浅层稠油化学降黏技术研究及应用

Research and application of chemical viscosity reduction technology for shallow heavy oil

针对浅层稠油油藏埋深浅、原油黏度高、热采动用效果差等开发难题,从稠油致黏机理、降黏机理、降黏剂靶向合成和性能评价等方面开展稠油化学降黏技术研究。通过分子动力学方法阐明了稠油中沥青质分子间π-π作用主导的致黏机理,其中,沥青质的面面堆积占主导作用。设计甲基丁香酚-丙烯酰胺-丙烯酸十八酯三元共聚物降黏剂分子结构,分子动力学结果显示,降黏剂可有效降低沥青质分子间π-π作用,降低稠油黏度。以甲基丁香酚、丙烯酰胺和丙烯酸十八酯为原料,优化合成降黏剂,该降黏剂在1000 mg/kg浓度下可实现净降黏率29.3%。在春风稠油油藏排601-20区块开展矿场试验,日产油量增加11.0 t,含水率下降6.0%,产出投入比为1.43∶1。试验效果验证了稠油降黏剂的可行性及有效性,可以为稠油化学降黏技术的发展提供理论指导。

In order to deal with shallow formation depth,high oil viscosity and low thermal efficiency for shallow heavy oil reservoirs,the viscous mechanism,viscosity-reduction mechanism,viscosity reducer synthesis and performance evaluation are investigated.The molecular dynamics are used to indicate the heavy oil viscous mechanism byπ-πstacking of asphaltene,in which,the surface stacking is dominant.The molecular structure of methyleugenol-acrylsmide-octadecyl acrylate is designed,and molecular dynamics shows that this viscosity reducer can effectively reduceπ-πstacking of asphaltene and reduce the heavy oil viscosity.The viscosity reducer is synthesized from methyleugenol,acrylsmide,and octadecyl acrylate.The net viscosity reduction rate can reach 29.3%at the mass fraction of 1000 mg/kg.The pilot test is conducted in Pai 601-20 block of Chunfeng oilfield.The daily oil production rate is raised by 11.0 t,the water cut is reduced by 6.0%and output-input ratio is 1.43∶1 after the viscosity reducer is applied.The pilot test proved the effectiveness and feasibility of the chemical viscosity reducer,which can provide theoretical guidance for chemical viscosity reduction technique.