The Maximum-Allowable Well Depth While Drilling of Extended-Reach Wells Targeting to Offshore Depleted Reservoirs

Xuyue Chen, Jin Yang, Deli Gao, Yongcun Feng, Yanjun Li and Ming Luo
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Xuyue Chen: MOE Key Laboratory of Petroleum Engineering, China University of Petroleum, Beijing 102249, China
Jin Yang: MOE Key Laboratory of Petroleum Engineering, China University of Petroleum, Beijing 102249, China
Deli Gao: MOE Key Laboratory of Petroleum Engineering, China University of Petroleum, Beijing 102249, China
Yongcun Feng: Department of Petroleum and Geosystems Engineering, The University of Texas at Austin, Austin, TX 78705, USA
Yanjun Li: Zhanjiang Branch of CNOOC Ltd., Zhanjiang 524057, China
Ming Luo: Zhanjiang Branch of CNOOC Ltd., Zhanjiang 524057, China

Energies, 2018, vol. 11, issue 5, 1-17

Abstract: In depleted offshore reservoirs, pore pressure declines and consequently horizontal in-situ stresses decrease as well. This causes a very limited well depth for extended-reach drilling targeting to offshore depleted reservoirs. In this paper, based on analyzing the safe mud weight window of the depleted offshore reservoirs, a model of predicting the Maximum Allowable Measured Depth (MAMD) for extended-reach drilling targeting to offshore depleted reservoirs is developed. Meanwhile, the numerical method of the model is proposed, and the key affecting factors of the MAMD are also investigated. The results show the pore pressure depletion has obvious effects on the MAMD. With the depletion of pore pressure, the safe mud weight window appears narrower and even disappears, consequently the predicted MAMD becomes shorter. For a normal regime depositional environment in the depleted reservoirs, it may be impossible to drill with conventional drilling method in the nearby directions of the maximum horizontal in-situ stress, while it may be much safer and attain a long MAMD when drilling in the directions near the minimum horizontal in-situ stress. Moreover, the MAMD will decrease with the increase of Poisson’s ratio and Biot’s parameter, and its response to Poisson’s ratio is more obvious. For a specific target depleted reservoir, the extended-reach drilling with a high borehole inclination may have a longer MAMD than that with a low borehole inclination. This paper presents a method for promoting the design of extended-reach drilling targeting to offshore depleted reservoirs.

Keywords: extended reach drilling; maximum allowable measured depth; safe mud weight window; depleted reservoirs; offshore drilling (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2018
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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