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Services for Science and Education – United Kingdom 664

European Journal of Applied Sciences (EJAS) Vol. 11, Issue 2, April-2023

industry primarily because of its consequences on the economic feasibility of the entire project.

The necessity to drill a functional hole with low cost and reduced environmental impact has

been a dream long held by drillers. The drilling mud generally referred to as “the blood of the

drilling process” determines whether the drilling operation is either materialized or not. This

is owing to the fact that the fluid plays a number of invaluable roles. Such as: cooling the drill

bit, cuttings removal, controlling pressure in the penetrated formation, deposition of thin, soft

and slippery filter cake on wall of the borehole, e.t.c.

The choice of the right drilling fluid and maintenance of the right properties greatly influence

the total well cost as rate of penetration, avoidance of delays resulting from stuck pipes, loss of

circulation, caving shales, etc., greatly affect the number rig days require to drill to total depth.

Since the 1990’s there has been a ban on the site discharge of drilled cuttings of Oil based muds.

This has led to the development of synthetic based drilling muds. These drilling muds provides

the same or even improved properties of oil-based muds coupled with the low toxicity of water- based muds, thereby allowing for discharge of drilled cuttings especially deep-water

exploration thereby reducing pollution hazard caused by diesel oil-based muds.

Petroleum-based oils used for drilling mud contains large amounts of aromatics and at least a

substantial concentration of n-olefins both of which may be harmful to plant and animal life, as

such, the petroleum drilling industry has overtime developed various oil-based muds which

reconcile performance and economic objectives with unique environmental and technical

obstacles or constraints. The harmful impact of diesel OBMs on the environment and most

importantly that of humans has led to several research for the past decades. This has to the use

of vegetable oils as substitutes for diesel in the formulation of OBMs.

These vegetable oils are extracted from edible and non-edible sources. The most common are;

Jatropha Oil, Sesame Oil, Palm Oil, Coconut Oil, Palm Kernel Oil, Rapeseed Oil, etc. In recent

times, synthetic oils are now considered to be more environmentally friendly than mineral oils

and diesel oil. Esters are formed by the reaction of a carboxylic acid with an alcohol under

acidic conditions (Norman 1997). The ingredients of esters used in SBFs include fatty acids

(carboxylic acids) with 8 to 24 carbons and alcohols with different chain lengths. 2-

Ethylhexanol (C8H18O, molecular weight 130.2) is the alcohol used most frequently; however,

mono- and poly-hydric alcohols (glycerols) may also be used. The fatty acids usually are derived

from natural vegetable or fish oils. They also can be made by oxidation of the terminal double

bond of LAOs Friedheim and Pantermuehl 1993).

SBF are more biodegradable and less toxic than most OBF, while retaining many of the technical

advantages of OBF (Neff et al., 2000). Because of their high cost, SBF usually are recycled rather

than disposed of in the environment or re-injected. However, some SBF reaches the ocean in

drill cuttings discharges, where these are permitted. Cleaned SBF cuttings usually contain

about 10 percent synthetic chemical (Annis, 1997; Neff et al., 2000). Cuttings cleaning

technology is being developed that can reduce the concentration of synthetic on cuttings to

below 5 percent. Cuttings containing less than about 5 percent synthetic do not clump when

discharged to the ocean; they disperse and settle over a wide area, preventing development of

a cuttings pile and speeding biodegradation (Getliff et al., 1997). A permit requires that

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Ehwarieme, F., & Akintola, S. A. (2023). Investigating the Effectiveness of Tiger-Nut Oil (Cyperus esculentus L.) as Base Fluid in Synthetic-Based Mud.

European Journal of Applied Sciences, Vol - 11(2). 663-675.

URL: http://dx.doi.org/10.14738/aivp.112.13044.

retention of synthetic base chemical on cuttings not exceed 6.9% for internal olefins or 9.4%

for esters (Rabke et al., 2003).

A good number of deep offshore exploration has taken place in Nigeria in which Synthetic Based

Muds (SBM) are been used. A good number of deep offshore exploration has taken place in

Nigeria in which Synthetic Based Fluids (SBF) are been used.

Okorie, et al. (2015), among other researchers carried out tests on Soya bean Oil as the external

phase of OBMs and the toxicity effect on beans plant. The formulated soybean mud properties

were compared with diesel oil mud properties. The compared properties were rheological

properties, yield point and gel strength, and mud density and filtration loss properties, fluid

loss and filter cake. The results obtained showed that soybean oil mud exhibited Bingham

plastic rheological model with low yield point and gel strength when compared with the diesel

oil OBM. Mueller et.al (1993), formulated and tested SBFs which were prepared from iso-butyl

oleic ester and iso-butyl rapeseed oil ester. Both esters showed a low kinematic viscosity but

their poor thermal stability resulted in undesirable high plastic viscosity after aging for 16h at

125°C. Canola oil also has been used in the formulation of SBMs. Ismail et al (2001), showed

that Palm oil-based esters have shown a potential of been used as drilling fluid. Studies have

showed that branched ester such as isopropyl laureate shows better fluid loss fluid loss

compared to linear esters such as methyl laureate. Dina kania et al (2018), evaluated the

performance of polyol esters as thinners and lubricity enhancers in invert emulsion SBMs, the

study showed that polyol esters enhanced the filtration properties of drilling mud. Dina kania

et al (2021), investigated the rheology of synthetic base mud containing non-ionic surfactant

pentaerythritol ester using full factorial design, the study showed that the plastic viscosity of

SBM increases with increasing non-ionic surfactant primary emulsifier ester concentration as

water-in-oil emulsion improves. The study also showed for that a better drilled cutting

transport, a high concentration of secondary emulsifier and a low concentration of primary

emulsifier should be used Findings have suggested that less brine in the formulation gave a

better performance of canola oil drilling fluid

From the work done so far, the contribution of vegetable oils has been significant plant oil

source as a substitute for diesel.

MATERIALS AND METHOD

Dry tiger nut seeds, grinding machine sodium hydroxide pellet beaker containing, Methanol.

Magnetic stirrer 5000ml graduated beaker, thermometer, clamp. Heating mantle, mixing bowl.

Mud Samples A, B, C represent SBMs oil-water ratio of 70:30, 75:25, 80:20 respectively, while

sample D represent diesel OBM with oil-water ratio of 75:25.

Extraction of Tiger Nut Oil

Dry tiger nut seeds were bought at Otovwodo market Ughelli, Delta State, Nigeria. The nuts

were sorted to remove all the dirt and bad nut. The sorted dried tiger nut was grounded using

a grinding machine, kept inside a sack before being placed under a mechanically pressurized

platform to remove the liquid. The extracted fluid was kept inside a bowl heated in a water bath

before been heated in a pot using firewood as the source of heat. The heating process was to

drive off water. Finally, it was filtered to remove dirt.