永新地区高精度地震采集方法的应用效果
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摘要
永新地区油气藏类型属于复杂断块油气藏,具有构造复杂、储层类型多样、含油气层系丰富的特点,该区地震勘探存在的主要问题是低序级断层成像精度不高。为解决低序级断层的成像问题,在该区部署了高精度地震采集,包括以下技术环节:①观测系统设计,设计了面元细分的高精度采集观测系统,该观测系统具有密度高、空间采样均匀、覆盖次数高、道数多的特点;②近地表结构调查,采用表层取心、小折射、单井微测井、双井微测井、地质雷达等近地表结构调查方法,确定了低降速带的厚度、速度、岩性等,建立了工区高速层等厚图,为激发条件选择提供了依据;③接收技术,组合检波选择的主要参数包括组内距、组合基距、组合图形、连接方式;④激发技术,激发技术重点体现在激发井深控制、高程控制、激发药量控制等方面。通过高精度地震采集获得的单炮记录整体信噪比很高,剖面的断层成像质量及信噪比更高,面元越小分辨地质体的能力越强,横向偏移归位精度也越高。
The reservoir type in Yongxing area belongs to complex fault-block reservoir, which is characterized by complex structure, multiple reservoir types and abundant oil/gas-bearing bed set. The main problem of seismic exploration in the area is lower imaging precision of low-sequence faults. In order to solve this problem, the high-precision seismic acquisition was deployed in the area, including following technical links: ①geometry design, designing bin size-fractionized high-precision acquisition geometry that is characters of high density, uniform spatial acquisition, high folds and multiple channels; ②near-surface structure survey, adopting near-surface structure surveying methods such as near-surface coring, shallow refraction, uphole survey of single hole, uphole survey of double holes and geologic radar et al, which determined the thickness, velocity and lithology of weathered and sub-weathered zone, created isopachous map of high-velocity layer in the area, providing foundation for selection of shooting conditions; ③receiving techniques, the main parameters selected in geophone array are geophone interval,group interval,array pattern and connecting pattern;④shooting techniques, which highlights the control of shooting-hole depth, elevation control and shooting charge size control. The total S/N ratio of single-shot record acquired by high-precision seismic acquisition is very high, the imaging quality and S/N ratio of fault on the section are very high; the smaller the bin size, the higher the resolution of geologic body, and the higher the precision of positioning of lateral migration as well.
The reservoir type in Yongxing area belongs to complex fault-block reservoir, which is characterized by complex structure, multiple reservoir types and abundant oil/gas-bearing bed set. The main problem of seismic exploration in the area is lower imaging precision of low-sequence faults. In order to solve this problem, the high-precision seismic acquisition was deployed in the area, including following technical links: ①geometry design, designing bin size-fractionized high-precision acquisition geometry that is characters of high density, uniform spatial acquisition, high folds and multiple channels; ②near-surface structure survey, adopting near-surface structure surveying methods such as near-surface coring, shallow refraction, uphole survey of single hole, uphole survey of double holes and geologic radar et al, which determined the thickness, velocity and lithology of weathered and sub-weathered zone, created isopachous map of high-velocity layer in the area, providing foundation for selection of shooting conditions; ③receiving techniques, the main parameters selected in geophone array are geophone interval,group interval,array pattern and connecting pattern;④shooting techniques, which highlights the control of shooting-hole depth, elevation control and shooting charge size control. The total S/N ratio of single-shot record acquired by high-precision seismic acquisition is very high, the imaging quality and S/N ratio of fault on the section are very high; the smaller the bin size, the higher the resolution of geologic body, and the higher the precision of positioning of lateral migration as well.
引文
[1]陆基孟.地震勘探原理.山东东营:石油大学出版社,1993,130~161
[2]曲寿利.高密度三维地震技术——老油区二次勘探的关键技术之一.石油物探,2006,45(6):557~562
[3]谢里夫R E.勘探地震学.北京:石油工业出版社,1999,166~183
[2]曲寿利.高密度三维地震技术——老油区二次勘探的关键技术之一.石油物探,2006,45(6):557~562
[3]谢里夫R E.勘探地震学.北京:石油工业出版社,1999,166~183
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