ABSTRACT
Drilling fluids has multiple functions during the drilling operations and these functions are carried out through the effectiveness of the properties of the drilling fluid (apparent viscosity, plastic viscosity, yield point, gel strength and Filtration loss). Gel strength plays a major role of solid particles suspension during tripping and string connection. Unfavorably low and high gel strength can possibly lead to clogging of the drill bit as a result of solids poor suspension, and increase in hydraulic horse power to effect proper rotation and difficulty in sorting out cuttings from the mud during treatment, analysis and recirculation in respective cases. Results from the tests gave reasonable viscosity value of 36cp at 600rpm dial reading. With this value, the lifting and suspending capacity of the mud is thus improved significantly. Combination of bentonite and Gum Arabic Powder also gave yield point of 24 1b/100ft2. Yield point is used to determine the chemical treatment needed to increase or decrease mud viscosity. Increase in yield point implies increase in viscosity (i.e. solid’s suspension ability improvement) and cleaning ability of mud, but excessive increase may cause flocculation. For moderately high viscosity yielding drilling mud, Combination of bentonite and Gum Arabic Powder gave a promising choice. Therefore, Gum Arabic Powder can be utilized in drilling mud for optimization of rheological properties in oil and gas industry.
CHAPTER ONE
1.1 INTRODUCTION
Drilling is an important aspect of oil and gas sector for without drilling, there is no access to the natural resources available below the earth crust. Drilling is a process of making a hole in the earths’ surface for the purpose of creating access to the desired resource below the earth crust.One of the important materials used in drilling is the drilling fluids commonly call drilling mud. Drilling fluids are heterogeneous mixture of chemical, water or oil andclay materials that help drilling operations.
Drilling fluids are primarily used for lifting cuttings to the surface, cooling the bit,lubricating the drill bit, increasing the stability of the boreholes, suspend cuttings in fluid if circulation is stopped, help in collection and interpretation of data available through drill cuttings, cores, and electrical logs; and provide frictionless environment between the drilling string and the sides of the hole. Ability to perform these functions depends on proper monitoring of its rheological parameters which are: apparent viscosity, plastic viscosity, gel strength and yield point. These properties are designed to suit specific operation depending on the aim of the drilling activity and the formation to be drilled.
The main factors governing the selection of drilling fluids are; the types of formation to be drilled; the range of temperatures; Strength, permeability and pore fluids pressure exhibited by the formation.
In drilling operation, clay is used as viscosifier which makes its effect in drilling operation a significant one. Clay used for drilling operation in Nigeria is imported into the country despite its abundance in the country. This has been a major challenge especially to the indigenous companies involved in the oil and gas because they have to import these materials at high costs and this has not allowed them to compete favorably with their foreign counterparts.
In the past, researches have been examining the possibilities of producing drilling fluids using strictly locally derived materials, this partly successful as it is discovered that Nigeria have the necessary materials to produce Locally based drilling fluids but the major problem encountered is that the gel strength of the drilling fluids produced using local substitutes is too low and the fluid loss is too high and as a result, this is not suitable for drilling processes (Bruton, J 2000).
In this paper, we attempt to use locally derived material for the production of drilling fluids that will be suitable in the Nigeria terrain and internationally for all purpose of drilling processes.
