Modeling a Multi-Parameter Interaction of Geophysical Controls for Production Optimization in Gas Shale Systems

Area of Science:

• Petroleum Engineering
• Geoscience
• Reservoir Engineering

Background:

• Unconventional gas systems, particularly shale gas, face challenges in development due to significant stress sensitivity affecting well performance.
• Existing production models often lack detailed stress sensitivity mechanisms, relying on empirical equations for net pore stress.
• Geophysical control analysis for optimization typically uses limited local sensitivity analysis, necessitating validation for multi-parameter interactions.

Purpose of the Study:

• To clarify the influence mechanisms of stress sensitivity in gas shale reservoirs.
• To develop an integrated workflow for optimizing gas well production systems by incorporating advanced modeling and analysis techniques.
• To establish a mathematical model quantifying multi-geophysical controls on enhanced oil recovery (EOR) in shale gas reservoirs.

Main Methods:

• Development of a compound flow model for shale gas reservoirs that integrates multiple stress sensitivity mechanisms.
• Application of an orthogonal design approach combined with the response surface method for optimization analysis.
• Conducting local sensitivity analysis to evaluate the impact of various factors on long-term gas well production under different bottomhole pressure strategies.

Main Results:

• The compound flow model provides a theoretical basis for simulating production optimization in shale gas reservoirs.
• Simulation results indicate that managed pressure drawdown is suitable for high-pressure, tight matrix reservoirs, while high-pressure drawdown benefits fractured reservoirs with high water content.
• An optimization mathematical model was established, quantifying the effects of matrix properties, fracture properties, and production system parameters on enhanced ultimate recovery (EUR).

Conclusions:

• The proposed workflow offers a rational approach to optimize gas well production systems in unconventional reservoirs.
• The findings provide a more reliable reference for optimizing production systems to improve long-term recovery from shale gas reservoirs.
• Understanding and quantifying multi-geophysical controls are crucial for effective shale gas development strategies.