Single- and Cross-well Flow Analysis for Flowpath Characterization in a Fractured Mudstone

Single- and cross-well flow analysis was used to characterize fracture zones and flowpaths in a mudstone within the Newark Basin of northeastern United States as the preliminary part of a bioaugmentation research study. Flow logs were analyzed from a shallow recovery well, a deep monitoring well scheduled for bioaugmentation injection, and three test wells installed along the dip direction to determine potential flowpaths between the recovery well and the monitoring well. Flow logs collected under quasi-steady-state ambient and single-well pumped conditions were analyzed to estimate fractured-zone transmissivity and hydraulic head. Flow logs collected under transient cross-well pumped conditions were analyzed to determine fracture-zone connections. Integrated analysis of the flow logs with gamma, image, and core logs indicates that most of the transmissive fracture zones occur in thin beds of laminated and carboniferous mudstone, which are cyclically interbedded with more massive mudstone units. Estimates of transmissivity and hydraulic head of the fracture zones based on single-well flow analysis were consistent with values from hydraulic tests and water levels measured in discrete intervals isolated with straddle packers. Fracture-zone connections determined from the cross-well flow analysis were consistent with the dip of the transmissive beds.