Offshore rig, drilling well, Brazil 2013

Published: 18-07-2017| Version 2 | DOI: 10.17632/xn88z63ghs.2
Contributor:
Ricardo Antunes

Description

The subject of this data is the drilling process of an offshore well construction project in Brazilian pre-salt. It is constituted by a sample of continuous 395 meters drilling randomly selected from the project of an offshore oil well construction. The information containing the drill ahead goal and the current process duration was collected from operational reports and resampled to 181 samples representing the hourly process behavior when commanded by the input, establishing a system. Next, the estimation of a transfer function was used for the determination of a model that represents the dynamics of the system-based process. The estimation uses nine partitions of the dataset creating models based on different data sizes. The best model from each of the nine partitions presenting the lowest estimation unfitness value was selected and cross-validated by the remaining data. Later, the system response of the best model was analyzed. The case documentation provides details about inputs, outputs and brief explanations of the process parameters. Nonetheless, the documentation does not include any mathematical representation of the processes other than the drilling parameters and other activities performed while drilling, which constitute subsystems. For instance, the work instructions to drill a segment of 28 meters on the seabed: Drill ahead 8 1/2" hole from 3684 m to 3712 m with 480 GPM, 1850 psi, 15-25k WOB, 120 rpm, 15-20 kft.lbs torq. Perform surveys and downlinks as per directional driller instructions. Pump 15 bbl fine pill and 50 bbl hi-vis pill every two stand as per mud engineer instructions. WOB stands for weight on bit, an oil industry term for force caused by the weight of the mass of the collars that provide the downward force needed for the drilling bits to break rock.

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