engleski

Rheology Comparison of Different Drill-In Fluids

The use of horizontal wells to obtain more cost-effective production from mature and new developed reservoirs has become very popular. Since these wells often employ open hole completions, success depends on the fluid system used during drilling and completion. Drill-in fluids are formulated to provide lubricity, inhibition, borehole stability, optimum solids suspension and hole cleaning under laminar flow conditions and at low shear rates, as well as excellent particle suspension under static conditions. They also protect pay zones by forming an efficient filter cake to control fluid loss, stay intact during completion operations and clean up easily. Some of drill-in fluids use low shear-rate viscosity (LSRV) to minimize fluid invasion into the formation. Low shear-rate viscosity is also critical to provide optimum hole cleaning, assists with well bore stability, minimize exposure time and reduce pump pressure. A lab study of three drill-in fluid systems has been performed to determine rheological properties (Plastic viscosity, Effective viscosity, Low-shear viscosity, Low-shear-Rate Viscosity-LSRV, Yield point, Gel strengths) with different concentration of selected viscosifier (biopolymer) using Fann and Brookfield DV-II+ viscometers. Comparison of collected data by these viscometers is presented too.

drill-in fluids; rheologigical properties; LSRV value

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