Flow density across sand control screens in horizontal wells is very low. This is very favorable to the selection of screen-only completions as a cost effective sand control measure. However, phenomena specific to horizontal well completions have prevented them being as successful as they could be: 1) deployment contaminates the screen and reduces well productivity; 2) formation sands can mix in the annulus around the screen, modify the apparent sand sieve analyses, and affect the screen's ability to retain sand.

Therefore, screen sizing must not only include the selection of a screen medium capable to retain formation sands and tolerant to impairment caused by completion fluids, it also requires a careful review of other screen design features such as diameter, OD/ID ratio and the screen/blank ratio. To help select screens, sizing guidelines have been developed based on formation sand characteristics such as average size (D50) and uniformity (D40/D90).

A well productivity model has also been developed to assist in screen selection. Using reservoir characteristics such as permeability, heterogeneity, consolidation, design flowrate and fluid characteristics, it shows that incomplete screen clean-up can seriously affect well performance. While gravel packing reduces productivity losses associated with poor screen clean-up, minimizing screen impairment during deployment and/or cleaning it afterwards can prove to be a less costly alternative. A "Mud Plugging Index" is proposed to monitor screen plugging by a given drill-in fluid and help optimize fluid conditioning on the rig. Using centralizers on the screen during deployment and back-flowing fluid with a washcups assembly will also help enhancing well productivity.

You can access this article if you purchase or spend a download.