International Congress on Engineering, Sciences and Innovative Technologies (ICESIT 2020) - Kuala Lumpur - Malaysia (2020-02-13)

Performance Appraisal of Flat Rheology Drilling Fluid System For Drilling Deep Water HPHT Reservoir
Drilling fluid perform many functions in a drilling process, including the removal of cuttings, lubricating and cooling the drill bits, providing the stability of the hole and preventing the inflow-outflow of fluids between the borehole and the formation. Both water and oil based drilling fluids are likely to experience a number of deteriorations such as gelation, degradation of weighting materials and breakdown of polymeric additives under HPHT conditions. A novel drilling fluid system is required in deep water drilling operations due to varying temperature profile from 4oC at the bottom of sea to as high as 205oC or even higher at the bottom of the hole in HPHT reservoir. Lower temperatures increase the rheology leading to higher Equivalent Circulating density (ECD) and at higher temperatures the rheology is lowered leading to hole cleaning issues. Flat rheology profile minimizes or eliminates such adverse effects on ECD, lost circulation, barite sag and hole cleaning activity. For instance, certain key rheological parameters, such as 6-rpm reading, yield point and gel strengths remain virtually unchanged when temperature and pressure are varied. This paper highlights the performance of various flat rheology drilling fluid systems and their rheology modifiers with special emphasis on water based mud system in deep water HPHT reservoir. Various rheological parameters are experimentally evaluated and the results indicate the constant rheological profile over wide range of temperature and pressures. On the basis of the study following drilling fluid system is recommendation: New Nano materials, KCl-Glycol, low-solids, non-dispersed (LSND) polymer systems (Poly Styrene-co-Butadiene), Glycol-polymer, and Mixture of barite and Manganese Tetra Oxide, TiO2 Nano fluids, polyol based drilling Fluid system in Water-Based drilling fluid system to provide a stable rheology and fluid loss for designing an HPHT tolerant Water-Based mud with an eco-friendly formulation. Key words: Deep water, High pressure High Temperature, Flat Rheology, Equivalent Circulating density (ECD), Lost Circulation, Barite sag.
Mr. Mamidi Lokesh Teja, Dr. D Linga Raju, Dr. PK Mahata