As I mentioned last week, Michigan has a bunch of natural gas storage fields and one of them (that is currently being decommissioned) touches the Northeast Corner of Washtenaw County. An active field is just north of the county in South Lyon.
By a “bunch”, I literally mean Michigan has the most natural gas storage of any State in the Union as shown by the below figure. It has the most depleted field storage and the greatest amount of storage from all three storage field types.
Figure 6. 2012 State-level natural gas storage capacity from :
“Ensuring Safe and Reliable Underground Natural Gas Storage” October, 2016. Released by the United States Dept. of Energy and found here: LINK
And much of SE Michigan lives within a few Kilometers of such storage fields:
Figure 5 (from above source). Population centers within 5 kilometers of an active natural gas storage well
I haven’t been able to find a description of the Northville Storage facility, but Consumers Energy provided the below information on the geology of the Lyon 29 Gas Field from their petition to the Michigan Public Service Commission requesting construction of the well (http://www.dleg.state.mi.us/mpsc/orders/gas/2002/u-13322.pdf) :
“The Lyon 29 Field is a Silurian age Salina-Niagaran reef set in the Michigan Basin at a depth between 2,300 to 2,650 feet subsea [sic] and is located immediately south of the town of South Lyon in the southwest corner of Oakland County in a near ideal location to Consumers market. The Lyon 29 Field covers approximately 48.5 acres from the base of the reef. The Salina A-2 Anhydrite overlies the reef and is the caprock with a thickness of 27 feet over the reef, which effectively confines the gas within the reservoir. The A-2 Anhydrite Formation is very dense and non-permeable to natural gas. Consumers Energy and Staff agree that the strata involved will be from the top of the Bass Island G roup (1780 feet), the Salina Group, and the Niagaran Series to the top of the Clinton Shale (3730 feet). The storage field boundary encloses approximately 237 acres and includes parts of Sections 28,29,32, and 33 of Lyon Township (TlN-R7E), as reflected on the map attached as Attachment 1. The storage field boundary extends beyond the reef outline by nearly 1320 feet on its east side, nearly 1000 feet on the north and south sides, and 400 feet at its closest point on the west ‘side as derived from the seismic data outline of the base of the reef”
The reefs Consumers is talking about are massive deposits of ancient coral reefs. Michigan State University has a great website here describing them found here http://geo.msu.edu/extra/geogmich/pinnacle-reefs.html . I love the photos on Page Two of that website showing excavations through a reef. These reefs serve as the trap rock where oil and natural gas were originally found and now serve the purpose of storing natural gas.
Reefs, and pinnacle reefs in particular we actively sought out during the days of active hydrocarbon exploration in Michigan and likewise correlate with areas of natural gas storage. This is especially true in Southeast Michigan.
Oil/Gas fields and natural gas storage fields in SE Michigan (Storage fields are red outline, Oil/Gas fields are solid red) – from Geowebface