Mitigating gas hydrate related drilling risks: A process-knowledge management approach

• Main Authors: Prassl, W.F., Peden, J.M., Wong, K.W.
• Format: Conference Object
• Language: English
• Published: Society of Petroleum Engineers Inc. 2004
• Subjects: Arctic
• Online Access: https://researchrepository.murdoch.edu.au/id/eprint/22764/

In order to secure future energy needs, exploration for hydrocarbon reservoirs occurs increasingly in Arctic and Deep Water Environments. These two drilling environments establish temperature-pressure conditions that are favorable to gas hydrates. Gas hydrates are crystalline complexes of water molecules, which trap gas molecules of suitable size inside their lattice structure. If they are created inside the well system, they may block the BOP or lines, which leads to well control risks. When gas hydrates exist naturally inside formations, drilling activities may lead to their dissociation, which can result in borehole stability problems, serious well gasification or subsequent well integrity problems on production. To mitigate these drilling risks a Process-Knowledge Management System (PKMS) has been developed. This PKMS allows the capture, verification, and intelligent use of explicit and tacit knowledge, and is constructed to allow exploitation of the knowledge from multiple field experts, company best practice policies, and latest technological findings. To incorporate and use the knowledge sources with embedded uncertainties, type-2 fuzzy set theory is applied. The PKMS is realized through individual reasoning blocks that set up a coherent reasoning lattice. The benefits of this approach are: An easy adaptation and upgrading of the system's knowledge, and Sensitivity for selection of particular reasoning blocks, depending on the current drilling scenario and conditions, is sustained. For the process of drilling within gas hydrate prone environments, the PKMS is actuated with multiple numerical simulations and gas hydrate related considerations. This paper discusses briefly the basic structure of the developed PKMS, as well as the numerical models used to describe the transient temperature field, the pressure profile and the gas hydrate kinetics applied.