琼东南盆地超深水浅部气藏地球物理识别技术

Geophysical Identification Technology of Ultra Deep Water and Shallow Gas Reservoirs in Qiongdongnan Basin

浅部气赋存于浅部成岩强度低的未固结岩石内,其岩石物理特征、地震反射特征都区别于深层已成岩岩石.为建立浅部气藏地球物理识别技术,笔者利用浅层测井数据分析该盆地浅层岩性、流体性质对岩石速度、密度、纵横波速度比的影响,明确浅部气层敏感弹性参数.在此基础上,利用颗粒接触岩石物理模型进行浅层岩石物理建模,获得了浅部气层和水层的纵波速度、AVO特征随孔隙度变化模板.在此基础上,利用地震正演手段查明了浅部气层地震反射特征,明确了浅部气层识别标志,并从地震反射结构特征、反演弹性参数特征、AVO特征入手实现了浅部气层的识别.首次将Direct Hydrocarbon Identifier by Induced Polarization(DHIP)勘探技术应用于浅部气藏饱和度预测,实现了研究区浅部气藏饱和度定性预测.该套浅部气藏评价技术是目前琼东南盆地浅层勘探的首次应用,对该盆地后续浅部气藏勘探具有建设性意义.

Shallow gas occurs in unconsolidated rocks with low diagenetic strength in the shallow part,and its petrophysical characteristics and seismic reflection characteristics are different from those of deep diagenetic rocks.Using shallow logging data,it analyzes the effects of shallow lithology and fluid properties on rock velocity,density and P-S wave velocity ratio in the basin,and defines the sensitive elastic parameters of shallow gas reservoir.On this basis,the particle contact petrophysical model is used for shallow petrophysical modeling,and the variation templates of P-wave velocity and AVO characteristics of shallow gas and water layers with porosity are obtained.Based on the seismic reflection,the seismic reflection characteristics of shallow gas layer are identified,and the characteristics of shallow gas layer are identified by using the seismic reflection method.Direct Hydrocarbon Identifier by Induced Polarization(DHIP)exploration technology is applied to the saturation prediction of shallow gas reservoir for the first time,and the qualitative prediction of shallow gas reservoir saturation in the study area is realized.The shallow gas reservoir identification technology has been applied in the exploration of Qiongdongnan Basin,which is of constructive significance to the subsequent shallow gas reservoir exploration in the basin.