湘西碳酸岩山区页岩气地震勘探采集技术研究
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摘要
湖南湘西碳酸盐岩山区不同时期灰岩出露,岩性变化较大,且受风化、淋滤、剥蚀作用,溶洞、裂缝十分发育,导致地震波能量衰减严重,且地震波传播路径和地震波场的复杂,地震原始资料信噪比较低。针对上述问题,采用单/双井微测井相结合的精细浅表层结构调查方法,结合药柱长度和爆炸理论计算出的爆炸半径,动态设计井深激发方式。通过室内模拟计算,研究低频检波器多串、线性等组合接收方式在区内压制面波、折射波、多次折射及侧面波等多波干扰的效果,最终选择2串24个检波器等灵敏度组合及小道距、高覆盖观测等关键采集技术。实践表明,该区选择的观测系统较好的克服了南方岩溶地区地震勘探信噪比低的问题,具有极强的推广价值。
The outcropped limestone of various periods in carbonate rock mountainous region, western Hunan, their lithology varies greatly. Because of weathering, leaching and denudation, bring on karst caves and fissures well developed, thus result in serious attenuation of seismic wave energy, as well as complex wave propagation path, rather low original data signal to noise ratio. In allusion to above issues, using single/double well micro- logging adjoined precise near- surface structure examination combined with seismic charge column length and explosion theory calculated explosion radius, dynamically designed well depth and shot mode. Through indoor simulation, studied low-frequency geophone multiple strings, linear array receiving and the like modes to suppress multi-wave interferences from ground roll, refraction, repeated refraction and lateral wave in the area, finally selected key acquisition technologies of2 strings, 24 geophones equal sensitivity array and small group interval, multifold observation etc. Practices have demonstrated that field setup selected for the area has overcome low signal to noise ratio in seismic prospecting in southern karst regions better, so it is in possession of strong popularization value.
The outcropped limestone of various periods in carbonate rock mountainous region, western Hunan, their lithology varies greatly. Because of weathering, leaching and denudation, bring on karst caves and fissures well developed, thus result in serious attenuation of seismic wave energy, as well as complex wave propagation path, rather low original data signal to noise ratio. In allusion to above issues, using single/double well micro- logging adjoined precise near- surface structure examination combined with seismic charge column length and explosion theory calculated explosion radius, dynamically designed well depth and shot mode. Through indoor simulation, studied low-frequency geophone multiple strings, linear array receiving and the like modes to suppress multi-wave interferences from ground roll, refraction, repeated refraction and lateral wave in the area, finally selected key acquisition technologies of2 strings, 24 geophones equal sensitivity array and small group interval, multifold observation etc. Practices have demonstrated that field setup selected for the area has overcome low signal to noise ratio in seismic prospecting in southern karst regions better, so it is in possession of strong popularization value.
引文
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[2]游先军,戴塔根,息朝庄,等.湘西北下寒武统黑色岩系地球化学特征[J].大地构造与成矿学,2009,33(2):304-311.
[3]蒋裕强,董大忠,漆麟,等.页岩气储层的基本特征及其评价[J].天然气工业,2010,30(10):7-12.
[4]刘振武,撒利明,杨晓,等.页岩气勘探开发对地球物理技术的需要[J].石油地球物理勘探.2011,46(5):810-818.
[5]武建军,贺建明,曾维望.黄土塬区煤田三维采区地震勘探采集技术在王家岭矿区的应用[J].中国煤炭地质,2012,24(1).
[6]蔺国华,倪新辉,杨文强.煤田采区高分辨三维地震勘探激发参数的优选[J].中国煤炭地质,2011,23(10).
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