To all CFD experts

Can we model drillng operations using CFD (i.e. can soil be assumed to behave as fluid?)

thanks.

raj

(1). No. It is normally considered as solid.

..or a porous media..

as the guys said it isn't fluid. but you can take something from fluid dynamics to help you. normally in solid mechanics the structure (solid) is viewed in the lagrangian frame of reference (the solid is the domain) in fluid mechancs the eulerin frame is mostly used (the fluid passes through the domain) except sometimes for free surface flows. i've seen examples where the solid has been treated with the eulerian frame of reference. the case was a wire drawing process where the wire is being pulled through a rigid die. instead of folowing the wire as the die moves over it the process watches the die as the wire moves through it. the problem is then onverted form a transient (nonlinear) problem to a steady state problem. it was very cool. the presentation was made by a professor in mech eng at the Univ. of Illinois Urbana Champaign if you want to check it out. the problem seems conceptually similar to yours. different materials though

Thank you Dr Bradford. I'll contact the Prof. you mentioned. Do you have any other detail of him? raj

It depends what you label CFD.

A few years ago, one of my students was involved in simulating the flow around a drill head used for oil/gas exploration. The geometry was pretty horrible but the objective was to establish if the approach was viable with a view to optimising the design to help keep the teeth clear (fluid was pumped via various jets to the head). In comparison with some flow visualization things seemed to be reasonable.

Using alternative stress-deformation/rate of deformation relationships and perfoming fluid-structure predictions is straightforward in a research environment. I am not sure about commercial packages but would assume you could do something.

please don't try to flatter me i'm only a master's student. i'm glad it seems i come off like a PhD though ;-) all i can remember about this gentleman was that he was in the mechanical engineering departmant, he was tall, white, and his reseach areas were structures and optimization. if i find out i'll let you know. remember to get back in contact with me.

I'm just writing a Master's Thesis "Hydraulic Optimization of Dual-Body Slimhole Bits by Use of CFD" and I simulated some slimhole PDC bits. The only problem was the geometry, but with a little bit of patience this can be solved. If you have access to SPE (Society of Petroleum Engineers, www.spe.org) papers you should check the following: SPE/IADC 37580: "Using New CFD Techniques to Improve PDC Bit Performance" SPE 48937: "Effect of Completion Geometry and Phasing on Single-Phase Liquid Flow Behavior in Horizontal Wells" SPE 54595: "Optimization of Slimhole Dual-Body Bits by Experiment and CFD" SPE 20928: "Hydraulic Optimization of PDC Bits" SPE 28315: "A Methodology Using Laboratory Experiments and Numerical Modeling To Optimize Roller Cone Bits Hydraulics"

Anyway, there are a lot more papers published on the use of CFD in petroleum engineering, this only to name a few. If you have no access to SPE papers, contact me per email, maybe we can arrange, that I send you one or another as pdf.

I hope, this is a help for you.