The Utica-Point Pleasant shale reservoir, an organic rich middle to late Ordovician deposit in eastern Ohio, is one of the more recent unconventional reservoirs to be appraised for development. Similar to other shale plays, the Utica-Point Pleasant formation presents formidable challenges for characterization and exploitation due to its high degree of reservoir heterogeneity and the presence of a wide range of hydrocarbon fluids from dry gas to retrograde condensate and oil.
This paper presents a case study covering the implementation of a well pad specific, holistic, data gathering and evaluation program aimed at improving the understanding of reservoir and in situ fluid properties, completion effectiveness, well productivity, EUR, and well interference in order to define optimum well spacing for further development.
Four horizontal wells were drilled parallel to one another in the rich wet gas area of Utica play. A 10' long pressure core was acquired in the target interval in order to acquire a down-hole fluid sample for comparison with separator and well head samples. The analyses of the liberated gases and extracted liquids from the core provide an alternative and faster way to determine in situ fluid properties in addition to obtaining more reliable saturations and basic core properties. A series of logs were run in a pilot hole to assist in the placement of the well laterals in the target interval. Chemical tracer tests were conducted to understand the efficiency of inflow for each of the fracture stages, and down-hole micro-seismic mapping in three wells was used to evaluate the fracture geometries. Integration of this extensive data set will offer significant insights into future well performance, recovery, and well to well connectivity in this area of the play. The acquisition of a pressure core was particularly critical to understand any variation in fluid composition and properties down-hole compared to surface samples since condensate recovery is one of the major uncertainties impacting project economics. A discussion of the pressure core analysis, and other lessons learned on completion efficiencies and well interference and spacing will be presented.
