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CHAPTER ONE

Equipment in Mud Circulating
Systems

Contents
1.1 Introduction 3
1.2 Mud Pumps 3
1.3 Drill Strings 6
1.4 Contaminant-Removal Equipment 11
Summary 18

1.1 INTRODUCTION
Figure 1.1 shows a typical mud circulating system (Lyons et al.,
2009). The drilling mud travels (1) from the steel tanks to the mud
pump; (2) from the pump through the standpipe and the kelly to the
drill string, which consists of drill pipes and the bottomhole assembly
(BHA), with a major length of drill collars; (3) through the drill string to
the bit; (4) through the nozzles of the bit and up the annular space
between the drill string and the borehole (open hole and cased hole sec-
tions) to the surface; and (5) through the contaminant-removal equip-
ment back to the suction tank. The contaminant-removal equipment can
include shale shakers, degassers, hydrocyclones (desanders and desilters),
and centrifuges. An integrated unit of desanders and desilters is called a
mud cleaner. This chapter provides a brief introduction to the equipment
that controls the circulating pressure of the system.

1.2 MUD PUMPS

Mud pumps serve as the heart of the mud circulating system.
Reciprocating piston pumps (also called slush pumps or power pumps) are
widely used for drilling oil and gas wells. The advantages of the reciprocat-
ing positive-displacement pump include the ability to move high-solids-
content fluids laden with abrasives, the ability to pump large particles, ease

Applied Drilling Circulation Systems. DOI: 10.1016/B978-0-12-381957-4.00001-2
© 2011 Elsevier Inc. All rights reserved. 3