Abstract
To meet the ever increasing global demand for energy, oil companies are under constant pressure to increase production. Today, operators have to drill deeper and further (extended reach, deviated, HPHT, etc.) to seek out new sources of supply. Such operations are known to regularly challenge operators with issues of high torque and drag, often leading to increased wear in rig equipment (e.g. drill strings, casings and mud pumps).
Lubricants have been known to be added to Water-Based Mud (WBM) to improve its lubricating properties. When the desired lubrication can no longer be attained by such means, operators switch to drilling with Non-Aqueous-Based Mud (NABM). The natural lubricating properties of the base oil used to formulate NABM help achieve a lower friction coefficient compared to drilling muds formulated with water. However, in view of the harsh drilling conditions mentioned above, there is a strong incentive to enhance the lubricating performance of NABMs even further.
The aim of this paper is to explain the challenges and share the results of developing a Non-Aqueous-Based Mud lubricant.
We will focus successively on:
- –
Screening tests on additives diluted in base oil from an adapted method using the High-Frequency Reciprocating Rig.
- –
The need to develop new tribological tools to assess the performance of an NABM lubricant
- –
Environmental constraints (biodegradability and ecotoxicity)
- –
Laboratory stress tests (thermal resistance, stability)
- –
Field test data on a deviated well in Nigeria, using 1% of lubricant in NABM, where a torque reduction of 20% was measured.
Conclusion: there is a clear operational benefit to the use of NABM lubricants, demonstrated both at laboratory level and in the field.
