Production and drawdown data from 10 subsea deepwater fractured wells have been modeled with an analytical model for unsteady-state flow with fines migration. The simulation results and the field data indicated a good match, within 5%. This paper describes the methodology used to integrate the modeling predictions with field and laboratory data to identify probable causes for increasing skins and declining productivity-index (PI) values.
Introduction
Fines migration is a complex phenomenon that can challenge the economic viability of a project because of well-productivity decline, lower-than-expected hydrocarbon recoveries per well, large capital expenditures to drill and complete additional wells, and high operating costs from suboptimal facility designs. Excessive fines production may also result in equipment erosion and corrosion, formation of hard-to-break emulsions, and plugging of flowlines and surface facilities, all leading to potential hazardous situations.
This paper describes a multidisciplinary approach in which fines-migration modeling has been integrated with field and laboratory data to ascertain whether fines migration may be associated with rapidly increasing skins and declining PI values observed in a subset of deepwater fractured wells. Laboratory studies exhibit fines release and migration during coreflooding and stress testing; the field well-productivity data are well-matched with the mathematical modeling.
Fines-Migration Modeling
The traditional mathematical model for fines migration assumes release intensity to be proportional to differences between the current and critical values of velocity, salinity, pH, and stress.
