Journal of Environmental Treatment Techniques  
2020, Volume 8, Issue 3, Pages: 1029-1035  
J. Environ. Treat. Tech.  
ISSN: 2309-1185  
Journal web link:  
Drilling Fluids: Presence of Hazardous BTEXs and  
Crystalline Silica  
Lakmun Chan , Nithiya Arumugam , Sathiabama T. Thirugnana and Shreeshivadasan  
Razak Faculty of Technology and Informatics, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100 Kuala Lumpur, Malaysia  
Department of Engineering, Razak Faculty of Technology and Informatics, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100 Kuala Lumpur,  
Ocean Thermal Energy Conversion (OTEC), Razak Faculty of Technology and Informatics, Universiti Teknologi Malaysia, Jalan Sultan Yahya Petra,  
4100 Kuala Lumpur, Malaysia  
Received: 25/03/2020  
Accepted: 26/06/2020  
Published: 20/09/2020  
In the oil and gas industry occupational health risks due to drilling fluids is severe. Mixing room, shale shaker room and drill floor are  
sites where workers are highly exposed to air pollutants, hazardous dust and even substances generated via drilling fluids associated activities.  
Barite, calcium carbonate and linear paraffin or olefin-based oil are three types of chemical that are greatly used in huge quantities to prepare  
drilling fluids. These drilling fluids contain hazardous substances and pose health risks. Due to the occupational health risk, Occupational  
Safety and Health Administration OSHA Europe and USA have issued guidelines for the permissible exposure limit (PEL) to be at 5 mg/m  
for barium sulphate, 10 mg/m for calcium carbonate, 0.05 mg/m for crystalline silica and 0.05 mg/m for oil mists. Therefore, this study  
identified the presence of benzene, toluene, ethylbenzene and xylene (BTEX) ionic mists and crystalline silica in the drilling fluids. The grain  
size distribution of additives used in the drilling fluids was also determined. The results showed the presence of BTEX and crystalline silica  
based on random sampling. Therefore, the existing control measures are necessary to reduce the occupational health risks. As a control  
measure, Artificial Intelligence (AI) and Internet of Things (IoT) are necessary to be introduced for the automation of drilling fluids associated  
Keywords: Drilling fluids; Occupation health risk; Hazardous; BTEX; Barium sulphate  
the drill hole via a mud pump and a discharge line. These drilling  
fluids are circulated down the drill string and then out through the  
bit. The drilling fluids are moved back up to the annulus and  
straight into the surface. The huge quantities of drill cuttings are  
composed of rocks and particulate mixtures which are released  
from geological formations generated during the drilling  
operation (5). Cuttings that are suspended from the hole by  
drilling fluids are unwanted and removed when they flow through  
the shale shaker (4). The above-mentioned drilling fluids flow  
cycle is illustrated in Figure 1.  
The selection of drilling fluids solely depends on their  
behaviours during the operation despite their drawbacks due to  
environmental concerns. The drilling fluids cycle will happen at  
elevated temperature together with agitation. This potentially  
exposes chemicals as well as oil vapour/mists; subsequently,  
affecting the health of workers both in short-term and long-term  
Drilling fluids have a vital role in measuring the success rate  
of drilling operations. These fluids are important to increase the  
oil recovery and shorten recovery time (1). Commonly used  
drilling fluids in the oil and gas industry are water-based, oil-  
based and synthetic-based muds (2). Drilling operation has three  
simultaneous systems that work in a boring hole. The first is a  
rotating system while second is a lifting system. The thirdsystem  
is a circulating system. The rotating system rotates the drill bit  
while the lifting system is used to lift up and lift down the drill  
string into the hole. The circulating system will circulate fluids  
around from the drill stem, out of the drill bit and up again into  
the hole at the surface.  
The drilling fluids are often used to eliminate cuttings from  
the drilling hole, transport them to the surface and are also used  
as a stabiliser and supporter to the wellbore (3). Besides, the  
drilling fluids help to cool and lubricate the drill bit (4).  
Preparation of drilling fluids starts at the mud mixing hopper. The  
mixing hopper performs as a chemical mixing station and then the  
fluids are retained in the mud pits/tanks before being pumped into  
(6). Comprehensive risk assessments of drilling fluid systems  
need to be conducted by the operator well planners, taking into  
consideration the aspects of health, environment and safety when  
deciding on the type of drilling fluids to be used for the system.  
Corresponding author: Nithiya Arumugam, Department of Engineering, Razak Faculty of Technology and Informatics, Universiti  
Teknologi Malaysia, Jalan Sultan Yahya Petra, 54100 Kuala Lumpur, Malaysia. E-mail: