白音查干凹陷地层与构造研究新认识及其勘探成果

New knowledge from stratigraphy and structure studies and its exploration results in Baiyinchagan sag

白音查干凹陷已有近 2 0年的勘探历史。截至 2 0 0 2年底 ,该地区已钻探井 4 2口 ,累计上报探明含油面积 4 1km2 、探明石油地质储量 16 0× 10 4 t ,勘探效果不理想。针对勘探中存在的问题 ,依据大量的三维地震资料 ,结合古生物及层序地层研究成果 ,对该地区地层重新进行了划分与研究 ,并运用全三维地震解释技术对该地区的断裂系统和重点构造 (桑合构造 )进行了重新认识与解释 ,提出了主要勘探目的层上移的新认识。钻井证实 ,桑合构造是目前白音查干凹陷已发现的最富集的含油区块 ,其主要含油层系为原主要勘探目的层下白垩统腾格尔组之上的都红木组一段。该构造 2 0 0 3年上报含油面积 3 6km2 、探明石油地质储量 5 2 6× 10 4 t。基于新认识的勘探成果 ,将推动该地区油气勘探的深入进行。

Baiyinchagan sag had experienced 20 years petroleum exploration by the end of 2002, and it was not very successful because 42 exploration wells drilled only resulted in 4.1km 2 of oil*.bearing area and 160×10 4 t of proved geologic oil reserves during the period. Therefore, the stratigraphic section is divided and analyzed again according to a lot of 3D seismic data and in combination with palaeontology and sequence stratigraphy results, and the fault system and a major structure (Shanghe structure) are researched and interpreted again by using a technique of whole 3D seismic interpretation, by which a new idea that the main exploration targets occur in shallower intervals can be proposed. By drilling, it has been confirmed that Shanghe structure is the richest oil*.bearing block in Baiyinchagan sag, where the main target is Member 1 of Duhongmu Formation (K 1bd 1) above Lower Cretaceous Tengger Formation (K 1bt) , the previous main target.In 2003, 3.6km 2 of oil*.bearing area and 526×10 4 t of proved geologic oil reserves were discovered on the structure. The exploration results based on the new knowledge will prompted future intensive petroleum exploration in the sag.