Drilling Technology for Deep and HPHT Containing Sour Gas well in the ChuanDongBei Field of China
Keywords:Drilling technology for deep and HPHT containing sour gas well, chuandongbei field of china, challenges and solutions, case study
ChuanDongBei Field of Sichuan Basin is a HPHT deep gas reservoir with multiple pressure systems, with maximum formation temperature up to 156Â and pressure gradient of 1.86 at the depth of 6500m. Part of the well section contains more than 5% CO2 and near to 10% H2S, so drilling operation is extremely challenged. Firstly, this paper introduces drilling challenges such as lost circulation, severe caving-in, pipe sticking in upper section, sour gas corrosion problems, low penetration rate in the middle and deep section.Secondly, a lot of available key drilling technologies are innovated and provided, including casing program optimization, air and nitrogen drilling to improve ROP, combination drilling with anti-HT motor and fit for purpose PDC bits, anti-HT mud along with losses prevention technologies such as MPD, anti-gas channeling and big temperature difference cementing slurry in the long interval, BOP and H2S sour gas monitoring system with emergency plan and some management advices for deep HTHP containing sour gas wells.Finally, some unexpectable application results regarding these techniques to solve a series of drilling difficulties have been mentioned according to 40 wells cases. Take well LG01-XY as an example, which was improved average ROP to 6.4m/h, extended the footage to 1713m in one specialized bit with air hammer, reduced drilling period to 145days, reached â€œzero pollution, zero harm, zero accidentâ€ achievement during H2S interval, got premium cementing result and well bore qualify. So it could be used as a technical reference while drilling in deep HTHP containing sour gas wells in similar geologically complicated gas fields.
Liu Shugen et al. Tectionics-controlled distribution of marine petroleum accumulation in the Sichuan Basin. China Earth Science Frontiers 2015; 22(3): P155.
Turki WH. Drilling and Completion of Khuff Gas Well, Saudi Arabia. SPE 13680; 1985: 33. http://dx.doi.org/10.2118/13680-ms
Chen Mingliang. Lessons Learned from Chemical Accident in China. Global Summit on Process Safety in TsingHua University 2014.
Deng Ke. Development Status and Application Prospect of Gas Drilling Technologies in China, Journal of Drilling and Production Technology 2015; 38(2): 20-21.
Wang Yanmin. Study On Dry Well Cementing Technology Used In Tarim Oilfield Large Size Deep Well, Journal of Drilling and Production Technology 2015; 38(1): 22-24.
Huang Hong-chun and Zheng Xin-quan. Cement systems for well cementation in gas fields with highpressure high gas production rate and high sulfur concent. Journal of China University of Petroleum 2011; 35(1): 78-79.
Li Rong, et al. Key Technologies for Deep and Deep Wells in HTHP and Sour Gas Fields in China, SPE 177515, 2015.
Yongsheng Ma, et al. Petroleum geology of the Puguang sour gas field in the Sichuan Basin, SW China. Marine and Petroleum Geology 2008; 25: 357-370. http://dx.doi.org/10.1016/j.marpetgeo.2008.01.010