The Mahu Fengcheng Formation shale oil reservoir features deep burial depths，complex pressure systems and strong formation heterogeneity，and such complex geological conditions severely restrain the drilling efficiency of horizontal wells，highlighting the urgency of research on technologies enhancing rate of penetration（ROP）. Based on rock mechanical tests，whole-rock mineral composition analyses and geological characteristics of the Mahu Fengcheng Formation，the technical challenges of drilling were systematically investigated，and two technical routes for ROP enhancement were proposed，namely the optimized casing program and high-efficiency rock breaking with high weight on bit （WOB）. The proposed technologies were applied to six horizontal wells drilled in 2025 and delivered remarkable ROP enhancement performance. Specifically，based on characterization of the four pressure profiles （pore pressure，breakdown pressure，collapse pressure，and leak-off pressure），the surface casing set depth was optimized to precisely isolate low-pressure and fluid-loss-prone zones. A combined borehole profile and a potassium-calcium-based polyamine organic salt drilling fluid system were adopted to maintain a borehole enlargement ratio within 5%. Rock mechanics tests determined that efficient rock breaking in the Fengcheng Formation requires a WOB greater than 111.1 kN. A differentiated polycrystalline diamond compact （PDC） bit matching technology based on high WOB and an optimization technology for Ф139.7 mm high-stiffness bottom hole assembly （BHA） were developed to perform layer-specific optimization of drill bit parameters and operational parameters. Laboratory analyses and field applications demonstrated that this technology package can effectively resolve the ROP improvement challenges of the Mahu Fengcheng Formation shale oil and provide technical support and references for the efficient development of deep and ultra-deep hydrocarbon resources.

Drilling a horizontal well with ultra-long horizontal section in conglomerate reservoir of Mahu Oilfield in Xinjiang is faced with a series of potential problems，including large drilling torque，difficult-to-control well trajectory，low ROP，weak wellbore stability and difficulty in running in completion casing. Systematic drilling and completion technology for horizontal wells with ultra-long horizontal sections in conglomerate reservoir of Mahu oilfield has been developed by means of casing program optimization，trajectory design and control，selection of featured PDC bit，high-performance oil-based drilling fluid，R&D of toughness cement，and safe casing running technique. This technology was applied to the drilling operation of Well Mahu029_H in Mahu15 Well Block，and achieved successful drilling of a horizontal section as long as 3 038 m，smooth running of casing，and satisfactory cementing quality that meets the requirements of large SRV fracturing. A new record has been created for the longest horizontal section in Mahu Oilfield，which accumulated experience for future drilling operations of horizontal wells with ultra-long horizontal sections in Mahu Oilfield，and provided references for the same type of wells in other areas of China.