Abstract:

The proved carbonate hydrocarbon reservoirs in burial hills of Cambrian have shown the huge exploration potential;however because the basin has done through multiple structural events,the reservoirs formed previously in Cambrian were affected by later structural events and they were a山usted，transformed，destroyed and reformed.  The complexity of the superimposed basin leads to a loss to present theories.  At present，the success ratio of exploration about 25% in Cambrian is low. This paper discusses the failure reasons of these 15 holes from the geological process of hydrocarbon enrichment by the methods of “functional elements matching，structural process superimposing and facies-potential-sources coupling at late stage"，and tries to bring to light the hydrocarbon accumulation mechanism to improve the efficiency of exploration.  The results turns out that，80 percent of abortive holes locating out of the promising accumulation districts failed because they did not match functional factors; 7 percent of them locating out of promising exploration areas failed because the previous reservoirs were destroyed in the later structural events;13 percent of them failed because they did not meet the facies-potential-source couple in late stage.  The methods successfully explained the reasons of failure holes in Cambrian in the Tarim basin and proven the feasibility and validity of the new theory and prediciton methods, showing a great practical significance to the future petroleum exploration.

Key words: Tarim basin, Cambrian, failure, functional elements matching, structural process superimposing, facies-potential-sources coupling at late stage