A novel application for pressure transient analysis aimed to identify the characteristic pressure response of fault reactivation in a compartmentalized reservoir, where fluid injection/extraction creates a pressure differential across the fault that leads to fault-seal breach, is presented. The analytical solution to two producer wells separated by a sealing segmenting fault is presented. Fault reactivation is incorporated into the model as a fault transmissibility enhancement occurring at the onset of fault reactivation (ts) while pressure distribution at t = ts is used as the initial condition for modeling pressure response after fault-seal breach. The single-well fault slip model is extended to the case of two wells by applying the principle of superposition. The Fourier-Laplace transform is implemented to find the analytical solution to the governing equations before and after fault-seal breach. Asymptotic solutions for early and late-time behavior are discussed too. Pressure and pressure derivative diagnostic plots are presented for various onset times and enhanced fault transmissibilities. In summary, the proposed pressure transient analysis is suitable to 1) diagnose the loss of sealing capability in a segmented reservoir, 2) estimate the threshold conditions that led to fault reactivation, and 3) characterize fault transmissibility before and after fault reactivation.

Keywords:
pressure distribution, pressure differential, fault reactivation, reservoir, transmissibility, enhanced fault transmissibility, onset, drillstem testing, fault-seal breach, compartmentalized reservoir
Subjects:
Formation Evaluation & Management, Drillstem/well testing
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2017. Offshore Technology Conference
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