Tuesday April 2, 1:00pm

Mr Bill Fawcett

Petroleum Geologist
 

Drilling Fluids in the Petroleum Industry  
 

Abstract

Drilling fluids are an integral component to rotary drilling. The fluids have the task of cooling the bit, cleaning the drill hole, minimizing contamination of groundwater and stabilizing the wellbore. Control of downhole pressure is fundamental to safety of the rig and crew yet the brute force techniques of excessive overbalance are unacceptable to the contemporary reservoir engineering fraternity. To meet these challenges drilling fluids have advanced well beyond the simple 'mud' employed in the early 1900s and comprise a suite of leading edge polymers. The fluids now possess greater temperature stability for deep drilling and comprise corrosion and water loss inhibitors in addition to agents to improve rheology. Drilling muds can be tailored to suit drilling problems such as anhydrite or halite beds but always under the watchful eye of environmental regulators.

While invasion of the formation is largely undesirable the penetration of permeable zones by mud filtrate provides valuable information about potential reservoirs - log analysts make considerable use of invasion profiles for estimation of permeability. The negative side to invasion, however, is the risk of formation damage and the need to invoke correction charts as an indispensable tool when determining hydrocarbon saturation.

Despite advances in air drilling and underbalance technology the majority of wells in the world are drilled conventionally with mud and such fluids remain the cornerstone of effective drilling practice.

Biography of the Speaker

Bill Fawcett holds a BSc (Hons), 1975, and a Diploma of Education (1978), Univ. Adelaide. Bill has worked as a petroleum geologist for over 20 years. During that time he has been employed by Delhi Petroleum, Santos Ltd, Baroid NL, Oil Company of Australia and Origin Energy Resources Limited. His activities have embraced exploration and development drilling, regional and wellsite geology, log analysis, field mapping and hydrocarbon reserve estimation as well as maintenance of drilling fluids on rigs during employment with Baroid NL. These activities have, in one form or another, spanned South Australia, Queensland and Western Australia in addition to a period bobbing near the break of slope of the continental shelf, offshore Victoria. While openly admitting that some of the technology of drilling fluids has progressed beyond his term with Baroid he is keen to present the basics of what is a largely under-rated and poorly understood discipline yet one critical to effective field evaluation and both safety and successful petroleum drilling. Member of PESA, SPE.