川西坳陷中深层裂缝的识别与预测
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摘要
川西坳陷中段中深层储层多已致密化 ,天然气的聚集及产出主要依赖于裂缝系统。常规测井曲线特征显示 ,中下侏罗统和须家河组储层裂缝存在明显的区别 :前者自然电位为弱负异常 ,“中子挖掘”效应明显 ;后者则以整体差值高、跳波现象频繁为特征。另外 ,中深层储层的低频强振幅并不像浅层蓬莱镇组那样与裂缝存在良好对应关系。由此 ,通过常规测井、BP神经网络和地震响应方法可大致识别出裂缝发育段 ,根据上述特征 ,合兴场构造南部须家河组和千佛崖组可能是裂缝发育带。
Most of the median deep burial strata in the middle section of West Sichuan Depression had been compacted, so that accumulation and output of natural gas are mainly dependent on fracture systems. As shown by conventional logs, the reservoir fractures in Middle Lower Jurassic are different from those in Xujiahe Formation. The SP of the former displays weakly negative anomalies with obvious“neutron dig”effect; and that of the latter is characterized by the high departure values on the whole and the frequent “wave jumping”phenomena. In addition, the low frequencies and high amplitudes against the median deep burial strata are worse correlated with fractures than those against the shallow burial Penglaizhen Formation. Therefore the fracture developed intervals may be roughly identified by use of these methods as conventional logs, BP neural network and seismic responses. According to these characteristics mentioned above, it was predicted that the fracture developed intervals may be able to be found out in the Xujiahe Formation and Qianfoyan Formation in the south part of Hexingchang structure.
Most of the median deep burial strata in the middle section of West Sichuan Depression had been compacted, so that accumulation and output of natural gas are mainly dependent on fracture systems. As shown by conventional logs, the reservoir fractures in Middle Lower Jurassic are different from those in Xujiahe Formation. The SP of the former displays weakly negative anomalies with obvious“neutron dig”effect; and that of the latter is characterized by the high departure values on the whole and the frequent “wave jumping”phenomena. In addition, the low frequencies and high amplitudes against the median deep burial strata are worse correlated with fractures than those against the shallow burial Penglaizhen Formation. Therefore the fracture developed intervals may be roughly identified by use of these methods as conventional logs, BP neural network and seismic responses. According to these characteristics mentioned above, it was predicted that the fracture developed intervals may be able to be found out in the Xujiahe Formation and Qianfoyan Formation in the south part of Hexingchang structure.
引文
1 雍世和,张超谟.测井数据处理与综合解释.山东东营:石油大学出版社,1996
2 刘瑞林.用神经网络学习识别化探及物探数据.石油物探,1994;(1):33～35
3 王金琪.川西坳陷须家河组T3x气藏再认识.天然气工业,2002;(2)
4 杨振武,李显贵.新场、东泰、合兴场三维地震相干及应用.石油地球物理勘探,2000;35(3):339～345
2 刘瑞林.用神经网络学习识别化探及物探数据.石油物探,1994;(1):33～35
3 王金琪.川西坳陷须家河组T3x气藏再认识.天然气工业,2002;(2)
4 杨振武,李显贵.新场、东泰、合兴场三维地震相干及应用.石油地球物理勘探,2000;35(3):339～345
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