Abstract Natural gas hydrates are crystalline solids made up of water and guest molecules. The most common hydrate formers are usually low-molecular-weight hydrocarbons typically found in natural gas. Salts, such as NaCl and CaBr2, can depress the water melting point temperature as well as hydrate formation conditions. Glycols, such as MEG, and alcohols, such as MeOH, have similar inhibitive effects to salts. Hydrate phase equilibria are of interest because hydrate solids in the pipes can jeopardize normal operation. However, the data for hydrate formation are limited under typical wellbore conditions, i.e., high pressure and high concentration of salts with organic inhibitors. Commonly used commercial software for hydrate phase equilibria shows unreliable predictions at these conditions. To improve the predictions, we have developed a simple but robust correlation, named Hu-Lee-Sum (HLS) correlation, to predict the hydrate suppression temperature with typical salts and organic inhibitors. To benchmark the predictions for hydrate dissociation, we herein report the experimental measurements for hydrate phase equilibria for brines and brine blends with MEG or MeOH, over a wide range of pressure. The measured data are compared to the predictions of three prediction tools (HLS correlation, PVTsim®, Multiflash®). For the systems and conditions tested, the HLS correlation shows robustness and accuracy, while PVTsim® and Multiflash® can be unreliable and in some cases give predictions with large deviations.

中文翻译：

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盐水混合物的气体水合物相平衡：测量和与预测模型的比较

摘要 天然气水合物是由水和客体分子组成的结晶固体。最常见的水合物形成剂通常是天然气中常见的低分子量碳氢化合物。盐类，例如 NaCl 和 CaBr2，可以降低水的熔点温度以及水合物形成条件。乙二醇（如 MEG）和醇（如 MeOH）与盐类具有相似的抑制作用。水合物相平衡很重要，因为管道中的水合物固体会危及正常运行。然而，水合物形成的数据在典型的井眼条件下是有限的，即高压和高浓度的有机抑制剂盐。用于水合物相平衡的常用商业软件在这些条件下显示出不可靠的预测。为了改进预测，我们开发了一种简单但稳健的相关性，称为 Hu-Lee-Sum (HLS) 相关性，以预测典型盐类和有机抑制剂的水合物抑制温度。为了对水合物分解的预测进行基准测试，我们在此报告了盐水和盐水与 MEG 或 MeOH 混合物在很宽的压力范围内的水合物相平衡的实验测量。将测量数据与三种预测工具（HLS 相关、PVTsim®、Multiflash®）的预测进行比较。对于测试的系统和条件，HLS 相关性显示出稳健性和准确性，而 PVTsim® 和 Multiflash® 可能不可靠，并且在某些情况下给出的预测偏差较大。为了对水合物分解的预测进行基准测试，我们在此报告了盐水和盐水与 MEG 或 MeOH 混合物在很宽的压力范围内的水合物相平衡的实验测量。将测量数据与三种预测工具（HLS 相关、PVTsim®、Multiflash®）的预测进行比较。对于测试的系统和条件，HLS 相关性显示出稳健性和准确性，而 PVTsim® 和 Multiflash® 可能不可靠，并且在某些情况下给出的预测偏差较大。为了对水合物分解的预测进行基准测试，我们在此报告了盐水和盐水与 MEG 或 MeOH 混合物在很宽的压力范围内的水合物相平衡的实验测量。将测量数据与三种预测工具（HLS 相关、PVTsim®、Multiflash®）的预测进行比较。对于测试的系统和条件，HLS 相关性显示出稳健性和准确性，而 PVTsim® 和 Multiflash® 可能不可靠，并且在某些情况下给出的预测偏差较大。