Enabling Drilling Operations Using Structured Data and Measured Response

Abstract

The scope of this paper is to show how digitized, structured data, as a combination of design data, operational data, riser analyses and measured riser response can be used to enable drilling operations on a subsea exploration with well challenging soil or/and harsh environmental conditions. The structural integrity of the well foundation and soil support has been verified by combining the structured data obtained from measurements with the design information. A sensor system has been fitted to the riser and BOP on mobile drilling units to monitor soil and structural integrity. The combination of pre-operational assessments and monitoring during operations has been carried out for 7 consecutive drilling campaigns, with two different semi-submersible drilling rigs. The work presented in this paper will give a comparison between the measured response and the up-front design analysis, and show show to combine the design information with operational data and measured response to enable future operations. During the design phase of a subsea exploration well a wide range of design assumptions must be considered. The range in high and low estimates for parameters such as soil support or riser and BOP mass and damping forces may be considerable. In general conservative parameters must be selected, leading to worst case scenarios, which again may lead to limited operational windows, introduce high cost mitigating actions or in worst case prevent operations from being carried out. This paper will present the benefit of using actual measured response and operational parameters back into the design loop when planning upcoming drilling campaigns. Structured operational data and measured response is used to improve analysis models; which lead to reduced conservatism. For cases of re-entry on an existing exploration well with heavier equipment, the measured soil support can be used to rule out some worst-case scenarios, and enable the upcoming operation. A case example of an exploration campaign enabled by the design loop will be shown.