摘要
常规叠前弹性阻抗(EI)反演识别流体的方法难以满足预测致密砂岩储层的要求,为此进一步推导了广义弹性阻抗(GEI)方程,表达为纵横波速度比v_P/v_S(可计算泊松比σ)和一种新的流体识别因子f/v_S(Gassmann流体项与横波速度的比值)的计算公式,可以直接反演出v_P/v_S(或σ)和f/v_S参数,避免了间接计算的累积误差。建立正演模型,分析弹性阻抗方程和广义弹性阻抗方程的精度可知,在鄂尔多斯盆地苏里格气田致密砂岩储层中,广义弹性阻抗方程的精度比弹性阻抗方程的精度高。分析测井资料多项参数后认为,泊松比σ为岩性识别最敏感参数,f/v_S为流体识别最敏感因子。对研究区进行正反演计算,通过正演模拟验证了广义弹性阻抗方程的精度,通过反演获得了v_P/v_S(或σ)和f/v_S数据,对反演数据进行分析研究,进一步验证了f/v_S对致密砂岩储层流体识别的可靠性;同时可知,流体因子f/v_S的识别精度虽受噪声影响,但可以清晰地检测出流体,具有一定的抗噪性。
It is difficult to predict tight sandstone reservoirs using conventional elastic impedance(EI)inversion for fluid identification.Therefore,a generalized elastic impedance(GEI)approximation equation was derived as a formula of two parameters,namely a parameter of the P-and S-wave velocity ratio and a parameter of a new fluid factor(i.e.,the ratio of the Gassmann fluid term to S-wave velocity).The two parameters can be directly calculated by inversion,avoiding cumulative errors inherent to indirect calculations.The P-and S-wave velocity ratio parameter can be used to obtain Poisson s ratio.A forward modeling test revealed that the GEI formula had a higher precision than the EI formula for tight sandstone reservoir prediction.From a comparative analysis of multiple parameters from logging data in the research area,Poisson s ratio is the most sensitive parameter for lithological identification,and the new fluid factor is the most sensitive parameter for fluid identification.Field seismic data inversion in the Sulige gas field in the Ordos Basin,China,verified the reliability of the new fluid factor for fluid identification at a tight sandstone reservoir,and indicated that the new fluid factor exhibited a degree of anti-noise properties.
作者
贾凌云
李琳
王千遥
马劲风
王浩璠
王大兴
JIA Lingyun;LI Lin;WANG Qianyao;MA Jinfeng;WANG Haofan;WANG Daxing(National&local Joint Engineering Research Center of Carbon Capture and Storage Technology,Department of geology of Northwest University,Xi an 710069,China;China Coal Technology Engineering Group XI AN Research Institute,Xi an 710077,China;Research Institute of Exploration and Development,Changqing Oil field Company,PetroChina,Xi an 710018,China)
出处
《石油物探》
EI
CSCD
北大核心
2018年第2期302-311,共10页
Geophysical Prospecting For Petroleum
基金
国家高技术研究发展计划(863计划)(2012AA050103)资助。
关键词
广义弹性阻抗反演
致密砂岩
岩性识别
流体因子
弹性阻抗
流体项
泊松比
GEI inversion
tight sandstone
lithological identification
fluid factor
elastic impedance
fluid item
Poisson s ratio
