Ac. Seibi et al., Prediction of running forces in high curvature well bores using finite element analysis and artificial neural network, PET SCI TEC, 19(5-6), 2001, pp. 521-534
Estimation of the vertical force at the kick-off point (k.o.p) is of major
concern to field engineers involved in horizontal drilling. Prior knowledge
of the level of magnitude of the vertical force assists engineers in selec
ting appropriate hole paths to be drilled in order to minimize the risk of
pipe failure. Current methods employed to approximate the vertical force ar
e based on simple mathematical models that are not necessarily representati
ve of field conditions. This paper presents a new approach based on the use
of Artificial Neural Network (ANN) to predict the vertical forces at the k
.o.p, which is required to push pipes through curved hole sections. The art
ificial neural network learns the relationship between field variables and
the vertical forces through generated results using a finite element packag
e and offers a quick and efficient way of estimating vertical forces at the
k.o.p for various field conditions. The effect of pipe stiffness, hole rad
ius (build-up rate), hole roughness, and the horizontal drag force applied
at the end of build (e.o.b) are investigated. The finite element analysis a
nd ANN results showed that the running force variation at the k.o.p increas
es as the horizontal force, buildup rate and drag increase. The results als
o showed that the pipe stiffness has negligible effect on the variation of
running force at high buildup rate whereas a significant effect is observed
at low buildup rate.