元坝气田硫溶解度Chrastil预测模型

Chrastil prediction model of sulfur solubility in Yuanba gas field

张睿 曾大乾 李童 李玉丹 史黎岩 张立举 王世红

中国石化石油勘探开发研究院，北京 102206 北京大学地球与空间科学学院，北京 100871 中国石化中原油田分公司勘探开发研究院，河南 濮阳 457001 中国石化中原油田分公司地面工程抢维修中心，河南 濮阳 457001 中国石化中原油田分公司技术监测中心，河南 濮阳 457001

Research Institute of Petroleum Exploration and Development, SINOPEC, Beijing 102206, China School of Earth and Space Sciences, Peking University, Beijing 100871, China Exploration and Development Research Institute, Zhongyuan Oilfield Company, SINOPEC, Puyang 457001, China Ground Emergency Repair Center, Zhongyuan Oilfield Company, SINOPEC, Puyang 457001, China Technical Monitoring Center, Zhongyuan Oilfield Company, SINOPEC, Puyang 457001, China

准确预测硫在含H2S气体中的溶解度是元坝气田硫沉积研究的关键之一。文中通过拟合元坝气田硫溶解度实验数据，得到适用于元坝气田的硫溶解度Chrastil预测模型，分析了拟合的双对数曲线特征；之后采用该模型分析了预测误差，并与目前广泛应用的Roberts模型预测结果进行了对比。研究结果表明：硫溶解度与气体密度双对数曲线呈分段式特征，因此需分段拟合；缔合数随温度压力变化而变化，反映溶质与溶剂分子在不同温度压力下的缔合作用，在储层温压条件下，平均每个硫分子结合2.58个混合气体分子；拟合得到的硫溶解度Chrastil预测模型预测结果较好，相对误差在2%以内，可以满足工程计算要求，而Roberts模型预测的硫溶解度比实验测量值高出2个数量级，应用该模型预测元坝气田硫溶解度，会高估元素硫的溶解量和析出量。文中的Chrastil预测模型能够准确预测元坝气田的硫溶解度，可为后续开展元坝气田考虑硫沉积的数值模拟研究提供理论基础。

Accurately predicting the elemental sulfur solubility in sour gas is one of the key issues to study sulfur deposition in Yuanba gas field. By fitting the experimental data on sulfur solubility in the Yuanba gas field, the Chrastil prediction model of sulfur deposition that is suitable for Yuanba gas field is obtained in this paper and the characteristics of the fitted log-log curves are analyzed. This model was used to analyze the prediction error, and the prediction results were compared with that of the Roberts model widely used at present. The research results show that the log-log curve of sulfur solubility and gas density presents segmented characteristics, so it needs to be fitted in segments. The association number varies with temperature and pressure, reflecting the association of solute and solvent molecules at different temperature and pressure. Under the conditions of reservoir temperature and pressure, each sulfur molecule will combine 2.58 mixed gas molecules on average. The fitted Chrastil model has good prediction results with a relative error of less than 2%, which meets the engineering calculation requirements. The sulfur solubility predicted by the Roberts model is two orders of magnitude higher than the experimental measurement value. The application of the Roberts model to predict the sulfur solubility in the Yuanba gas field will greatly overestimate the dissolved and precipitated amount of elemental sulfur. It is concluded that the Chrastil prediction model given in this paper can accurately predict the sulfur solubility in the Yuanba gas field, which can provide theoretical basis for subsequent numerical simulation studies considering sulfur deposition in the Yuanba gas field. 

10.6056/dkyqt202204002