油气模型的重力梯度张量研究  

Study on Gravity Gradient Tensor of Oil-Gas Model

作　　者：蒋甫玉[1] 高丽坤[2] 黄麟云[3] 

机构地区：[1]河海大学地球科学与工程学院,南京210098 [2]南京大学地球科学与工程学院.南京210093 [3]江汉油田勘探开发研究院计算中心,湖北潜江433126

出　　处：《吉林大学学报（地球科学版）》2011年第2期545-551,共7页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(90815020)

摘　　要：以位场数据处理中的傅里叶变换为出发点,推导出由重力异常计算梯度张量的余弦谱变换公式,进而通过离散余弦变换实现梯度张量的数值计算。对不同贮油厚度的三度体球冠模型梯度张量的研究表明:当油气含量较小时,其梯度张量与均匀三度体球冠模型所表现出的特征相似,Vxx、Vyy呈'两高夹一低'的对称特征;Vxy总体上呈现出向中心变小的趋势,在4个边缘的中部分别有4个呈两两对称的相对较高值;Vzz四周低,中间高;Vzx、Vzy呈现出西低东高和南低北高的特征。而当贮油厚度逐渐增大时,Vxx、Vyy的形态则渐变为'两低夹一高';Vxy在四周有相对低值,中部有极大值;Vzz四周高,中间低,变化更加尖锐;Vzx及Vzy呈西高东低和南高北低的特征。对三度体球冠模型重力梯度张量的研究,可以为寻找储油背斜构造提供理论依据。A cosine transform technique has been developed to calculate the complete gravity gradient tensor from pre-existing vertical gravity data which provides an alternative determination of the gravity gradient tensor components.Gravity gradient tensor components are computed for different thickness of three dimensional oil sphere-coronal models.The characteristics of gradient tensor are similar to homogenized three dimensional sphere-coronal model when the thickness of oil is low,and the components of Vxx and Vyy show the symmetric characteristics of ＂one low value between two high values＂.Vxy reduced gradually and reached minimum in center,there are four higher values in the center of four boundaries and show symmetric characteristic.Vzz component shows high in the middle and low on all sides;Vzx and Vzy are lower in west and south,and higher in east and north,respectively.However,when the thickness of oil is great,Vxx and Vyy show the symmetric characteristics of ＂one high value between two low values＂.Vxy accreted gradually and reached maximum in center.Vzz is lower in the middle and higher on all sides,and changed more acute.Vzx and Vzy are higher in west and south and lower in east and north,respectively.The studies on gravity gradient tensor of three dimensional oil sphere-coronal models could provide a theory basis for finding storage anticline tectonic.

关 键 词：余弦变换 三度体球冠 梯度张量 贮油厚度 

分 类 号：P631.1[天文地球—地质矿产勘探]