Title: A study of rapid increasing choke pressure method for sour gas kicks during managed pressure drilling

Authors: Miao He; Gonghui Liu; Jun Li; Mengbo Li; Gen Li

Addresses: China University of Petroleum, 18 Fuxue Road, Changping, Beijing, 102249, China ' China University of Petroleum, 18 Fuxue Road, Changping, Beijing, 102249, China ' China University of Petroleum, 18 Fuxue Road, Changping, Beijing, 102249, China ' CNOOC Research Institute, No. 6 Taiyanggong South Street, Chaoyang, Beijing, 100028, China; China University of Petroleum (Beijing), 18 Fuxue Road, Changping, Beijing, 102249, China ' China University of Petroleum, 18 Fuxue Road, Changping, Beijing, 102249, China

Abstract: The numerical simulation of rapid increasing choke pressure method for complete sour gas kick circulations is achieved, by using a transient, multiphase flow model, which has been verified with full-scale kick experimental date. The results indicate that the bottomhole pressure change rules can be classified into four cases based on the behaviour of the key parameter, which is choke pressure increment (ΔPc). Each case follows the identical four phases. Perfect well control procedure can be achieved by accurately adjusting ΔPc. A new method is proposed that could determine more precisely whether the formation flow ultimately stops by comparing the values between two points from bottomhole pressure or from standpipe pressure. The appropriate ΔPc interval can be also ascertained by combining with safe mud density window. The rapid increasing choke pressure method could effectively inhibits the dissolved H₂S from releasing and greatly reduce the gas expansion and resulting pressure fluctuation near the wellhead, thus it is quite suitable for sour gas development with low-high H₂S content. [Received: May 20, 2014; Accepted: December 13, 2014]

Keywords: numerical simulation; sour gas; kick circulations; multiphase flow modelling; choke pressure increment; bottomhole pressure; pressure drilling; well control; standpipe pressure; mud density window.

DOI: 10.1504/IJOGCT.2016.073783

International Journal of Oil, Gas and Coal Technology, 2016 Vol.11 No.1, pp.39 - 62

Received: 26 May 2014
Accepted: 13 Dec 2014
Published online: 22 Dec 2015 *

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