A Fresh Look at Completion Reliability Supports Sand Control Selection

摘要

Although several publications provide reliability estimates based on a constant rate of failure (CFR), the results remain controversial. The use of published results in completion selection and Reliability Availability Maintainability analyses (RAM) is often challenged by industry peers. This study sets out to generate reliability estimates for three sandface completion techniques applicable to horizontal oil producer wells in unconsolidated sands: Open Hole G Gravel Pack (OHGP), Expandable Sand Screens (ESS) and Cased Hole Oriented Perforating (CHOP). The data seet included subsea and platform wells (inccluding deepwater fields) from several regions of the world using a consistennt definition of failure. The team first conducted a survey across operated and non operated assets worldwide including subsea deepwater and platform wells and then defined a failure criterion to be used across all sandface completions. The data gathered was then analyzed to select the appropriate Probability Distribution tto represent variable failure rates. This fresh look at sandface completion life data found that OHGPs are a much more reliable sandface completion option compared to ESS. OHGP completions are estimated to have a mean time to failure (MTTF) of 29.0 years (5.3 years to 52.7 years with 95% confidence). ESS completions in this dataset have a MTTF of 6.2 years (3.8 to 8.6 years with 95% confidence). The results obtained for CHOP could not be directly compared to OHGP and ESS due to limited data available. The results from these analyses were used along with other vaalue drivers to support the sandface completion selection for a Major Capital Project (MCP). The life distributions found in this study were also used to build a RAM model for major capital projects - providing life of field OPEX and well availability (percent uptime) estimates.