Seismicity Induced by Hydraulic Fracturing in Ohio in 2016: Case Study of the Conotton Sequence in Harrison County

Date: 4/26/2019

Time: 06:00 PM

Room: Fifth Avenue

In November of 2016, a sequence of hydraulic fracturing induced seismicity was observed in Harrison County, Ohio. The events in this sequence were ≤ M 2.7 and were spatiotemporally correlated with hydraulic pumping stages from the Conotton horizontal wells. A series of adjacent wells to the west of the Conotton wells also induced seismicity along an east-west trending basement fault system. The fault’s east-west trend extended beneath the Conotton horizontals based on seismicity observed in 2015, and the seismicity from the Conotton stimulation is an extension of the same fault system. Using a 5 station seismic network, 129 earthquakes were picked and located using Hypoinverse. Relative locations were obtained using HypoDD and demonstrate that the activity was 800 to 1200 meters below the Utica formation being stimulated and related to the crystalline basement fault system. In addition, cross-correlation template matching techniques were used to observe some ~1200 detections of earthquakes with M > -0.85. Interestingly, the b-value evolved from values > 1 early in the sequence to < 1 when the larger events started happening. During the sequence, the operator took mitigation actions by skipping stages and reduced volume across stages that were closer to the fault. Pressure and volume data were investigated to assess if there was any relationship with specific stimulation parameters to the earthquake rate. Production data from the wells are also examined to investigate how interactions with a fault influence produced oil, gas, and brine.

Presenting Author: Paul Friberg

Authors