Standardization of Inactive Wells Audit Process for Well Abandonment andProduction Enhancement Candidate Screening

摘要

The reservoir management team is often facing a standardization challenge during audit and screening ofinactive wells, especially if this task involves multiple mature oil reservoirs or fields. Such a well candidatescreening process is normally required to select candidates for revival as well as plug and abandonment(P&A) candidates. Shut-in wells across different fields may be sharing common issues such as pressure depletion, liquidloading, and high water cut, however, the severity of well-related problems varies from one field to theother. This is in addition to the variation of wellbore mechanical issues such as well-bore integrity, wellboreaccessibility, and others. This paper aims to demonstrate a workflow to provide a quantitative ranking ofwells. It can be used to standardize an audit process during multi-reservoir or multi-field inactive-wellcandidate screening study. The standardization process was addressed by developing a tool that registers the shut-in well rankingupon completing the well potential and risk assessment process. Well level petroleum engineering andproduction data analysis such as decline curve analysis, nodal analysis and well modeling are performed toestimate the remaining well potential. Subsequently, to enable a comparison across different fields, behindpipe well potential was normalized using multi-field parameters. The audit process followed with wellworkover risking based on ease of workover intervention including workover options such as water shutoff, remedial wellbore integrity work, stimulation and others where it also draws on local knowledge forwell risk calculation. The approach presented in this study provides a comprehensive tool for both keyperformance indicators; remaining well potential and well risk, that are usually required to short-list wellsfor workovers. The standardized audit process was demonstrated in a case study where a large number of shut-in wellsfrom multiple mature oil fields were ranked. In this study, the 7 highest ranked wells were recognizedas production enhancement candidates and conversely, a number of wells with the lowest ranking wereidentified for well abandonment. Through this standardized workflow, the well risk assessment wasperformed efficiently with tools that enable a consistent result across different fields. It helped to acceleratethe reservoir management decision-making process in identifying wells with the most impact to increase the success probability during inactive well revival and workover. The workflow and the tool presented inthis paper has the potential to be used as analytic tool or template and can be used as a live document thatmay be adopted to reduce the workload and improve shut-in well management.