Stratigraphic and Depositional Framework of the Greasy Ridge Oil Field, Southern Ohio
Ronald L. Martino
Marshall University, Huntington, WV, [email protected]
The Greasy Ridge Oil Field in northern Lawrence County was discovered in 1985 and currently has 81 wells in an area of about 3.2 km². The discovery well produced 11,755 bbls of oil in 5 years from a 1.5 m thick Pennsylvanian-age sandstone at a depth of 173 m. It was estimated to have 3,040,000 bbls of in place oil, with about 10 % recoverable by primary methods. Water-flooding was implemented in the early 1990s and has been highly successful. From 1985-2010, the field produced 810,148 bbls.
An integrated stratigraphic and sedimentologic analysis was conducted in southeast Ohio and northeast Kentucky using cores, outcrops, and geophysical well logs in order to better understand the origin and distribution of reservoir sandstone. In the Greasy Ridge Field, the top of the pay sand lies about 27 m above the top of the Sharon (Maxton) Sandstone; it is clearly not the Cow Run Sand (as it was originally permitted) which occurs about 173 m higher in the Conemaugh Group. Analogues were evaluated from strata above the Sharon (=Corbin) Sandstone from outcrops located 40-50 km from the oil field near Jackson, Ohio and Greenup Kentucky. Three types of channel facies are developed: cross-laminated sandstone, heterolithic sandstone and shale, and bioturbated sandstone. Channel-fills range from 1.5-9.1 m thick. Paleocurrent patterns from cross-lamination and current ripple bedding are unimodal (SW, W) and bipolar (SW-NE). Clay-draped foresets, lenticular to flaser bedding, and shallow to marginal marine trace fossils indicate tidal influence.
Isopach maps of the Sharon Sandstone and underlying Maxville Limestone indicate that Sharon Sandstone has infilled paleovalley which underlies the Greasy Ridge Field and extends SW into Kentucky east of Ironton. The Sharon is overlain by two shale-to-sandstone parasequences 10-15 m thick containing shallow to marginal marine trace fossils (ex. Teichichnus and Lingula). The sandstone capping the lower parasequence is thoroughly bioturbated and generally has limited porosity. The sandstone capping the upper parasequence is the main producing sand, averaging 4.9 m and ranging from 0.6-9.1 m thick. Component facies consist of cross-laminated channel sands, heterolithic channel sands, and sand flats which accumulated as part of a prograding tidal flat complex. The pay sand is overlain by a seat earth interpreted as an interfluvial sequence boundary. Both parasequences are truncated by a 30 m thick, incised valley-fill sandstone that merges with the underlying Sharon Sandstone SW of the Greasy Ridge Field.
AAPG Search and Discovery Article #90154©2012 AAPG Eastern Section Meeting, Cleveland, Ohio, 22-26 September 2012