枪口节流作用和热传导作用对海上勘探气枪子波的影响  

Effects of gun ports throttling and heat conduction on air gun signature in offshore seismic exploration

作　　者：李国发[1,2] 曹明强[1,2] 陈浩林 倪成洲 郭顺林 

机构地区：[1]油气资源与探测国家重点实验室中国石油大学,北京102249 [2]CNPC物探重点实验室中国石油大学,北京102249 [3]中油东方地球物理公司,天津300280

出　　处：《特种油气藏》2011年第2期26-28,136,共3页Special Oil & Gas Reservoirs

基　　金：国家"973"课题"非均质油气藏地球物理探测现场实验"(2007CB209608);中石油科技创新基金项目"基于地层反射结构统计表征的非线性反演方法研究"(2010D-5006-0301)

摘　　要：海上地震勘探多使用气枪震源进行激发,气枪子波的研究对于海上地震采集和资料处理具有十分重要的意义。枪口的节流作用和热传导作用影响着气枪子波的特性。为此,基于自由气泡理论,考虑气枪机械因素以及气泡周围环境的影响,建立了气枪震源子波数值模型。利用该模型就枪口节流作用和气泡壁的热传导作用对气枪子波的影响进行了分析。结果表明:枪口节流作用与气枪枪口面积有关,影响气枪内高压气体的释放速度,进而削减气枪子波的主脉冲;气泡振动加快了气泡周围流体的运动速度,气泡壁的热传导作用随之加强,气泡损失更多的能量,气泡振动衰减速度加快。Air guns are widely used as shooting source in offshore seismic exploration.The research on air gun signature is very important to offshore seismic data acquisition and processing.The effects of throttling and heat conduction at gun ports affect the characteristics of air gun signature.Based on bubble oscillation theory,a numerical model is established to simulate air gun signature with consideration of air gun mechanical factors and the environmental factors around the bubble.The influence on signature is analyzed in respects of gun ports throttling and heat conduction across bubble wall by using this model.The results indicate that gun ports throttling are related to air gun ports area which can affect the velocity of high pressure air released from air gun and reduce the peak of air gun pulse;bubble oscillation accelerates fluid movement around the bubble and enhances heat conduction across bubble wall,the bubble loses more energy,and bubble oscillation attenuates rapidly.

关 键 词：节流作用 热传导作用 海上勘探 子波 气泡振动 

分 类 号：TE51[石油与天然气工程—油气田开发工程]