Pressure sealing technology of open holes in suprasalt structures of Tahe Oilfield

The scheme that uncovers the open holes of suprasalt structures and the salt beds in the same formation is adopted in this paper.Because of the leakage of the fractured formation and the absorbent formation and the complex formation pressure,pressure sealing technology becomes one of the key technologies in developing the hydrocarbon reservoir under the salt-gypsum bed of Carboniferous Bachu Formation of Tahe Oilfield.This paper introduces the lithologic features of the formation in suprasalt structures of Tahe Oilfield,analyzing the leakage types and their regional distribution features,describing the plugging technology used in the wells with salt beds of the oilfield,and summarizing the experiences and lessons obtained from applying the former plugging technologies.It is proposed that the types,grain diameters,density,and rates of plugging materials be selected for formations with different leakage features.As a result,two typical plugging formulas are optimized and corresponding measures are adopted,obviously increasing the primary success rate of plugging.Practices show that it is feasible to apply the pressure sealing technology to the long open holes in suprasalt structures of Tahe Oilfield,which shortens the operation time obviously and meets the need of drilling in salt beds.