Acidizing Technique for Carbonate Reservoirs with Super-high Temperature in Bohai Sea

Buried hill carbonate reservoirs are the key areas of oil and gas exploration and development in Bohai Sea, while acidification is essential for exploration and development of carbonate reservoirs. In the process of studying the exploration and development of Buried hill carbonate reservoirs with super-high temperature in Bohai Sea, a new acidizing technique "non-acid chelating + high temperature retarded acid" was developed for super-high temperature carbonate reservoirs based on the characteristics of super-high temperature, deep burial, poor physical property, strong heterogeneous, long testing layer and containing hydrogen sulfide with combination of the corresponding fundamental research and technological supporting research. The non-acid chelating system can reduce the formation temperature and reaction rate, achieve the deep penetration. The high temperature retarded acid can activate the natural fracture and distribute the acid uniformly. Then the acidizing technique for carbonate reservoirs with super-high temperature in Bohai Sea has been formed. This technique has been successfully applied in Well A. The stimulation effect was remarkable, and the test production rate of gas increased by 55 times.