Utica shale is one of the major source rocks in Ohio and extends across much of eastern US. Its organic richness, high content of calcite, and development of extensive organic porosity makes it a perfect unconventional play and has gained the attention of the oil and gas industry. The primary target zone in the Utica includes Utica, Point Pleasant, and Trenton intervals. In the present study, we attempt to identify the sweet-spots within the Point-Pleasant interval using 3D seismic data, available well data, and other relevant data. This has been done by way of organic richness and brittleness estimation in the rock intervals. The organic richness is determined through TOC content which is derived by transforming the inverted density volume. The core-log petrophysical modeling provides the necessary relationship for doing so. The brittleness is first derived using rock-physics parameters such as Young's modulus and Poisson's ratio, and considering the importance of mineralogical information, we derive brittleness from this information as well. Deterministic simultaneous inversion along with a neural network approach are followed in order to compute rock-physics parameters and density using seismic data. The consistency of sweet spots identified based on the seismic data with the available production data emphasize the integration of seismic data with all other relevant data.
The Utica shale is considered a source rock for oil and natural gas, which migrated upwards and were produced by conventional means in the overlying rock formations. According to a 2012 USGS report, the formation holds 940 million barrels of oil and approximately 38 tcf of natural gas (Kirschbaum et al., 2012), but with more drilling and production, these estimates have been revised and stand at 2 billion barrels of oil and 782 tcf of natural gas (Cocklin, 2015). The thermal maturity studies in the Utica shale have indicated a northeast to southwest trend over eastern Ohio and western Pennsylvania, with a western oil phase window, a central wet gas phase window and an eastern dry gas phase window.
