All wells do not have data. 
     Wells that have a well type of LOC (location) or a status of TP (terminated permit) or PW (permitted well) have not been drilled or if drilled, the permittee hasn't reported the data to OGS yet. Older wells may have data in paper files that has not been entered into the OGS well database.

          Explanation of Data
     The Formation Tops & Elevations Download consists of a Microsoft Access database containing the following five tables: Elevations, Formation codes, FormationTops, Method Obtained, and Reference point codes.

In the Elevations table, Column 1, Location_ID is the well API number. Elev_Gr is the elevation of the ground surface at the well, Elev_KB is the drilling rig's kelly bushing elevation, Elev_DF is the elevation of the drilling rig (or derrick) floor.  Column 5, Ref_Tops, gives a code identifying which elevation was used as the reference elevation in picking the formation tops for the well identified by the API number.

The Reference point codes table lists Definitions for codes used in the Ref_Tops column in the Elevations table.

The Formation codes table contains American Association of Petroleum Geologists codes (AAPG_Cd) for Michigan rock formations and the full name of the formation. The OGS publication, "Stratigraphic Lexicon for Michigan" and its companion chart "Stratigraphic Nomenclature for Michigan" provide an extensive compilation of stratigraphic terms.

The Method Obtained table lists Definitions for the various sources of formation top data.

The FormationTops table lists formation top information by API number. The table can be sorted, filtered, or queried by various factors utilizing Microsoft Access tools. For example:  Using a well's API number, the formation tops for that one well can be listed together.

Other downloads "Locations - Oil & Gas wells - download database" and "Production of Oil and Gas wells - download" are available and can be used in conjunction with the Formation Tops & Elevations download for advanced stratigraphic and/or production investigations.

 The following download is a zipped Microsoft Access database last updated 9/4/2008. The zipped file size is approximately 7.1 MB. Unzipped the database is approximately 44 MB.
Download Formation Tops.

If you do not have Microsoft Access, you can use the OGS Online database. Formation top data is located under the 'Well Information' tab, then under the 'Well Formations' tab.