Oil based mud is widely used nowadays for drilling industry because it has good mud properties which waterbased mud cannot provide. However, it also has the drawback as well. Therefore, this article will recap both pros and cons of oil based mud in a simple way.
Advantages of Oil Based Mud
• The oil base mud is good for high temperature environment because the base fluid is oil.
• It is good for drilling into shale formation because it does not react with formation clay causing shale instability.
• It typically creates thin mud cake. This is really good because you can reduce risk for pipe stuck situation.
• It can be treated and reused. Using this mud for long run can reduce overall drilling mud cost.
• Oil base as external phase is good lubricant so it greatly reduce drilling torque.
• It is good to use in some areas where you face with hydrate problem such as deep water drilling.
• Typically, when drilling with oil base mud, gauge hole can be easily achieved.
Disadvantages of Oil Based Mud
Environmental concern – Oil base mud is considered as toxic waste therefore it cannot be disposed directly into land, river, or ocean. You really need to take special care when use it. Many governments do not allow oil companies which don’t have good waste management while drilling with oil base mud.
People Heath – This mud has hazardous vapors which will cause health problem to personnel who working with it in both short and long term. Moreover, personnel need to use proper PPE’s and protective crew in order to handle it because the oil base mud can irritate worker’s skin.
Cost – Mud cost of this system is higher than water base mud in terms of cost per barrel.
Gas kick detection – Gas kick is very difficult to identify because gas is soluble in oil. You may take kick but you will be able to see pit gain or flow increase at the first time. When the gas kick is moved upwards due to circulation, you will suddenly see pit gain, and flow increase because of gas expansion.
Cleanliness – It is pretty difficult to keep the rig clean while drilling with the oil base mud. Personnel need to take more time and effort to clean area where the oil base mud is on.
Equipment – Rubber parts is easily deteriorated by oil base. Therefore, personnel must be frequently check rubber parts exposed to this mud as rubber hoses, expansion joints, etc.
Reference Books: Drilling Fluids Book