Completion Technologies for HTHP Gas Fields in the Yinggehai Basin
(2.Zhanjiang Branch, CNOOC EnerTech Drilling & Production Co., Zhanjiang, Guangdong, China 524057)
【Abstract】The F Gas Field in Yinggehai Basin of the South China Sea is an HTHP gas field, and its characteristics of high temperature, high pressure and high CO2 content have been the challenge to the integrity of wellbore, so the completion method was selected pertinently according to the characteristics of reservoirs. Based on the principle of keeping both the safety and the economy, the tubing/casing was made by modified 13Cr material, and different types of production strings were designed. In terms of the characteristics of gas field and the development requirements, the selection of wellhead Christmas trees and downhole tools was carried out properly; the perforation pipe string was designed; and the proper annulus protection fluid was developed. In the end, a completion technology suitable for the development of HTHP offshore gas fields with high acidic gas content was formed. This completion technology has been applied in more than 10 wells of this gas field, and no sustained annulus pressure was observed during the production process, which indicated that the developed completion technology could effectively ensure the wellbore integrity of such gas fields and provide supports for the large-scale development of HTHP gas fields in the Yinggehai Basin.
【Keywords】 high temperature; high pressure; high CO2 content; completion; production string; corrosion prevention; Yinggehai Basin;
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