稠油热采时移地震监测正演模拟分析

Forward modeling of time-lapse seismic monitoring for thermal recovery in heavy oil reservoirs

(1.大庆石油学院地球科学学院，黑龙江大庆163318；2.河南理工大学，河南焦作454000；3.中国石油化工集团公司胜利油田地球物理勘探开发公司,山东东营257100)

Geosciences College, Daqing Petroleum Institute, Daqing 163318, China

我国具有丰富的稠油资源，但国内外针对陆相薄互层稠油油藏的热采动态时移地震监测研究还很少。在认真分析热采对储层弹性特性影响的基础上，结合油藏开发理论和岩石物理测量结果，建立了薄互层油藏火烧油层动态模型，开展了时移地震正演模拟研究，结果表明：稠油热采(注蒸汽、火烧油层、注热水)会引起储层岩石和孔隙流体弹性特性的显著改变，从而导致明显的地震振幅差异。利用时移地震振幅差异可以区分油层中的高温区范围，跟踪高温前缘，甚至确定其推进速度。但因单层厚度小、地震分辨率低，横向上难以精细划分出油藏工程中所确定的不同区带，纵向上难以确定储层内热采前缘分布的非均匀性。

There is abundant heavy oil resource in China, but few researches on time-lapse seismic monitoring focus on the thermal recovery of heavy oil in a thin inter-bed reservoir at home and abroad. Aiming at this problem, we analyzed the effect of thermal recovery on heavy oil elastic behaviors, established a thin inter-bed fire flood dynamic model, and performed the forward modeling of time-lapse based on reservoir development theories and petrophysical measurements. Results show that thermal recovery (steam flooding, fire flooding or hot-water flooding) may cause obvious changes in elastic properties of reservoir rock and pore fluid, leading to an obvious difference in seismic attributes. The difference in time-lapse seismic attributes can be used to map the high temperature area in reservoir, track the high temperature front, and even determine its advancing velocity. However, it is difficult to accurately divide different horizontal ranges defined by reservoir engineering and to determine the longitudinal heterogeneity of the high temperature fronts because the small individual layer is very thin in thickness and low in seismic resolution.