УДК 622.243.134
“U-TUBE” EFFECT DURING DUAL GRADIENT DRILLING AND DRILLING UPPER INTERVALS OF OFFSHORE WELLS
Ganiev R.I. – Technical Consultant of Dual Gradient Systems LLC, radmirganiev@mail.ru
Luc DeBoer – CEO of Dual Gradient Systems LLC, Deboerlucas30@gmail.com
Agliullin A.H. – Doctor of Technical Sciences, Professor, Ufa State Petroleum Technological University, CEO of Center for Engineering Technologies LLC, dir@et.center dir@et.center
Ismakov R.A. – Doctor of Technical Sciences, Professor. Head of “Drilling oil and gas wells” Department, Ufa State Petroleum Technological University, ismakovrustem@gmail.com
Key words: u-tube, pilot hole, dual gradient drilling, flowstop, downhole valve, riserless drilling, offshore drilling.
The article describes problems associated with “U-tube” effect that occur when drilling pilot hole and upper intervals in offshore wells as well as during dual gradient drilling. Authors propose using a special bottom-hole valve “FlowStop” which allows controlling “U-tube” effect. Results of cost-benefits analysis, laboratory and field tests are presented that proving feasibility of using valve in offshore drilling.
