Gas Hydrates and Offshore Drilling: Predicting the Hydrate Free Zone
Gas Hydrates and Offshore Drilling: Predicting the Hydrate Free Zone
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DOI：
10.1111/j.1749-6632.2000.tb06795.x
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发表时间：
2000-01
影响因子：
5.2
通讯作者：
K. Østergaard;B. Tohidi;A. Danesh;A. Todd
中科院分区：
文献类型：
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作者：
K. Østergaard;B. Tohidi;A. Danesh;A. Todd
摘要：海上钻井中一个众所周知的危险是，如果碳氢化合物从储层流入井眼（例如井涌），就会形成天然气水合物。这可能会堵塞防喷器组、压井线和扼流圈，阻碍钻柱的移动，并导致严重的操作和安全问题。目前，钻井液中添加盐以抑制海上和北极钻井中水合物的形成。对于深水钻井，即使是饱和盐溶液也可能无法提供所需的保护，除非与化学抑制剂结合使用。报道的关于钻井液中天然气水合物形成的实验数据非常有限，并且在某些情况下不一致。可用的预测方法通常是基于有限数据且应用有限的经验相关性。在本演讲中，提出了一种能够预测盐（NaCl、KCl、CaCl2、NaBr、甲酸钠等）和化学抑制剂（甲醇、乙醇、乙二醇、甘油等）存在下的无水合物区的热力学模型。开发的模型已用于预测为海上和深水应用设计的钻井液中的无水合物区。将预测结果与实验数据和经验相关性进行比较，证明了热力学模型的可靠性。
Abstract: A well‐recognized hazard in offshore drilling is the formation of gas hydrates in the event of a hydrocarbon flow into the well bore from the reservoir (e.g., a kick). This could potentially block the BOP stack, kill lines and chokes, obstruct the movement of the drill string, and cause serious operational and safety concerns. Currently, salts are added to the drilling fluids to inhibit hydrate formation in offshore and arctic drilling. For deep water drilling, even saturated saline solutions may not provide the required protection, unless combined with chemical inhibitors. The reported experimental data on gas hydrate formation in drilling fluids are very limited and in some cases inconsistent. The available predictive methods are generally empirical correlations based on limited data and with limited application. In this presentation, a thermodynamic model capable of predicting the hydrate free zone in the presence of salts (NaCl, KCl, CaCl2, NaBr, Na‐formate, etc.) and chemical inhibitors (methanol, ethanol, ethylene glycol, glycerol, etc.) is presented. The model developed has been employed to predict the hydrate free zone in drilling fluids designed for offshore and deep water applications. The predictions are compared with experimental data and an empirical correlation, demonstrating the reliability of the thermodynamic model.