesson learnt throughout the campaign were continuously revised, improved and distributed with the aim that the information can be built upon and lead to further improvements in the next extended reach well delivery.

In conclusion, the key differences in drilling practices throughout the campaign were proven to be practicable and in fact play an important role in time saving. Since the ERD has become an ever-more important enabling technique to exploit hydrocarbons nowadays, the replication of the best practices and lesson learnt should be shared for future extensive ERD wells planning and executions.

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