土壤磁性用于油气勘查的一个研究实例

廊坊—固安研究区内两条剖面上的已知油藏上方土壤的磁化率、天然剩磁强度、Q值的异常特征不易辨认。对油田上方土壤样品进行交变退磁清洗后,其剩磁的构成具有明显的特殊性,区别于非油藏上方土壤剩磁的构成。利用这一特点,寻找油气藏效果较好。

A CASE STUDY OF SOIL MAGNETISM USED IN OIL AND GAS EXPLORATION

A case study of soil magnetism used to survey hydrocarbon is described in this paper.Two sections over the oil field in Langfang—Guan depression was studied and 164 soil magnetism samples were collected from 59 sites.Magentic susceptibility (MS) and nature residual magnetism (NRM) were tested,but the anomalies of MS,NRM could not be easily associated with oil wells.Alternating demagnetization for part of samples was done and,as a result,a specific demagnetization curve over the oil well was found,which is different from the curve over dry well.Amineralization model is advanced,in which magnetite is developed over hydrocarbon seepage,and hematite is distributed over the formation that contains no hydrocarbon.