含蜡油气水合物生成特性及其浆液黏度影响因素  

Formation characteristics of waxy oil and gas hydrate and factors affecting viscosity of the hydrate slurry

作　　者：张自印 庄乐泉 曹波波 罗泽利 敬加强[2,3] 孙杰 陈星宇[2] ZHANG Ziyin;ZHUANG Lequan;CAO Bobo;LUO Zeli;JING Jiaqiang;SUN Jie;CHEN Xingyu(CNOOC China Limited,Shenzhen Branch,Shenzhen,Guangdong 518000,China;School of Oil&Natural Gas Engineering,Southwest Petroleum University,Chengdu,Sichuan 610500,China;Oil&Gas Fire Protection Key Laboratory of Sichuan Province,Chengdu,Sichuan 610500,China)

机构地区：[1]中海石油(中国)有限公司深圳分公司,广东深圳518000 [2]西南石油大学石油与天然气工程学院,四川成都610500 [3]油气消防四川省重点实验室,四川成都610500

出　　处：《中国海上油气》2024年第3期221-229,共9页China Offshore Oil and Gas

基　　金：国家自然科学基金企业创新发展联合基金重点合作项目“深水蜡晶与水合物多相混输管道固相沉积与安全输运机制(编号:U19B2012)”;国家自然科学基金项目“管输热采稠油自生泡沫润滑稳定性及动力学行为研究(编号:52106208)”;四川省自然科学基金项目“热采稠油集输管道自生泡沫减阻机理研究(编号:2023NSFSC0924)”“深层低渗、稠油地面测试流程流动保障技术及工艺研究(编号:CCL2022SZPS0223)”部分研究成果。

摘　　要：蜡、水合物及其耦合沉积是海洋油气多相混输工艺潜在风险问题。以天然气、去离子水、3#工业白油和石蜡为实验介质,依托可视化高压反应釜,基于正交实验设计的方法,分别选用L9(34)和L16(45)正交表设计并开展了无蜡和含蜡2种体系下天然气水合物生成实验;以流体当量黏度为评价指标,分析了含蜡量、搅拌速率、流体平衡温度、含水率、起始压力对水合物浆液当量黏度的影响显著程度。实验结果表明:黏度值恒定并不能判断反应釜中水合物生成是否结束,因为在剪切稳定阶段,脱离搅拌中心区域的水合物与搅拌区域新生成的水合物存在一种“动态平衡”状态;含蜡量越高,水合物生长诱导期越长;在含蜡量2%与3%水合物的快速生长阶段,扭矩与转速会发生2次突变,第1次突变原因是蜡晶的大量析出导致搅拌中心区域油相胶凝结构增强,第2次突变原因是水合物大量生成并与析出的蜡晶相互吸附形成了蜡-水合物聚集体,在离心作用下脱离了搅拌中心区域;各因素对于无蜡和含蜡体系水合物浆液当量黏度的影响显著程度相似,搅拌速率均为主要影响因素。研究结果对深水油气管道的安全运行具有重要的理论意义和实用价值。Waxes,hydrates and their coupled deposition behave as potential risks in the offshore oil and gas multi-phase transport process.Using natural gas,deionized water,3#industrial white oil and paraffin as the experimental media,and relying on a high-pressure visible reactor,natural gas hydrate formation experiments were conducted in both wax-free and wax-containing systems based on an orthogonal design method,for which the L9(34)and L16(45)orthogonal table was selected.The effects of wax content,stirring rate,fluid equilibrium temperature,water content and initial pressure on equivalent viscosity of hydrate slurry were analyzed via taking fluid equivalent viscosity as the evaluation index.The experimental results show that the constant viscosity value is not sufficient to determine the completion of hydrate formation in the reactor.This is because in the shear stabilization stage,a state of"dynamic equilibrium"is existed between the hydrates leaving stirring central region and the newly generated hydrates in stirring region.Moreover,the higher the wax content,the longer the hydrate growth induction period.In the rapid growth stage of hydrates with wax content of 2%and 3%,the torque and rotational speed underwent two mutations.The first mutation was due to the precipitation of numerous wax crystals,leading to a stronger gel structure of the oil phase in the stirring central region.The second mutation occurred due to the separation of wax-hydrate aggregates from the central stirring central region under centrifugal forceof which the formation is achieved by generating and absorbing a large amount of hydrate onto precipitated wax crystals.The research results hold significant theoretical implications and practical value for the safe operation of deep-water oil and gas pipelines.

关 键 词：蜡-水合物聚集体 蜡晶 当量黏度 水合物 正交实验 影响因素 

分 类 号：TE866[石油与天然气工程—油气储运工程]