S. Miska et al., TYPE CURVES FOR PREDICTING DIRECTIONAL TENDENCIES OF SIMPLE BOTTOM-HOLE ASSEMBLIES, Journal of energy resources technology, 120(3), 1998, pp. 193-200
The paper provides solutions for predicting directional tendencies of
slick and single stabilizer bottom-hole assemblies (BHA) in curved bor
eholes. Solutions are derived in a curvilinear system of coordinates i
n a dimensionless form. These solutions are presented in the form of t
ype curves. Type curves allow for quick evaluation of directional tend
encies of a given BHA by providing values of side force and tilt angle
at the bit. Using these values an anticipated direction of bit displa
cement is evaluated, using concepts of formation anisotropy index (FAI
) and bit anisotropy index (BAI). Procedures are illustrated by exampl
es of evaluation of side force and tilt at the bit for a slick and sin
gle stabilizer BHA. The resulting bit displacements are calculated ass
uming formation anisotropy and drill bit directional tendencies (FAI a
nd BAI). The results derived from type curves are in agreement with co
mputer simulated data. The comparison shows that application of graphi
cal solutions (type curves) yields only slight error that can be ignor
ed for practical purposes.