The Austin Chalk play arches across South Texas and sits directly above the prolific Eagle Ford formation, which serves as its source reservoir. As with many unconventional resources, the Austin chalk has experienced an evolution of drilling and completion strategies since the initial development of the formation with vertical wells. Operators active in this South Texas formation turned their focus to drilling horizontal laterals into the reservoir from both existing and new wells to capitalize on the natural fractures within this low porosity, carbonate formation.
During drilling and completions issues can arise in soft rock formations, such as hole-washout, stabilization and hole-quality. These issues lead to poor isolation and result in lower production than expected. An operator in the Austin Chalk formation preferred to continue using open hole technology to take advantage of the natural fractures but needed to improve stage isolation to remedy the issues mentioned above.
Packers Plus designed a completion solution for four candidate wells, using SoftSEAL® II packers. The dual-element high expansion packers were specially designed for oversized and elliptical wellbore to minimize the risks of completing a well in a soft rock formation.
Packers Plus installed the four 13-stage wells within six months in the Texas counties of Frio and Atacosa. Designed using StackFRAC® HD completion technology, all systems were run into the wellbore to a measured depth range of 17,162 to 18,942 ft. Lateral lengths ranged from 5,038 to 6,938 ft, with an average stage spacing ranging between 350 to 432 ft.
All wells were successfully stimulated within two weeks following the installation and in an effort to minimize formation damage; stimulation was conducted with a water based mud.
The four wells using Packers Plus SoftSEAL II technology were some of the best producing wells in the area. When compared with 17 offset wells in the two counties the operator was targeting, Packers Plus had the highest producing well for the first 12 months of production. Average production of the Packers Plus wells was 66% higher than the average production of the offset wells for the first 12 months of production.
The operational success of these wells reflects the capability of Packers Plus innovative technology and services for challenging completions in the Austin Chalk and similar soft rock formations.