琼东南深水钻井井筒天然气水合物抑制剂推荐浓度确定方法

中国石化将对琼东南深水区域展开油气勘探开发工作,而深水钻井时部分井筒处于高压低温环境中,若有气体侵入,易形成天然气水合物,导致诸多复杂情况的发生。通过对根据琼东南海水温度场的分布规律,考虑不同井段、不同钻井工况、不同钻井水力参数条件,分别建立琼东南深水钻井井筒内温度场和压力场的计算方法,并对深水钻井条件下天然气水合物相态平衡条件进行研究。建立了天然气水合物相平衡压力-温度条件的确定方法。结合深水钻井井筒中的温度场、压力场以及天然气水合物的相平衡条件,联合建立了琼东南深水钻井井筒中天然气水合物生成区域的预测方法和抑制剂浓度的确定方法,并通过琼东南华光区域某一口深水井进行实例计算,得出了各开次水合物可能形成的区域。并分析了钻井工程相关参数对水合物形成区域的影响规律。最终得出了抑制剂的推荐浓度方案。

Calculation Method of Gas Hydrate Formation Inhibitor Concentration for Qiong Dongnan Deepwatwer Drilling

Sinopec has planned to develop the oil and gas district of Qiong Dongnan deepwater area. Gas hydrate would be formed easily under high pressure-low temperature condition in some well section when gas kick happened and cause many problems during drilling. Temperature and pressure distribution and phase equilibrium condition determination method of Qiong Dongnan deepwater area have been established with consideration of Qiong Dongnan sea water temperature distribution and different well section, drilling condition and hydraulic parameters. The hydraulic formation region and inhibitor concentration prediction model are established based on the temperature-pressure distribution and hydrate phase equilibrium condition. According to the calculation example of a deepwater well in Huaguang district of Qiong Dongnan area, the law about influence parameters on hydrate formation region has been analyzed and recommended inhibitor concentration program is provided.