Guidelines for Selection of Fluid Loss Control Methods Before and After Sand Control Treatments to Maximize Well Productivity and Cost-Effectiveness

Abstract

ABSTRACT The loss of completion and workover fluids into productive zones is a major concern particularly in high-permeability, unconsolidated sandstone formations where sand control is most typically required. Selection of the fluid density to balance the formation pressure is often based on an educated guess through previous experience in nearby or offset wells. Where overpressured formations are expected, balancing the formation pressure requires heavy brines, the loss of which into the formation can be quite costly when reservoir pressure is grossly overestimated. In underpressured formations, overbalance can be as high as several thousand psi even with very low-salinity brines, and maintaining a fluid level in the wellbore becomes extremely problematic. Long horizontal open holes present a formidable challenge for fluid loss control since cleanup of filter cake throughout the hole length using external breakers can be very difficult. In this paper, we review the currently available mechanical and chemical options for fluid loss control, and discuss the limitations of each method. Based on laboratory data and considering practicality in field applications, we offer guidelines for selection of fluid loss control method and/or material in order to maximize productivity. The guidelines are given for two general categories: Before Sand Control (e.g., after perforating with two-trip methods in cased-holes) and After Sand Control (either two-trip or single-trip). The mechanical options discussed include isolation and flapper valves, as well as a single-trip perforating and gravel packing method that eliminates the use of fluid loss control (FLC) pills and multi-functioning isolation systems. Chemical options include crosslinked HEC systems without particulates, and soluble particles in various carrier fluids. The particles may be soluble in water (sized salt), in acid (CaCO3), or in oil (oil-soluble resins).