Deep and horizontal drilling technologies for natural gas

For the exploration and exploitation of natural gas resources in deep and unconventional reservoirs, deep and horizontal drilling are the key technologies. This chapter aims to introduce the key deep and horizontal drilling technologies for natural gas. This chapter begins with a classification of the major types of natural gas wells, such as vertical wells, directional wells, horizontal wells, and extended-reach wells, and briefly introduces their main characteristics and application situations. Then, the key technologies for deep and horizontal drilling are presented in detail. These include casing program design, managed pressure drilling, underbalanced drilling, vertical drilling system, high efficiency drill bits, penetration rate increasing technologies, high-temperature and high-pressure drilling fluids, directional technologies, measurement while drilling, geo-steering technologies, and drilling risk monitoring and management. Finally, the deepest and longest wells all over the world are identified from literature to show the application and recent achievements of deep and horizontal drilling technologies in the petroleum industry, and the challenges of deep and horizontal drilling are briefly discussed.