Study and application of segmented floating cementing technology for large-displacement 3D S-shape horizontal well in coalbed methane

Due to significant variations in coal seam reservoir conditions and the continuous increase in horizontal wellbore lengths, cementing technology for coalbed methane（CBM） horizontal wells in complex geological environments still faces some challenges. Further improvements are required in reservoir protection during cementing operations, casing running, and cement slurry replacement processes to enhance cement quality and ensure safety and engineering integrity during multi-stage fracturing operations in later stages of horizontal well development. Taking Baode Mine as a case study, this paper investigates and proposes a segmented floating method combined with pressure compensation casing runing technology for large-displacement 3D S-shaped coalbed methane horizontal wells. The research optimizes a graded non-uniform density cement slurry system and implements low-pressure displacement cement grouting techniques, ultimately developing cementing technologies suitable for low-pressure coal reservoirs. The successful implementation of a 1L horizontal well in the No.11 coal seam at Baode Mine has demonstrated that large-displacement 3D S-shaped horizontal drilling technology enables secure casing running at the bottomhole, effectively protecting coal reservoirs while ensuring wellbore integrity in gas-bearing formations. This breakthrough establishes a perfect well structure for coalbed methane development. Baode Mine’s multi-layered gas-rich coal seams make it ideal for applying this advanced drilling technique, allowing multi-layer gas resource development through the “well factory” integrated model.