Modelling and Verification of Gravel Pack Treatments in ACG Field to Improve Sand Control Reliability

Abstract

Proper design, installation and evaluation of sand control completions is vital for ensuring sand control integrity and mitigating against production deferrals due to sanding events. This is becoming increasingly important in the ACG Field, located offshore Azerbaijan, where wells require gravel pack completions with shunt tube technology and narrow operating windows between reservoir and fracture pressures. However, due to the lack of suitable commercially available software and a standardized workflow, gravel pack operations have been designed and evaluated using a combination of customized spreadsheets, historical data and software ported from other industry segments, none of which support the complex flow paths, conditions and range of technology utilized. While this did work, it was a time-consuming and inefficient process that required a number of assumptions and continuous data transfer which could allow for inconsistencies when applied at scale with an increasing number of users. To improve and standardize the design and evaluation of wells in the ACG field, a novel, commercially available sand control software was introduced for performing pre-job modelling, on-the-job calibration and post-job analysis in an integrated workflow for all stages of the sand control operation including wellbore displacements, step rate tests, gravel pack and reverse out. The software supports all common sand control technologies and flow paths, enabling the determination of optimal completion and hydraulic configurations during planning, identification of potential issues and redesign of the treatment during installation, as well as automatic analysis of surface and downhole data for a more detailed understanding of downhole events and mechanisms during post-job evaluation. This integrated workflow is presented using case studies from the ACG field to illustrate its application and benefits. The workflow is found to be simpler, more effective and more accurate than the techniques used in the past, enabling all necessary modeling to be quickly and easily performed in-house for improved planning and optimization of upcoming operations. Further, the automated analysis of surface and downhole gauge data enabled detailed evaluation to be completed in a timely manner which maximized the value of the acquired data and ensured lessons learned could be effectively implemented. Finally, the ability to directly compare simulated and actual treatment data allowed the engineers to calibrate and validate the model for more accurate modelling of future treatments.