Interest in re-stimulation of unconventional horizontal wells has continuously grown as operators and service companies recognize the existing opportunities to improve well productivity and recovery through refracturing operations. In response to this interest and to address the many challenges associated with this type of treatment, five operators in the Eagle Ford and one service company joined efforts in a Refracturing Consortium. Accelerating the learning while identifying the drivers for re-stimulation economic success were the main goals of the consortium
The project focused on testing various re-frac designs around recently developed diversion techniques to determine the best refracturing practices. A systematic candidate evaluation and re-stimulation design workflow was developed. Real-time monitoring was used to facilitate appropriate design modifications. Comprehensive evaluation was performed to determine the success factors.
Refracturing treatments were performed on 11 wells located across the field with varying completion and production characteristics. The production results are encouraging: uplifted production was attained from the majority of these wells and for a good number of treatments the increased production has been sustained over time. Incremental production six months after the treatments has averaged 25 Mbbls above what was expected in these wells without intervention.
This paper presents the production results from the campaign and discusses the success factors and main lessons learned such as:
Production uplift can be achieved with refracturing and it can be sustained over time
Candidate selection/recognition is a key factor for the design and success of a re-frac job
Treatment design should target early diversion that enables pumping the job within the original completion ISIP range
Refracturing the entire lateral is a major challenge
Viscous fiber laden fluids can improve proppant suspension thus re-frac lateral coverage
Tight infill pads risk detrimental interference between wells for larger refracturing treatments. In this scenario, considering the wells as a single system is preferable
Refracturing a "parent well" prevented detrimental frac hits and enhanced performance on both parent and "child wells"
The value of adding perforations is uncertain
Pre and post re-frac well measurements and modeling are critical for proper evaluation of re-frac effectiveness and modify strategy for future wells in similar environments