BAKER HUGHES - Drilling Fluids Reference Manual

HYDRAULICS
HYDRAULICS
Chapter 9
A detailed understanding of the role drilling fluids hydraulics play in drilling operations is
required to adequately support drilling operations. Drilling fluids personnel must understand the
different concepts, models, and sets of equations which can be used to plan, optimize, and
calculate the hydraulics of a drilling operation. They must also be aware of the strengths and
limitations of the engineering software used for hydraulics simulations.
INTRODUCTION
Hydraulics calculations are recommended to be carried out using ADVANTAGE SM Engineering
Software. This is the most accurate tool available to Baker Hughes Drilling Fluids personnel for
performing hydraulics and hole cleaning simulations. The contents of this chapter are related to
ADVANTAGE SM Hydraulics and Hole Cleaning.
The calculation of the various hydraulic parameters of a drilling operation are very important in
order to control the many variables of the drilling fluid in such a manner that the well can be
completed safely, with minimum damage to the borehole formations, and at the lowest possible
cost. The optimization of any particular hydraulic parameter will primarily depend upon the
location of the drilling operation. For example, it is pointless to maximize bit hydraulic horsepower
or impact force when drilling in soft formations where the penetration rate is limited by the time
required to make a connection in the drillstring.
It is common practice to calculate a number of hydraulic parameters and include this information
on the fluid report. If any of these parameters are not optimal, alterations to fluid properties, pump
rate, or even bit nozzles may be made to compensate. This comprehensive approach is desirable
and is the main reason for developing computer programs such as ADVANTAGE SM Hydraulics
and Hole Cleaning. The following sections describe the hydraulic parameters and corresponding
equations used in a drilling operation.
RHEOLOGY
Rheology is the study of flow and deformation of matter, including liquids and solids. It is critical
to remember this definition and be aware that it is not possible to measure, increase, decrease, or
optimize rheology. Instead we can do this to viscosity or to rheological properties.
Rheological Terms
To better understand the impact of rheological properties, Figure 9-1 can be used to provide a
definition of some basic rheological terms. This illustration depicts the forces acting on a liquid
between two one square meter plates, which are separated by one meter. The bottom plate is
stationary and the top plate is moved at a rate of one meter per second. The amount of force
BAKER HUGHES DRILLING FLUIDS
REFERENCE MANUAL
REVISION 2006 9-1