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Issue:ISSN 1006-5539
          CN 51-1183/TE


Your Position :Home->Past Journals Catalog->2012 Vol.4

Application of Fuzzy-ball Drilling Fluids to Coalbed Methane Development in Yanping 1# Horizontal Well
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Key Words: Fuzzy-ball drilling fluid; Coalbed methane; Horizontal well; Application
Abstract: Yanping Well 1# is the first horizontal coalbed methane well located in the eastern platform area of Yanchuannan, Erdos Basin. The bed of interest is the 2# coal layer in Shanxi formation. Bentonite drilling fluid was used in the first spudding, with total depth of 140m and Φ244.5 mm casing down to a depth of 139 m. Polymer drilling fluid was used in the second spudding, with total depth of 1031m and Φ177.8 mm casing down to a depth of 1030 m. Fuzzy-ball drilling fluid was used in the third spudding so as to increase rate of penetration and stabilize the wellbore wall. Fuzzy-ball drilling fluid, used for coalbed methane, consists of such special disposal agents as nucleating agent, film-forming agent, capsule layer agent and fluffy agent, and potassium chloride added to it can improve inhibitive ability. The density of the drilling fluid was 1.05~1.11 g/cm3,with a shear stress of 2.5~8 Pa and a ratio of dynamic to plastic viscosity of 0.35~0.85 Pa/mPa·s. It took ten days to achieve the designed well depth of 1729.59 m. The finished drilling depth was 1732 m,with Φ114.3 mm sieve tube down to a depth of 1725.54 m. The average rate of penetration in the third spudding section was 5.09 m/h, not circular borehole wall was stable after soaked for 72 hours and signal transmission in the downhole was not affected and the third one was successfully docked with Yanping 1-V well in a single process. The well was reamed twice after well completion. The formation was held for 48 hours to make the gel breaker. Fresh water was used to replace the gel breaker and viscosity of the gel breaker was close to fresh water.
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