Physical Log Category—Log Types and Codes

Log Type   

Log Code

Explanation

Colored Drillers Log

CDL

For many older Indiana wells, Colored Drillers Logs were prepared using the brief sample descriptions contained on the Driller’s Log. These are sample descriptions portrayed using a simple color-code to represent lithologies portrayed on a 1 inch = 100 feet cardboard strip. Colored Drillers Logs were prepared at the IGS until the mid-1960s when the practice was discontinued because geophysical logging was becoming common and because rotary drilling was replacing cable-tool drilling. The sample cuttings retrieved in rotary-drilled holes may be less reliably identified and recorded by the drilling crew.

Core

Actual cored rock obtained from a well. Although Cores are entered separately into the PDMS in the Cores Subtable, they are entered as Physical Logs in the Log Info Subtable in cases where they are used as a source for Strat Picks.

Driller’s Log

DRL

As used by the petroleum industry, Driller’s Log refers to a brief record of information about the hole recorded by the driller or his crew as the well is drilled. The driller, who is not necessarily well trained in describing samples, often includes cursory descriptions of the samples retrieved at certain depths, and the occurrence of geological formations. Quality is quite variable and tops taken from a Driller’s Log should be considered with a skeptical eye. Note: In times past, when petroleum well records at the IGS were indexed in an elaborate card system, the term Drillers Log was used to refer to the well’s Completion Report which was submitted to the state by the operator of a well. This practice has been discontinued and the PDMS terminology now conforms with that of industry.

Drill-Time Log

DLTM

A graphical log that plots the drill-time per foot in relation to the depth of the hole.

Graphic Log

GRPH

Logs which display sample descriptions in a vertical log format that uses graphic symbols to display lithology [excluding Colored Drillers Logs and Mud Logs]. Historically, the IGS also used the term Graphic Log to refer to logs known in the industry as Mud Logs. Although the term Mud Log is now only used for "true" Mud Logs, some older logs in the PDMS which are identified as Graphic Logs should properly be called Mud Logs.

Lithologic Strip Log

Sample cuttings of a well which have been glued onto 5 inch = 100 feet cardboard strips by the IGS. Although Lithologic Strips are entered separately into the PDMS in the Samples Subtable, they are entered as logs in the Log Info Subtable in cases where they are used as a source for Strat Picks.

Mud Log

MUD

In industry parlance, a Mud Log is an analysis of the drilling mud and well cuttings for signs of hydrocarbons that is conducted as the well is drilling. Until recently, the Indiana Geological Survey has used the term Graphic Log to refer to Mud Logs and other types of logs which display sample descriptions in a vertical log format using graphic symbols to represent lithology. Although the term Mud Log is now only used for "true" Mud Logs, some older logs in the PDMS which are identified as Graphic Logs, should properly be called Mud Logs.

Other Physical Log

OPHL

A physical log that does not otherwise fall in another designated Physical Log category.

RFT (Repeat Formation Test) Log

RFT

An RFT log records formation pressure data (and obtains a small rock sample) of the formation.

"see '-----'

Any value in the Physical Log Type data field that begins "see '-----', is not an actual geophysical log. Instead, it is place holder that references a particular report in the Reports Subtable. There is no database connection in the PDMS that links a specific report in the Reports Subtable to its associated partner in the LogInfo Subtable.

The "see -----" value is a "faux log" entry in the Log Info Subtable that allows calculations to performed as if they were associated with actual log data in the PDMS. For example, if no logs are available, a Strat Pick value can be obtained from a Completion Report, and entered as a data value in a "see Completion Report" value in the LogInfo Subtable, were it will be processed  as any other Strat Pick value to determine its subsea altitude.

see Completion Report

see above

see Core Analysis

see above

see Core Description

see above

see Geological Report

see above

see Letter

see above

see Plugging Report

see above

see Rework Report

see above

see Sample Description

see above

see Sample Report

see above

see Sample Study

see above

see Scout Report

see above

see Scout Ticket

see above

see Survey Well Record

see above

see TVD Report

see above

Samples

Actual sample cuttings from a well. Although sample cuttings are entered separately into the PDMS in the Samples Subtable, they are entered as logs in cases where they are used as a source for Strat Picks.