The New Biodegradable Surfactant Drilling Fluid for Offshore HPHT Drilling Environment

The global growing demand for energy has driven oil and gas industry towards drilling deeper wells, many which are subjected to high pressure and high temperature (HPHT) (Burdyn and Wiener, 1956; Larsen, 2007, Godwin et al., 2011). However, this development of deeper oil horizon is halted when conventional drilling fluids are unable to withstand these high temperatures (Burdyn and Wiener, 1956; Darley and Gray, 1988; Woha and Joel, 2011). Polymers (mud additives) degraded at elevated temperature and this causes unsatisfactory performances (Burdyn and Wiener, 1956; Darley and Gray, 1988).
The work was carried out to find the application of non-ionic surfactant used for Enhanced Oil Recovery (EOR)’s Polyethylene glycol (PEG) 550 based surfactant in drilling fluid. The focus will be put on the improvement of high pressure high temperature (HPHT) stability of conventional polymer, suspending agent (Xanthan Gum) and filtration reduction agent (PAC-LV) with the existence of surfactant.
The rheological and filtration properties of the drilling fluids were acquired using standard testing apparatus, viscometer and API filter press respectively. The performances were later evaluated with comparison with drilling fluids without surfactant.
It was observed that surfactant drilling fluids still exhibited slightly higher value in viscosity compared to base fluids after hot-rolling at elevated temperatures. Besides, it also showed a remarkable reduction in fluid loss by almost half even after undergone hot-rolling up to 125°C. These results showed that PEG550 had the potential to be used in offshore HPHT drilling environments.