Nitrogen Foam Fracturing in the Oil Window of the San Juan Basin: A Multi- Disciplined Approach Contributes to Significant Well Results

Abstract

AbstractThe operator has successfully drilled and completed more than fifty horizontal oil wells in the subnormally pressured Gallup Sandstone (Mancos Formation) within the San Juan Basin, New Mexico. All the wells were fracture stimulated using 70% quality Nitrogen (N2) foam with 20/40 sand. N2 fracs are uncommon in modern completions but provide numerous benefits for operations in the San Juan Basin. Benefits of N2 foam fracs include reduced water usage, less proppant settling (improved carrying capacity of proppant), and less parent/child interference. The N2 fluid is high-viscosity and promotes higher height/length growth with improved fracture width relative to low viscosity completion fluids. These properties of N2 foam fluids help prevent damage to parent wells and result in an ideal fracture geometry.This paper discusses methodologies employed by the operator resulting in significant improvements to well results. Methods include a) fracture design/modeling optimization with N2, b) parent and child well management, c) strategies for mitigating fracture-driven interactions, and d) a presentation of well results. The paper compares the completion parameters used in newly drilled wells versus legacy wells and contemporary offset completions to provide context to well results. Additionally, pressure management is utilized during flowback and production of both parent and child wells, resulting in improvements in oil productivity, load recovery, and minimal proppant returns during flowback. Pressure management incorporates both wellhead choke management and gas injection volume management as methods to maintain reservoir pressure in the short and long term.The combination of N2 foam hydraulic fracs, pressure management during flowback, and production optimization has led to significant improvements in horizontal Gallup sandstone well production. Incremental improvements have been made to all aspects of the completion, flowback, and production processes. Nitrogen foam fracturing is an understudied completion design that has had limited deployment in oil reservoirs across the oil industry. Strong production results from Gallup Sandstone N2 completions suggest that the technology is worth further consideration and study. This methodology could provide insights for other operators with similar reservoir conditions.