Transient temperature and pressure calculation model of a wellbore for dual gradient drilling
During deep-water oil and gas explorations, the dual gradient drilling (DGD) technology provides solutions to problems caused by the narrow density window and the shallow gas by controlling the pressure profile in the wellbore. A transient temperature calculation model is established with consideration of the heat generated by the pump in the specific processes of the DGD systems. Besides, the momentum equation is modified by considering the lift force of the pump on the drilling mud in the pressure calculation. An iterative scheme for the coupled temperature and pressure calculations is developed. Besides, the transient temperature and pressure are analyzed for a deep-water well in South Sea. It is shown that the bottom-hole pressure varies significantly with the transient temperature in the wellbore, and the change of the bottom-hole pressure in the case of the DGD (626 kPa) is larger than that in case of the conventional drilling (115 kPa) due to the constant inlet pressure of the subsea pump. With this fact in mind, an adequate safety margin is strongly recommended to be considered during the hydraulic parameter design of the DGD. Our results further show that the DGD can significantly extend the operation range of the drilling fluid density, and the advantage becomes more obvious in a deep water.
Key wordsDual gradient drilling (DGD) transient temperature pressure
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- Chen G. M., Yin Z. M., Xu L. B. et al.. Review of deepwater dual gradient drilling technology [J]. Prtroleum exploration and development, 2007, 34(2): 246–251.Google Scholar
- Goldsmith R. Mudlift drilling system operations [C]. Offshors Technology Conference, Houston, Taxas, USA, 1998.Google Scholar
- Eggemeyer J. C., Conoco P. E., Akins M. E. et al. Subsea mudlift drilling: Design and implementation of a dual gradient drilling system [C]. SPE Annual Technical Conference and Exhibition, New Orleans, Louisiana, USA, 2001.Google Scholar
- Schumacher J. P., Dowell J. D., Ribbeck L. R. et al. Subsea mudlift drilling: Planning and preparation for the first subsea field test of a fullscale dual gradient drilling system at Green Canyon 136, Gulf of Mexico [C]. SPE Annual Technical Conference and Exhibition, New Orleans, Louisiana, USA, 2001.Google Scholar
- Gao Y. H. Study on multiphase flow in wellbore and well control in deep water drilling [D]. Doctoral Thesis, Qingdao, China: China University of Petroleum (East China), 2007(in Chinese).Google Scholar
- Bourgoyne A. T. J., Millheim K. K., Chenevert M. E. et al. Applied drilling engineering [M]. Richardson, Texas, USA: Society of Petroleum Engineering, 1986.Google Scholar
- Hoberock L. L., Thomas D. C., Nickens H. V. Here’s how compressibility and temperature affect bottom-hole mud pressure [J]. Oil and Gas Journal, 1982, 80(12): 159–164.Google Scholar
- Chen Z., Xie L. Special considerations for deepwater well temperature prediction [C]. SPE/IATMI Asia Pacific Oil and Gas Conference and Exhibition, Nusa Dua, Bali, Indonesia, 2015.Google Scholar