深水气井测试过程水合物形成预测

Hydrate formation prediction in deepwater gas well testing

李建周 高永海 郑清华 孙宝江 关利军

LI Jianzhou GAO Yonghai ZHENG Qinghua SUN Baojiang GUAN Lijun

中海石油中国有限公司深圳分公司，广东深圳　518067 中国石油大学石油工程学院，山东青岛　266580

CNOOC Ltd.-Shenzhen, Shenzhen 518067, China Petroleum Engineering College, CUPC East China, Qingdao 266580, China

深水气井测试过程中，水合物的形成会对测试作业造成很大影响，甚至导致整个测试作业的失败，进而引发重大事故。为保证深水气井测试的安全、顺利进行，有必要对测试期间水合物的形成规律进行分析，预测水合物可能形成的区域，加强水合物形成的预防工作。基于深水测试工况，针对开井流动与关井求压阶段，建立了温度压力的计算模型，并结合水合物生成条件，提出了深水气井测试不同施工阶段水合物生成区域的预测方法。对一口深水井的计算表明，开井流动期间，流量对水合物生成条件有很大影响，流量越低，水合物生成区域越大；关井阶段及初始流动阶段，管柱内压力较高，温度较低，形成水合物风险与区域较大，必须采取相应措施抑制其生成。

Hydrate formation is a big problem during deepwater gas well testing, and it would even lead to the failure of test opera-tion, and causes a major accident. In order to ensure the safety and success of deepwater gas well testing, it is necessary to analyze the formation law of hydrate during the testing and forecast region that hydrate may emerge to strengthen the hydrate prevention program. Based on the deepwater testing procedure, the calculation models of temperature and pressure have been established in conditions of flowing at open-up and requiring pressure at shut in, and then the prediction method of hydrate form region at different construction stage in testing is obtained combining with the formation condition of hydrate. A calculation result for a deepwater well shows that at the stage of flowing test, flow rate is an important factor of hydrate formation. The less output, the larger hydrate region. Another indication of the result is that high pressure and low temperature will cause serious hydrate problem at the stage of shut in and beginning of flow period. Measures must be taken to prevent the occurrence of hydrate in these periods.