Ichthys Field Development - Implementation of a Multi-Disciplinary Well Optimisation Workflow for a Large Gas-Condensate Reservoir

摘要

Optimisation of development well locations is a critical field development objective to ensure maximi- sation of hydrocarbon production and gas plateau duration. In a large reservoir with relatively sparse well control, significant inter-well uncertainty can exist, resulting in a high degree of subjectivity in the selection of production well locations. Following the implementation of a comprehensive workflow to construct multiple geologic realisations of the Brewster reservoir, a two-step process was developed to: 1) objectively identify optimum production well locations that suited a selected range of geologic models, and 2) subjectively refine these locations to satisfy practical requirements. Optimum well locations were initially identified using a systematic approach covering a wide range of geologic scenarios based on an objective to maximise gas plateau duration. Resulting well locations for each realisation were then consolidated into a single well pattern using a frequency mapping technique. Subsequently, a subjective approach was adopted to refine these well locations based on considerations, including targeting of structurally high points, minimum inter-well spacing, step-out from subsea drill- centre locations, maximising the value of data acquisition (distance from existing well control) and reducing well construction complexity (minimising lateral step-out and drilling in non-preferred azimuth). Concurrently, optimisation of well geometry and total depth was investigated which indicated the potential for drilling/completion cost savings with negligible impact on predicted production performance. The integrated, multi-disciplinary nature of this methodology was paramount in effectively commu- nicating and satisfying well planning/execution objectives between key project disciplines.