Modeling MDT Tester Stresses Guides Barnett Shale Fracturing to Prevent Water Production

Fracture growth into water-bearing Ellenburger

The Ellenburger carbonate formation underlying the Barnett Shale can be water bearing and permeable. Consequently, Barnett wells often produce water from the Ellenburger after stimulation. To minimize water production, an operator needed an accurate in situ stress profile across the Barnett and the bounding formations to model fracture geometry and growth potential.

Multiple stress measurements on one trip

The MDT modular formation dynamics tester tool injects fluid to create hydraulic fractures in the wellbore vicinity within an interval isolated between the inflatable elements of the Dual-Packer Module. The small, controlled injection volumes are ideal for targeting thin shale zones for evaluation. The pressure decline is monitored to determine the fracture closure pressure, which represents the minimum in situ stress. The fracture and measure procedure can be repeated many times on a single trip for multiple intervals in the well to provide a wealth of information.

Continuous stress profile and modeled fracture geometry

The MDT tester measurements of closure stress from the multiple tested intervals were used to calibrate a continuous stress profile derived from sonic logs. The continuous stress profile was input to a hydraulic fracturing simulator to confidently predict the fracture height growth and the potential for Ellenburger water production.