Methods for analyzing surface pressure data in real time are proposed and demonstrated to improve the completion design and cluster efficiency of child wells while protecting nearby parent wells.
This study involves three parent wells and ten child wells, landed horizontally in the Wolfcamp A and B reservoirs in the Delaware Basin. An integrated real-time analysis of surface pressure measurements acquired from parent and offset child well completions enabled informed decisions regarding pump rate, fluid volume, frac stage sequence, and diverter schedule on subsequent stages. Results included the mitigation of frac-hits at the parent wells and improved fluid distribution of the child wells.
Real-time monitoring indicated significant fluid communication during treatment between child and parent wells. The order of operations and completion design were changed during the job to reduce the risk of adverse effects on both well types from frac hits. By changing the treatment design, the magnitude and characteristics of pressures observed in the parent well showed significant reduction in the intensity of fluid communication. The design change also improved cluster efficiency of the nearby child wells, with no indication of damaging frac hits occurring.
Pressure-based fracture mapping was used to supplement observations from the parent well. These pressure responses, recorded from an isolated stage on an offset well, were used to compute fracture geometries and growth rates of the stimulated fractures. The fracture height of the child wells decreased after adjusting the order of operations and completion designs during stimulation, which indicated fracture containment within the target zone. These results validated the improved cluster efficiency findings. The differences in geometries and growth curves were interpreted as improved fracture quality near the wellbore, with no damaging frac hits from the completion stages.
Real-time pressure monitoring and analysis provides immediate, accurate feedback during stimulation. Data-driven decisions enables optimization of the frac design and pump schedule (slurry rate, slurry volume, proppant volume, proppant concentration, etc). Comprehensive understanding of the fracture growth behaviors assists in making more-informed decisions during the execution of a well stimulation program, mitigates parent well damage, and enhances child well production.