Seismic Evaluation of the Trenton/Black River Napoleon Field, Jackson Co., MI.
The Napoleon Field is a fractured hydrothermal dolomite reservoir developed in the Trenton/Black River formations in southeastern Jackson County, MI. The field was discovered by West Bay Exploration Company and its partners in 2008 using proprietary 2D seismic. The majority of the 2D seismic was acquired using a vibrator source with an emphasis on obtaining high frequency and high signal-to-noise data. Seismic data collected over the Albion-Scipio Field, also a fractured hydrothermal dolomite reservoir; was used as an analog in the search for similar anomalies. Placement of the regional 2D seismic program was based on proximity to known production in areas that had both limited drilling and were under-explored seismically in the past. Due to the generally restricted nature of fractured hydrothermal dolomite reservoirs in Michigan as well as their limited structural expression, well control was not a reliable indicator of reservoir proximity.
The approximate extent of the Napoleon Field was first defined using a coarse grid of 2D seismic. The 2D anomalies were used solely to aid in leasing and positioning of detailed 3D seismic surveys. Prior to imaging the entire field, two smaller 3Ds were conducted near the northern and southern ends of the field. Two test wells were then drilled to confirm the existence of reservoir rocks and hydrocarbons. Upon successful completion of the test wells the remainder of the field was imaged using 3D seismic. Various attributes of the 3D surveys; such as time maps, amplitudes, coherency, and others were used to map the extent and internal architecture of the reservoir. Time maps were used to map the classic Trenton ‘sag’ features which are commonly associated with fractured hydrothermal dolomite reservoirs. Amplitudes were useful for mapping deep-seated fracture trends and in certain cases were used to map high porosity zones within the Trenton/Black River interval. Coherency was useful in mapping the likelihood of fractures in the reservoir interval as well as the fracture orientation. To date, the 3D seismic data has been very reliable in locating reservoir quality rock, with some of the reservoir detail being beyond the resolution capabilities of the seismic data. The drilling results continue to be integrated with the seismic data in order to design a drilling plan to best develop the field.
AAPG Search and Discovery Article #90154©2012 AAPG Eastern Section Meeting, Cleveland, Ohio, 22-26 September 2012