THE USE OF COCONUT FIBRE AS STANDARD pH ENHANCER FOR DRILLING MUD FORMULATION
CHAPTER ONE
BACKGROUND OF STUDY
1.0 Introduction
A
drilling
fluid, or mud is any fluid that is used in a drilling
operation in which that fluid is circulated or pumped from the surface, down
the drill string, through the bit, and back to the surface via the annulus.(Growcock
et al., 2005).The successful and cost of a drilling
process is known to depend extensively on the asset of the drilling
fluid used (Gray et al., 1980). Drilling
mud circulates in a loop, from the platform, where it is forced down into
the formation by entering the drill string, and pushed up to the surface again
via the drill bit. The fluid characteristics such as density and temperature
are variables that need to be regularly monitored for perfect drilling
conditions of the well (Issham et al. 1985). They provide primary well control
of subsurface pressures by a combination of density and any additional pressure
acting on the fluid column (annular or surface imposed). They are most often
circulated down the drill string, out the bit and back up the annulus to the surface
so that drill cuttings are removed from the wellbore. Drilling
fluids have a number of alternative names, acronyms and slang terms used
within the industry. The most widely used name is “mud” or “drilling
mud” and both these terms will be used interchangeably throughout this
chapter. Other drilling
fluid names and acronyms are: water-based mud (WBM), oil-based mud (OBM),
synthetic-based mud (SBM), non-aqueous fluid (NAF), invert emulsion fluid
(IEF), high performance water-based mud (HPWBM), drill-in fluid (DIF) and
reservoir drilling
fluid (RDF). Similar to drilling
fluids are so-called completion fluids that are used to finish the well
after drilling
is completed. The fluids used during completions are often referred to as work
over and completion (WOC) fluids, clear brines and/or packer fluids. Drilling
fluid is a major factor in the success of the drilling
program and deserves careful study.

Figure
1.0: Drilling
fluids stored in the mud tank under agitation.
The
performance of the drilling
fluid is critical to everyone involved with the operation and to all
aspects of the drilling operation. The drilling
fluid is the primary means to keep the well from blowing out and it is
responsible for keeping the hole in good condition such that drilling
operations can continue to the desired depth. Drilling
and completion fluids are one of the most important parts of the well
construction process and ultimately the performance of the fluid will determine
the success or failure of the operation. The responsibility of the proper
selection and application of fluid is held jointly between the fluids supplier,
the drilling contractor and the operator.
The
research work focused on the use of Nigeria local materials in enhancing the drilling
mud pH, its performance and contribution as drilling
fluid properties and ensuring quality in hole making. Drilling
fluid pH measurements and pH adjustments are fundamental to drilling
fluid control because clay interactions, solubility of additives, and
contaminant removal are all pH-dependent.
PH
is a value representing the hydrogen ion concentration in liquid and it is used
to indicate acidity or alkalinity of drilling
mud. The pH is presented in a numerical value (0 – 14), which means an inverse
measurement of hydrogen concentration in the fluid.
The
pH formula is listed below;
pH = - log 10
[H]
Where: H is the
hydrogen ion concentration in mol.
According
to the pH formula, the more hydrogen atoms present, the more acidity of
substance is but the pH value decreases. Generally speaking, a pH of 7 means
neutral. Fluids with a pH above 7 are considered as being alkaline. On the
other hand, the fluids with pH below 7 are defined as being acidic.
In
the drilling
mud, there are three main chemical components involved in Alkalinity of drilling
fluid, which are bicarbonate ions (HCO3--), hydroxyl
ions (OH --), and carbonate ions (CO3-2). The
Alkalinity means ions that will reduce the acidity.
In
order to get accurate measurements for the pH, using a pH meter instead of
using a pH a paper is recommended because it will give more accurate pH
figures. Additionally, pH meters must be calibrated frequently.
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USE OF COCONUT FIBRE AS STANDARD pH ENHANCER FOR DRILLING MUD FORMULATION
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