摘要
综合考虑天然气水合物生成热力学、温度和压力条件,预测深水钻井井筒中天然气水合物生成区域。针对深水钻井的特点,建立了多相流控制方程组(包括各相的连续性方程和动量守恒方程)、环空和钻杆内的温度场方程以及水合物生成热力学方程。针对不同的钻井工况给出了方程的定解条件、方程离散方法以及求解步骤。通过仿真算例讨论了在钻进、停钻和压井过程中相关参数对天然气水合物生成区域的影响规律。结果表明:循环流量越高,抑制剂浓度越大,停钻时间越短,节流管线尺寸越大,水合物的生成区域就越小。算例研究还表明,多因素相结合抑制水合物生成的效果比单因素抑制水合物生成的效果更好。依据此计算方法还可对各参数进行优化。
It is essential to consider the thermodynamics, temperature and pressure conditions of gas hydrate formation, in order to predict the gas hydrate formation region in the wellbore of deepwater drilling. Multiphase flow governing equations （including continuity equation and momentum conservation equation）, temperature field equations in annulus and drill pipe, and hydrate formation thermodynamics equation are established, based on the characteristics of deepwater drilling. The definite conditions, discrete methods and iterative steps are given to solve the equations under different working conditions. Through examples of calculation, the impacts of relevant parameters on gas hydrate formation region during drilling, off drilling and well killing process are discussed. The result shows that the hydrate formation region is getting small when circulation volume becomes great, inhibitor concentration becomes high, downtime becomes short, or choke line size becomes large. And the result also indicates that it＇s more efficient to consider more factors to suppress hydrate formation. The parameters can be optimized based on the method.
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
2008年第6期731-735,共5页
Petroleum Exploration and Development
基金
国家"863"计划重大项目课题"深水钻完井关键技术"(2006AA09A106)
关键词
深水钻井
天然气水合物
多相流控制方程
温度场
热力学方程
deepwater drilling
natural gas hydrate
muhiphase flow governing equation
temperature field
thermodynamics equation
