Technology and Practice for Horizontal Well Development in the He-1 Gas Reservoir of Daniudi Gas Field

Due to the fact that horizontal wells in He-1 Gas Reservoir in Daniudi Gas field featured long drilling cycles, low yields and unstable production, a study was conducted on the horizontal well drilling and production technique.Through the analysis of existing horizontal wells that used similar casing programs, drilling fluids, fracturing parameters and gas recovery etc, the key factors restricting the development were defined, including mainly the ideal casing program, fracturing parameters and form properties.A pilot test of staged fracturing with multiple external casing packers and foam scrubbing was conducted in a φ152.4 mm hole, an optimized horizontal well drilling technology for the slim holes with three casing programs and adopted.Composite drilling and anti-sloughing drilling fluids were developed, which reduced the average drilling cycle by 7.79%.On this basis, the horizontal well fracturing technique suitable for He-1 gas reservoir was proposed, it has a success rate of 98.5%, and the average post-fracturing open flow poterntial was 4.9 times of that in vertical wells.The critical liquid carrying model was established, and the gas recovery by water drainage with velocity string was tested, which indicated a production time efficiency increased by 8.49%.Application results showed that the composite drilling in φ152.4 mm hole could improve the ROP, the staged fracturing with multiple external casing packers could be an effective way to recover hydrocarbons in the He-1 Gas Reservoir, and gas recovery by water drainage using a foam agent could keep the production in the gas field stable.