Film for well logging

I had an interesting conversation with a friend today who used to work in the oil fields. He said that they used to use film to log the wells they drilled. The film was black and white, about 12-inches wide and 140-feet long. As the drill went through the earth it would create some kind of electrical impulse that would expose the film. He said they would take the film into a trailer that was their darkroom where they’d unroll it through developer and then the fixer. Somehow it got dried along the way. Then the developed film was sent through what sounds like a ammonia-based blueprint (white line) machine to make hard copies for the client on fanfold paper.

Is anyone familiar with that process? I wonder about the film they used and if any is still laying around.

Not heard of this. Did he say where the electrical impulses came from such as the drilling machine and how it was transmitted to form light on the film? Thanks

pentaxuser

I worked for a company 5 decades ago, which made equipment for turning paper well log strips into digital data. But I had never heard of photographic recording of well logs. In fact the equipment to digitize well logs had largely gone out of use by the mid-1970s...I was never asked to make presentation to any customers in that industry!
There is little information on the web pertaining to photographic well logs, other than the fact the technique of photographic recording was invented in 1935. I found reference to the use of 135 film or microfilm to record.

I located a document published in 1984 which makes a large number of references to using film to regard galvanometer recordings, but there is no mention of film type involved, and by then much of the recording had moved to magnetic tape recording rather than photographic.

"These can take the form of a film, which records galvanometer readings under suitable calibration conditions, or of a tabular summary in the case of Schlumberger Cyber Service Unit (CSU). "

pentaxuser said:

Not heard of this. Did he say where the electrical impulses came from such as the drilling machine and how it was transmitted to form light on the film? Thanks

pentaxuser

Click to expand...

Some background...
https://www.rigzone.com/training/insight.asp?insight_id=298&c_id=

pentaxuser said:

Not heard of this. Did he say where the electrical impulses came from such as the drilling machine and how it was transmitted to form light on the film? Thanks

pentaxuser

Click to expand...

He didn’t give me that much detail but he probably could. Later in his life he was a professor of physics. Today he rebuilds engines for MGs, Triumphs, Healys, etc.

I had to dig around a bit - my geological training was not in drilling/down-hole geophysics. https://patents.google.com/patent/US2996619A/en
This is a patent for using photographic film in gamma ray recording down-hole. These days it is done using electronically using scintillation detectors. The gamma radiation is naturally occurring, and varies with the age and mineralogy of the rocks. Pulling a core from depth is expensive (pull the string of drill pipe, substitute a coring bit, put the string back down the hole, and cut the core. Then do the whole process over again to put the regular bit back in the hole.), so anything that can indicate strata relationships is useful. The cuttings that come up with the drilling mud are a very coarse guide to the geology as they get mixed up in transit back to the surface.

There is a USGS introduction page at https://www.usgs.gov/mission-areas/...ce_center_objects=0#qt-science_center_objects
for anyone curious to look further.