摘要
扶余油层的地质、地球物理特征表现为:储层薄、空间多期叠置及地震分辨率不足、扶余油层顶面(T2)强反射对下部地层具有屏蔽作用;砂岩的速度和密度高于泥岩,但差异较小,且由于砂泥岩薄互层的调谐效应,致使波阻抗与砂岩的对应关系不明显;由自然伽马(GR)和电阻率曲线可以区分砂岩和泥岩。为此,选择GR进行波形指示模拟。地震波形指示模拟的基本思想是在等时格架约束下,利用地震波形的横向变化代替变差函数表征储层的空间变异性,在贝叶斯框架下有效结合地震、地质和测井信息,采用分频反演策略逐步提高反演结果的分辨率,即:由测井资料插值求取低频成分,利用地震谱模拟反演获得中频成分,由波形相控模拟、随机模拟分别提供确定性高频成分、随机性高频成分,合理加入高频成分大幅提升了储层预测的纵向分辨率。实际数据应用效果表明:(1)波形指示模拟在提高纵向分辨率的同时有效提高了横向分辨率,波形指示模拟产生的自然伽马数据体分辨率高,能够预测厚度大于2.4m的单砂体展布,但存在多解性,须在钻井数据指导下确定地质甜点,以指导水平井部署及随钻导向。(2)有效样本数和最佳截止频率是波形指示模拟的重要参数,决定了反演效果,须经试验反复筛选。
The geologic and geophysical characteristics of Fuyu reservoirs are as follows:(1)The reservoirs are thin and superposed;(2)Their seismic resolution is low and T2 events(strong top reflections)shield the reservoirs;(3)Both the velocity and the density of the sandstone are higher than that of the mudstone,but the difference is tiny;(4)The corresponding relationship between the impedance and the sandstone is not obvious due to the tuning effect of thin interbedded sandstone and mudstone;(5)Gamma ray(GR)and resistivity logging curves can distinguish the sandstone from the mudstone.Finally,GR logging curves were chosen as the characteristic curves used in the seismic motion simulation(SMS)process.The basic ideas of seismic motion simulation are that,constrained by sequence stratigraphic framework,the lateral changes of seismic waveform instead of variation function is used to express the spatial variation of reservoir;constrained by the Bayesian framework,and considering seismic,geological and logging information,a frequency-divided inversion strategy is taken to gradually improve the resolution of inversion results,namely to calculate the low frequency components through logging interpolation,conduct seismic spectrum simulation inversion to obtain intermediate frequency components,and run waveform controlled simulation and random simulation to provide deterministic high-frequency components and random high-frequency components.The reasonable high-frequency components help greatly improve the vertical resolution of the reservoir prediction result.The application of this method to real data shows that:(1)SMS can improve both vertical resolution and lateral resolution;GR SMS results have so high resolution that they can predict single sand bodies more than 2.4 m thick.However,there are multiple solutions and it is hard to select the best solution.Drilling data should be used to select,and only the solution selected can be used to predict geologic sweet points for future deployment and drilling of horizontal wells;(2)Effective samples and the best cutoff frequency,two important parameters of SMS,which decide the quality of inversion,should be chosen through repeated tests.
作者
谢春临
李永义
陈志德
扈玖战
田梦
王晓杨
XIE Chunlin;LI Yongyi;CHEN Zhide;HU Jiuzhan;TIAN Meng;WANG Xiaoyang(Exploration and Development Research Institute of Daqing Oilfield Company Ltd.,Daqing,Heilongjiang 163712,China;Daqing Research Institute of Geophysical Exploration,BGP,CNPC,Daqing,Heilongjiang 163000,China;The Sixth Oil Production Plant of Daqing Oilfield Company Ltd.,Daqing,Heilongjiang 163114,China)
出处
《石油地球物理勘探》
EI
CSCD
北大核心
2021年第3期564-573,I0012,共11页
Oil Geophysical Prospecting
基金
国家科技重大专项项目“松辽盆地致密油开发示范工程”(2017ZX05071)资助。
关键词
扶余油层
河道砂岩
波形指示模拟
分频反演
有效样本数
最佳截止频率
Fuyu reservoir
channel sandstone
seismic motion simulation
frequency-divided inversion
effective samples
best cut-off frequency
