The Challenges of Drilling Technology in the Deep Marine Carbonate Reservoir in China

摘要

It is estimated that the oil and gas reserves in the marine strata was 72％ of all the oil and gas reserves in the world.In recent years,Chinese oil companies have focused on the exploration and development activities of the marine carbonate reservoir,and have achieved some important breakthroughs in Tarim,Sichuan and other regions in China.These new discoveries suggest the large potential of developing marine oil and gas resources in China,and will greatly change the situation and strategy of hydrocarbon exploration and development in China.In contrast with the terrestrial reservoir,the Chinese marine carbonate reservoir has many basic geological features such as old age,deep burial (＞5000 m),the development of cracks and holes,anomalous formation temperature and pressure,and richness in hydrogen sulfide gas.These features increase the probability of problems with drilling marine carbonate reservoirs,such as sudden fatal accidents,the long cycle of drilling,the high cost,and the hazards of oil and gas wells production.In China since 2003,four accidents have occurred related to drilling marine carbonate reservoirs.This reflects that,regarding marine carbonate reservoirs,the basic theory of drilling is underdeveloped,and the preparations of drilling and completion technologies are also limited.Thus the revenue of exploration and development of marine carbonate reservoir is reduced.This paper discusses the three main challenges of drilling technology in the Chinese deep marine carbonate reservoir,in the interest of offering some references to the drilling engineering.