Impact of New and Ultra-High Density Kill Fluids on Challenging Well-Kill Operations

Abstract

Whilst significant efforts have been made worldwide on developing solutions for capping offshore blowouts, less has been done to ensure safe and reliable kill operations through a relief well. This paper presents new solutions to challenging kill operations.Well-kill operations through a relief well are still considered the most reliable and ultimate method for killing a blowing well. Strict legislation has been enforced for such operations, which challenges technical operational limits and margins. The requirement to be able to dynamically kill a blowing well through one single relief may restrict well design and thereby reduce contingencies.By pumping of ultra-high density kill fluid (UHDKF) or by injecting a slug of UHDKF as part of a staged well-kill operation, more reliable operations can be planned for with reduced pumping pressures, reduced horsepower requirements, significant fluid volume reductions and cost reductions. Furthermore, these ultra-high density fluids can enable kill operations that would otherwise require changes to the original well design.Some ultra-high density kill fluids have been formulated based on high density cesium brines. A clear brine with a density of 3.20 g/cm 3 and very low viscosity has been formulated by blending cesium phosphate and cesium tungstate brines. Higher densities can be achieved by adding a small amount of solid weighting material to cesium brines.The new ultra-high density kill fluids represent a great technological step. It is recommended that the findings presented in this paper are implemented in future Blowout Contingency Plans in order to ensure sufficient operational margins in the relief well planning and the kill programs.

Application of High-Density Brines in Drilling and Completion Fluids: Current Insights and Future Perspectives

“…Primarily, to preserve the wellbore stability and avoid the formation fluid influx, they enhance the hydrostatic pressure of the drilling fluid. , Furthermore, to maintain the borehole integrity and avoid the formation of cuttings, they support the carrying of cuttings out of the borehole. The success and safety of the drilling process are dependent on the capability of the HDBs to sustain the borehole integrity. , Finally, they assist in the cooling and lubrication of the drill bit prominently encompassing its lifespan . The application of HDBs in drastic drilling conditions is critical, such as oil drilling under high-temperature and high-pressure formations .…”

“…The success and safety of the drilling process are dependent on the capability of the HDBs to sustain the borehole integrity. 36,112 Finally, they assist in the cooling and lubrication of the drill bit prominently encompassing its lifespan. 41 The application of HDBs in drastic drilling conditions is critical, such as oil drilling under high-temperature and high-pressure formations.…”

Research of Bare-Free Drilling Fluids

“…Это все диктует необходимость бурения как можно большего количества скважин с одной точки, что предполагает большие горизонтальные отклонения скважин с использованием методов наклонно направленного бурения с целью эксплуатации трудно достигаемых залежей углеводородов или поиска подходящих мест для нагнетания воды. Данный раствор долгое время являлся основным решением для вскрытия и бурения в продуктивных пластах, благодаря вышеперечисленным свойствам и углеводородной основе, которая не конфликтует с пластовыми флюидами [24,25,27].…”