Abstract:

The reservoirs of Yanhu Gas Field are shallow buried with many gas layers, whose gas bearing areas are different. The reservoirs characterized by high porosity and medium to low permeability with no unified gas-water interface are the rare small edge water gas reservoir of ultra-shallow loose sandstone layer. In general, shallow oil and gas reservoirs in China are easy to produce water and sand in the process of exploration and development, of relatively low productivity, great stable production difficulty. In the process of production the formation pressure decreases quickly, and the elastic yield is low. In order to realize the benefit development of small gas field, according to the geological characteristics of the gas field, and on the basis of reasonably division of development layer series and group, the well distribution mode along the axis, occupying high point and dense at the top and sparse at edge for Yanhu Gas Field is determined by referring to the well pattern deployment method of loose sandstone edge water gas reservoir. Then adopting the development from deep to shallow is used to succeed the production by flowback, so as to realize the targets of long-term stable production with less wells and lower cost. Therefore, succession sequence of reasonable reserves, productivity and production for gas fields is ensured. Finally, the best development effects and economic benefit are obtained.

Key words: Yanhu Gas Field, well pattern, loose sandstone, Qaidam Basin, gas-water interface