Abstract：An upsurge of direct oil detection using Affinity System gravity method has been sponsored in Chinese hydrocarbon exploration since 1991.As a result of the inventor's top exaggeration and quite many blind believers' propagation,the technique has been described as an accurate,easy,cheap and efficient technique,by which the success rate of oil discover y may be 95%in America.Because of blindly believing the inventor` s exaggeration,some Chinese important personages have applied the technique to some oil exploration areas in China.As a matter of fact,the Affinity System is unreliable in theory.It is utterly groundless that Affinity System can directly observe "weak gravity field component "relating to hydrocarbon.It is necessary for us to clear some geophysicists' minds about the unreliabilities in theory and practice.Affinity gravimeter offers very poor observation data in some oil fields,and the mis-ties at intersecting points in final result are often higher than the abnormal rangeabilities which are adopted to detect oil,gas and water.What is more,the gravimeter gives very different data in repeated observations in an area.For example,the favourable anomaly area mapped in reconnaissance even disappears in following detailed exploration.So this gravimeter is very unreliable.We can say from Affinity System data that Affinity technique is basically a vertical gravimetric gradient survey with poor accuracy,and can't be called as a new dlrect oil detection technique at all.Unlike Affinity System technique,Russian GONG technique is an explorative experiment.The inventor shows people his method and opinions frankly,but he likely goes astray in theory.In addition,too much subjectivity exists in determining "recovered gravity anomaly".It is demonstrated that the background anomaly resulting from severe lithologis variations of subsurface sandstone and shale is much stronger than the weak negative anomaly related to hydrocarbon.Generally speaking,direct oil detection by gravity is unfeasible,and direct gas detection by gravity is possible only when gas reservoir is shallow,thick and was formed in late geological age.
李庆忠. 评艾菲微重力直接找油兼论GONG直接找油[J]. 石油地球物理勘探, 1997, 32(2): 277-302.
Li Qingzhong. Evaluation of direct oil detection using Affinity System and comment on GONG direct oil detection. OGP, 1997, 32(2): 277-302.
