断层对烃类微渗漏主控作用及异常分布影响的实验模拟研究  

Experimental simulation of the effect of faults on vertical hydrocarbon microseepage

作　　者：王国建[1] 汤玉平[1] 唐俊红[2] 李吉鹏[1] 杨俊[1] 李兴强[1] 

机构地区：[1]中国石化石油勘探开发研究院无锡石油地质研究所,江苏无锡214151 [2]杭州电子科技大学材料科学与环境工程学院,浙江杭州310018

出　　处：《物探与化探》2018年第1期21-27,共7页Geophysical and Geochemical Exploration

基　　金：国家自然科学基金项目(41373121;41072099)

摘　　要：在油气化探中,传统观点认为断层是优势通道,烃类沿断层渗漏形成的化探异常将偏离实际油气藏位置在近地表的垂向投影,这引起了地质界对化探技术预测地下油气藏的质疑。针对上述质疑,以断块油气藏的简化地质模型为基础,研制实验装置,开展断块油气藏烃类通过盖层及上覆地层垂向微渗漏模拟实验,研究了地下断层对烃类垂向微渗漏的影响。结果表明,受断层控制的油气藏,断层不是烃类微渗漏的唯一优势通道,油藏上覆盖层及地层中广泛发育的裂隙或微裂隙系统等都是决定地表化探异常分布的重要因素,烃类垂向微渗漏是客观存的;断层是否是微渗漏的优势通道,取决于断层的封闭性;另外实验结果也证实了圈定油气靶区的最好采样方法是高密度的网格采样。Hydrocarbons in the oil/gas accumulations can seep vertically along the pores, joints, microfractures, fractures, and fauhs to the surface and form geochemical anomalies, which is the theoretical basis of surface geochemical exploration technique. Most of faults underground have big inclination angle, and are not vertically distributed. It is thought that faults are the dominant pathways for mieroseepage, the geochemical anomalies formed through fauhs may deviate from the vertical projection of actual hydrocarbon accumu- lation on the surface. Such a point of view will arouse doubt among geologists about the role of surface geochemistry exploration tech- nique in predicting hydrocarbon accumulations underground. Based on a theoretical model of fault block hydrocarbon accumulation, the authors developed an experimental apparatus to simulate the phenomena of hydrocarbon mieroseepage of the fault block hydrocarbon ac- cumulations. The effect of faults on vertical hydrocarbon microseepage was studied. The results of the simulation experiments show that faults are not the only dominant pathways of hydrocarbon microseepage from the fault block hydrocarbon accumulations, the fractures and micro-fractures system developed widely in the strata are also the important factors to decide the distribution of surface geochemical anomalies, and vertical hydrocarbon mieroseepage exists objectively. Whether faults are the dominant pathways of hydrocarbon micro- seepage or not depends on the sealing capability of faults. The study also shows that the sampling method which is most suitable for de- lineating the oil and gas target is the highest density grid.

关 键 词：微渗漏 断层 优势通道 化探异常 油气藏 

分 类 号：P632[天文地球—地质矿产勘探]