On December 4, the acidizing and fracturing team of the Downhole Operations Branch of Southwest Engineering efficiently completed 39 stages of ultra-high-pressure zipper fracturing on the Leiye 1-1HF well and the Leimaoye 1HF well. The operation achieved a maximum of four fracturing stages in a single day, with an average daily efficiency of 3.11 stages, earning commendation from the project owner. This achievement has laid a solid foundation for exploration breakthroughs in the Permian marine new strata of the Puguang area in the Sichuan Basin and is of great significance for the subsequent large-scale development of deep shale gas.

The Leiye 1-1HF and Leimaoye 1HF wells are the first ultra-high-pressure zipper fracturing well cluster deployed by the Exploration Company in the Yuanba exploration area. Their core objective is to evaluate the reservoir potential of the third member of the Maokou Formation and the Dalong Formation in the Puguang area, providing technical support and regional transformation data for deep shale gas exploration and development.

Faced with challenges including tight schedules, complex geological conditions, and extremely high operating pressures, the operation team adopted an integrated single-project management model. By coordinating personnel deployment, technical support, and construction organization, and through the centralized allocation of multidisciplinary resources and rapid on-site decision-making, the team ensured safe and efficient execution.

Through overall coordination, the team accelerated the start-up schedule by 40%. By intervening early in design planning and site layout, and formulating full-process operation plans for key steps such as equipment mobilization, material allocation, and pipeline installation, critical timelines were precisely controlled. An innovative collaborative model featuring overlapping processes and shared equipment was implemented, enabling round-the-clock operations through coordinated shifts among coiled tubing, fracturing, and well testing teams. With a “one-team” approach and on-site coordination meetings to resolve cross-operation challenges, first-stage fracturing conditions were achieved in just 10 days—over 40% faster than originally planned.

To address reservoir stimulation challenges, experts tailored fracturing designs to the geological characteristics of the Permian marine new strata in the Puguang area. Drawing on experience from adjacent wells and real-time field conditions, the team selected a volumetric fracturing process combining differentiated fracture placement, medium-to-high-viscosity fluids with small particle sizes, and continuous sand addition at low sand ratios. A joint evaluation mechanism was established with the Yuanba Project Department and the Beijing Engineering Research Institute, enabling real-time optimization of parameters based on monitoring data and geological dynamics. For the thin yet high-quality shale reservoirs of the Maokou Formation and the exploration targets of the Dalong Formation, a “one-stage-one-strategy” approach was implemented to maximize stimulation effectiveness under complex geological conditions.

Each fracturing stage exceeded 2,000 cubic meters in scale, with a maximum operating pressure of 111.9 MPa. Total injected fluid volume exceeded 88,000 cubic meters, and sand volume surpassed 4,900 cubic meters, ensuring continuous and efficient operations throughout the campaign.

Fine management measures were also implemented to strengthen safety and environmental protection. Staggered operations were adopted, with daytime intervals used for inspections and maintenance, and nighttime dedicated to in-depth equipment servicing. An integrated material management system ensured precise, phased supply, safely delivering more than 550 tonnes of sand and over 7,000 cubic meters of water per day. A full-chain safety control system was established, featuring enhanced job safety analysis, intensified monitoring of neighboring wells, physical isolation and warning zones, and strict implementation of tiered confirmation and grid-based responsibility systems. Remote monitoring and unmanned management in high-pressure zones further ensured safe and environmentally compliant operations.

The successful implementation of ultra-high-pressure zipper fracturing in the Yuanba exploration area demonstrates Southwest Downhole Operations’ strong technical capabilities and integrated service strength in deep and complex gas reservoir stimulation. It not only provides critical data for evaluating the production potential of the Maokou and Dalong formations, but also advances exploration breakthroughs in the Permian marine new strata of the Puguang area, injecting strong momentum into efficient shale gas development in the Yuanba block.