高精度地表油气化探技术的发展及应用--以济阳凹陷垛石桥地区土壤酸解烃为例

摘要

The soil acid-extraction hydrocarbon (SAEH) technique is an important method in surface geochemical exploration for oil and gas, and is frequently used in petroleum exploration. However, multi-solution of the index influences its application. In order to provide high-precision techniques and methods for petroleum exploration, an improved soil acid-extraction technique was used to determine concentrations and carbon isotope ratios of the SAEHs in the soil samples from Duoshiqiao area, Jiyang depression. The result shows that the concentration of methane in SAEHs is influenced by many factors, and its variation has no obvious relationship to the subsurface oil or gas reservoir, whereas the concentrations of relatively heavy molecular weight hydrocarbons (C2~C5) in the SAEHs can effectively reveal the contribution of oil or gas migrated from subsurface reservoir. In addition, the compositions of SAEHs indicate that these hydrocarbons are mainly sourced from the oil reservoirs and partly from condensate reservoirs, which are coinciding with the actual geological background. Therefore, the advanced acid extraction technique can provide an effective method for geochemical exploration for petroleum in complex petroleum-bearing areas.%酸解烃技术是油气化探的一个重要方法，在常规的油气化探中被普遍应用，然而多解性一直影响其应用效果。本文选择济阳凹陷垛石桥地区作为研究区，利用改进的酸解烃技术，分析研究区已知背景区和产油气区土壤中的酸解烃含量及其碳同位素特征，以验证改进酸解烃技术在复杂含油气区块油气化探工作中的有效性，为油气化探提供高精度的技术方法。研究结果表明，垛石桥地区地表土壤酸解烃中甲烷的含量受干扰因素较多，与下伏油气藏没有明显的对应关系；而乙烷和丙烷等重烃含量与下伏油气藏的对应关系较好，可以较好地揭示深部油气运移的贡献。另外，该地区土壤酸解烃的组成特征指示其深部油气源以油藏为主，部分为凝析油藏，与实际地质情况较为吻合，表明改进的酸解烃技术可以作为复杂含油气区块指示深部油气藏的有效化探方法。