HYDROCARBON BASE FLUIDS FOR CHALLENGING DRILLING APPLICATIONS

摘要

A drilling fluid rheology and hydraulics modeling study was undertaken using three different hydrocarbon base fluids. Two different well configurations were modeled in the study, an extended-reach well, and a deep-water well. Results show that certain hydrocarbon base fluids consisting of normal, branched, and cyclic paraffins (mixed paraffins) can provide low equivalent circulating density (ECD), which is beneficial for drilling in narrow margin fracture gradient situations. Under these extreme conditions the low viscosity of the hydrocarbon base fluid is very important. In the comparison of different base oils Escaid~(TM) 110 having the lowest base oil viscosity leads also to the lowest ECD. Narrow margin fracture gradients are becoming more common with today's deep water and high angle, extended-reach drilling (ERD) applications. ECD management is critical for achieving an economical drilling operation in these cases, and may enable the drilling of an otherwise unreachable target resource.