Hailar Basin Chagan Noel Depression Comprehensive Evaluation Of The Petroleum Geology

As we know, Chagannuoer depression situated on the southwest of Hailaer basin. Its east is Cuogang uplift, its west is Hanwula uplift, its north is Hulunhu depression, and it extended its south boundary toward Mongolia. Its area is about 1420km2 in China. Geophysical Exploration Company of Daqing interpreted the 2D seismic data in 2000, and they have a original cognition about the basic geological enviorment and petroleum geological model. However, Chagannuoer depression is in beginning of exploration, the explorers have some geological questions about Chagannuoer depression. For example, there is not a complete sequence stratigraphy conception and petroleum geological model, there is not a clear order aobut the fault and the character of Chagannuoer depression, there is a reasonable geological history, there is a factual evaluation about oil formation, migraton and accumulation in Chagannuoer depression. All of these questions restricted the exploration in Chagannuoer depress. Based on the old research the sequence stratigraphy frame is builded by seismic, log and geochemistry means. At the same time the tectonic characters were discussed particularly. It is clear aobut the evolvement of Chagannuoer depression. Hydrocarbon generating quantity, hydrocarbon yiele and hydrocarbon accumulating quantity were calculated in this paper. At last two favorable hydrocarbon accumulation zone were forecasted in Chagannuoer depression. Zhalainuoer group of K1 is a super sequence, which can be devided into five third order sequences. Chagannuoer depression consists of palaeoslope zone, sag, and fault terrace belt by tectonic analysis. A typical character of faulting in fault terrace belt and palaeoslope is intermissive. Chagannuoer depression has two tectonic cycles: rifting stage and depressing stage. During rifting stage the super sequence I was deposited, which consisted of original extension, strong extension, quick subsiding stage, steady extension and shrinking stage. Sequence I was deposited during original extension; sequence II was deposited during strong extension; sequence III and IV were deposited during quick subsiding stage; lastly K1y was deposited during shrinking stage. Total hydrocarbon generating quantity was about 5.32×108t, and accumulating quantity was about 0.56×108t. All evidences show that it is possible that there is about 0.3~0.5×108t oil pool in Chagannuoer depression. Chagannuoer depression is a typical small continental lake basin, which petroleum migration has its own character. There were three petroleum migration pattern, which were migrating along big fault, migration like a ladder and migrating along unconformity. There may be several styles of pool, such as fault block reservoir, hydrocarbon accumulation sealed by backward faults, fault-nose pool, sand lens reservoir, stratigraphic unconformity reservoir, buried hill hydrocarbon accumulation, updip pinch hydrocarbon accumulation, and stratigraphic overlap reservoir. At last two favorable hydrocarbon accumulation zones were forested based on our researching. One is palaeoslope zone, another is fault terrace belt.