Shale Gas Horizontal Well Drilling Technology

Shale Gas Horizontal Well Drilling Technology

The core of shale gas development lies in maximizing the exposed reservoir area and releasing natural gas resources from low-permeability shale through horizontal well technology. Its technological integration focuses on two main aspects: safe and efficient drilling of long horizontal sections and efficient well completion aimed at achieving large-scale volumetric stimulation. The synergy of these two aspects determines the final productivity and economic benefits of a single well.

Long horizontal section drilling technology aims to achieve high-quality, rapid, and economical horizontal section extension. Key technologies include:

"Well Factory" batch operation mode: Deploying multiple wells in the same well site, and using standardized equipment and processes to achieve efficient turnover of drilling rigs, personnel, and materials, significantly reducing non-productive time and single-well costs.

Deep integration of rotary steering and geological steering: Employing a high-build-rate rotary steering system to achieve precise and smooth trajectory control, ensuring that long horizontal sections "traverse" thin reservoirs. Combining geological steering technologies such as gamma-ray while drilling, resistivity, and azimuth imaging, real-time identification of lithological changes, microfractures, and formation interfaces is used to dynamically adjust the trajectory, ensuring that the wellbore always remains within the "sweet spot" zone.

High-performance water-based drilling fluid system: To address the challenges of high frictional torque and demanding wellbore stability requirements in long horizontal drilling sections, environmentally friendly water-based drilling fluids with strong inhibition, strong plugging, and high lubricity are widely used to replace traditional oil-based drilling fluids, reducing environmental risks and costs while ensuring performance.

Integrated high-speed drilling technology: Through personalized PDC drill bit design, drag-reducing and speed-up tools such as hydraulic oscillators/torque impactors, and real-time optimization of drilling parameters, technical bottlenecks such as slow mechanical drilling speed and severe pressure build-up in long horizontal sections are overcome, achieving efficient drilling.

The goal of integrated efficient completion technology is to create optimal conditions for subsequent fracturing and achieve effective stimulation of each section. Core technologies include:

"One-trip drilling" bridge plug perforation operation: Using a drillable composite bridge plug connected in series with a multi-cluster perforation gun, it is run in a single trip via cable or coiled tubing to achieve simultaneous setting, perforation, and release operations, opening the casing in clusters and creating an independent entry point for each fracturing section. This process is highly efficient and is currently the main technology.

**Multi-cluster dense-cut perforation technology:** Increasing the number of perforation clusters within a single section (e.g., to 8-12 clusters), shortening the cluster spacing, and coordinating with fracturing processes promotes the formation of complex fracture networks, increasing the stimulated volume.

**Casing cementing quality assurance:** Long horizontal sections place extremely high demands on casing centering and cement slurry displacement efficiency. This necessitates the use of elastic cement slurry systems, optimized rigid centralizer placement, and rotating casing running technology to ensure annular sealing quality, providing a reliable barrier for staged fracturing.

**Integrated fracturing and completion design:** Completion plans and fracturing designs are coordinated beforehand. Based on differences in geological engineering "sweet spots," the location of each segment and cluster, perforation parameters, and bridge plug positions are optimized to achieve precise "one-section-one-policy" stimulation.

The close integration of long horizontal drilling and efficient completion forms the technological cornerstone of efficient shale gas development. Through the dual-drive of improved drilling efficiency and cost reduction, and improved completion quality and capacity, the final recoverable reserves of a single well are continuously increased, propelling the shale gas industry towards a new stage of large-scale and efficient development. Future technologies will continue to evolve towards ultra-long horizontal sections (>3000 meters), fully electric automated drilling, intelligent fracturing, and dynamic production optimization.