典型油藏CO2地质封存中四维地震正演模型研究  

Study of 4D seismic forward model for CO_2sequestration in typical reservoir

作　　者：李琳[1] 马劲风[1] 王浩璠 谭明友[2] 崔世凌[2] 张云银[2] 曲志鹏[2] LI Lin;MA Jin-feng;WANG Hao-fan;TAN Ming-you;CUI Shi-ling;ZHANG Yun-yin;QU Zhi-peng(National and Local Jomt Engineering Research Center of Carbon Capture and Storage Technology,Department of Geology,Northwest University,Xi'an 710069,China;SINOPEC Shengli Geophysical Research Institute,Shandong Dongying 257022,China)

机构地区：[1]二氧化碳捕集与封存技术国家地方联合工程研究中心,西北大学地质学系,西安710069 [2]中国石油化工股份有限公司胜利油田分公司物探研究院,山东东营257022

出　　处：《地球物理学进展》2018年第6期2383-2393,共11页Progress in Geophysics

基　　金：国家高技术研究发展计划(863)课题“二氧化碳地质封存关键技术”(2012AA050103)项目资助.

摘　　要：在CO_2地质封存中,储层中流体饱和度以及地层压力都会随着CO_2的注入而发生变化,相应的纵横波速度也会发生变化.本文首先进行原始状态下横波速度的预测,利用考虑了压力变化的Hertz-Mindlin公式结合Gassmann方程计算横波速度,为了进行对比,又采用不考虑压力变化的Castagna经验公式来进行横波速度的预测.然后,利用这两种方法进行流体替换之后的纵、横波速度的预测,为了体现压力的影响,分别做了(1)利用Hertz-Mindlin公式以及Gassmann方程计算流体替换之后的纵、横波速度;(2)利用Hertz-Mindlin公式以及Gassmann方程计算流体替换之后的纵、横波速度,不考虑压力的变化,即流体替换前后压力不变;(3)利用Hertz-Mindlin公式以及Gassmann方程计算纵、横波速度,仅考虑压力的变化而假设饱和度不变;(4)利用Gastagna经验公式计算流体替换之后的纵、横波速度.在完成流体替换前后纵、横波速度的预测之后,又制作了两层模型以及井模型的AVO正演模型.结果表明,只有同时考虑饱和度以及压力的变化才是最符合实际的,而在该区压力的变化所引起的地震响应的变化远远大于饱和度变化所引起的地震响应.本文的研究区块位于胜利油田正理庄油田高89区,所用资料为该区的全波列测井高94井.During the process of CO2 geological sequestration, fluid saturation and formation pressure in the reservoir can be changed with CO2 injection. In this paper, S-wave velocity of original reservoir was predicted by using Hertz-Mindlin formula combining Gassmann equation. Because there is parameter of pressure in Hertz-Mindlin formula, in order to make a comparison, the Castagna empirical formula that does not consider pressure change is used to predict the S-wave velocity. Then, P-wave and S-wave velocity after fluid substitution of reservoir can be predicted by using these two methods. In order to understand the influence of pressure and fluid saturation, we made the following respectively:(1) P-wave and S-wave velocity after fluid substitution for reservoir was predicted by using the Hertz-Mindlin formula and Gassmann equation.(2) P-wave and S-wave velocity after fluid substitution for reservoir was predicted by using the Hertz-Mindlin formula and Gassmann equation, but the change of the pressure was not considered which is that the fluid pressure is constant before and after replacement.(3) P-wave and S-wave velocity after fluid substitution for reservoir was predicted by using the Hertz-Mindlin formula and Gassmann equation, the change of the fluid saturation was not considered but the fluid pressure is changed before and after replacement.(4)The Gastagna empirical formula is used to calculate P-wave and S-wave velocity before and after fluid replacement. The AVO model of two-layer model and well model was made after the prediction P-wave and S-wave velocity. Results show that the model considering the change of saturation and pressure is the most practical. The seismic response caused by the pressure change is much greater than that caused by the saturation. The research block of this paper is located in the Gao 89 area of Zhenglizhuang oilfield in Shengli oilfield, well log data of Gao 94 well is used to do our research.

关 键 词：压力 饱和度 纵波速度 横波速度 正演模型 四维地震 

分 类 号：P631[天文地球—地质矿产勘探]