Study on Pressure-Bearing Patterns of Gel Plugging Agents in Multi-Scale Fractures

Area of Science:

• Petroleum Engineering
• Reservoir Engineering
• Materials Science

Background:

• Fractured reservoirs face challenges with water channeling and residual oil in multi-scale fractures.
• Conventional plugging agents show ambiguous pressure-bearing patterns, leading to low oil recovery and efficiency.
• Understanding gel strength in multi-scale fractures is crucial for effective reservoir development.

Purpose of the Study:

• To investigate the gelation performance of temperature-resistant gels (TRGs) with varying elastic moduli.
• To establish a quantitative and normalized evaluation method for TRGs in fractured reservoirs.
• To correlate TRG elastic modulus with fracture scale and plugging performance for improved field application.

Main Methods:

• Investigated gelation performances of TRGs with different elastic moduli, normalized by elastic (G') and viscosity (G″) moduli.
• Researched bottom water pressure patterns of TRGs in multi-scale fractures.
• Developed an influence pattern chart and fitted an optimal surface function using MATLAB for quantitative evaluation.

Main Results:

• A TRG with an elastic modulus of 19.42 Pa effectively plugged fractures, remaining stable for over 90 days and improving oil recovery by 58.7%.
• A TRG with an elastic modulus of 14.29 Pa showed inefficient plugging and only a 15.2% oil recovery enhancement.
• Established a quantitative evaluation method and a characteristic chart correlating elastic modulus with plugging performance.

Conclusions:

• The study provides practical design criteria for selecting TRGs based on elastic modulus for fractured reservoirs.
• The developed method bridges the gap between laboratory gel evaluation and field application.
• Optimized TRG selection enhances efficiency and adaptability of gel plugging strategies in harsh reservoir conditions.