Optimization of chemical and mechanical disintegration process of drilling fluids.

Abstract

Drilling fluids are essential to conduct any drilling process. The amount of oil-based mud used daily is significant. Additives present in an oil-based mud ensure both unique properties and require proper waste treatment. Therefore this kind of drilling fluid is problematic in terms of handling and generates high treatment cost. This thesis provides a solution that changes large volumes of waste mud from enormous disposal expenses to a potential source of income. In order to analyse that issue, a wide description of oil-based mud was done and the method of destabilisation and three-phase separation was proposed, tested and validated on two types of oil-based muds (Carbosea OBM and SAR OBM). This step is crucial for reclaiming fraction of oil from source of waste, together with obtaining water phase and solid phase ready for purification. Chemical disintegration of oil-based slop mud by addition of five different MudSplit, followed by centrifugation was proved to give a positive results. Three-phase separation was obtained due to combination of optimal dosage, combined with proper retention time and centrifugal force, enhanced by an appropriate temperature. Results showed that MudSplit chemical is destabilising internal structure of emulsion by reducing the viscosity even in a small dosage. Temperature was found to be enhancing chemical destabilization, while retention time and high centrifugal force allowed quick and efficient separation of oil, water and solid phase. SAR OBSM gave three-phase separation despite the MudSplit type used in the lowest tested dosage 0,5 % [vol/vol%], retention time of 30 sec, 1500 RCF and 20 °C. For Carbosea OBSM the best results were recorded during using MudSplit001.