Abstract:Reservoir with low porosity and permeability accounts for 93% of all reserves of the E Sea； thus， enhancing the recovery of low and ultra-low per permeability gas fields has become an importance subject in the exploration and development of oil and gas fields. Horizontal branch well technology， which has been deployed and proven to be fruitful in enhancing gas field recovery at home and abroad， plays a significant role in increasing the recovery of low and ultra-low per permeability gas fields. Horizontal branch well technology， a fusion of multiple drilling technology including horizontal well and side-tracking， is a hot technology in oil development industry. It has been implemented in several fields in the E Sea， and proven to be an effective means to develop low permeability gas fields. As a result， it is of much importance to conduct in-depth study and summarization of the technology. This paper has analyzed the technology in depth and summarized its key application points in the E Sea X field， which can assist in further promotion and application of this technology in low permeability oil and gas fields in the E Sea.

Abstract:As an important technical approach to control coal mine water hazard, drilling technology has been widely used. The application of coal mine water hazard control technologies, such as large diameter drainage well drilling, ground floor multi-branch horizontal wells by surface directional drilling and grouting reinforcement and reconstruction, underground directional drainage drilling, grouting to seal water inrush passage drilling and rapid rescue drilling of mine inrush disaster, has received good effects. Further development of drilling equipments for water control and the research on related drilling technologies should promote coal mine water hazard control.