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  Part Two Of the Oilfield Employment Series. Mudlogging Jobs.

How to Get a Job As a Mud Logger In the Oil and Gas Drilling Industry 


The oil and gas industry is booming and companies are hiring. The job of mud logger or mudlogger is a good way to get a foot in the door of this fast growing industry. *(Note that many large companies require a degree in geology, smaller ones may not.)

The job of the mud logger or mudlogger is to collect samples of rock cuttings that are brought up from the rig's drill bit deep underground. The cuttings and also traces of natural gas are contained in the drilling fluid or mud that has been circulated down the drill pipe, through holes in the bit and back up the open hole to the surface where goes over a mud shaker which separates the cuttings from the liquid.

The logger regularly collects a sample, which is correlated to the depth at which it was cut. He then washes the cuttings in either water or diesel, cleans the cuttings further and looks at them under a microscope and fluoroscope or ultra violet light box. He will classify them as one of several types of rock such as sand, shale, dolomite, limestone, etc and note any oil traces that are within the pores of the cuttings.

He notes these on the 'log" that is like a road map of the drilled well showing what types of rock are at what depths and reports productive zones or "shows" to the oil company geologist.

The first step is to ask yourself if you can handle a job that involves living in a travel trailer on a rig site or sleeping, (when you can) in crowded crew quarters offshore and being gone for days at a time away from home.   You will be rewarded with good compensation at then end of the month but you will be away from home for sometimes weeks at a time, unable to leave until the well is done, working in dirty, dangerous and harsh environments.  Work hours are long and often unpredictable, often in 12 hour increments or tours, pronounced "towers".

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The oilfield is booming like no other time in history and salaries are going up for most all oilfield jobs. Employers are paying salaries for mudloggers range from $50,000 per year plus daily per-diem expenses to $80,000 or more for the top end companies providing multiple logging services such as pore pressure analysis. You are usually paid by the day, from $175 plus around $35 to $70 per diem, with some companies possibly paying  a modest monthly salary in addition to the day rate.

Since you will be staying on the well site for days on end, with no real expenses and nowhere to spend your money it is a good way to save up several thousand dollars in a couple of years. I have friends who have paid off their homes this way.  Most large companies such as Sperry Sun, a division of Halliburton require college degrees in geology. This is not to say that the job of mudlogger is an entry level job since many companies only hire petroleum geologists but there are lots of small companies working on land rigs where the drilling is not as technical as offshore, that hire qualified non college graduates and train them. Although mudlogging as a profession is not considered a high status position on a well site due to the fact that they are not involved in the activities on the rig floor, a good mud logger can save the day if he is well trained by predicting a "kick" or gas bubble that is heading upwards in the drill pipe because the mud weight is not heavy enough. A "kick" can be the prelude to a blowout and many have been prevented by a good mudlogger.

Gas Monitoring

Located at the mud pit closest to the flow line bringing back  drilling mud and cuttings from underground, the logger places a motorized (air or electric motor) agitator that stirs up the drilling fluid or "mud" and releases any gas it contains. The gas is sucked back to the loggers "shack" or mobile office by a vacuum pump and  a device called a chromatograph analyzes it for it's hydrocarbon contents such as methane, propane, isobutane, etc. Another device, called a "hot wire" reads total gas and is used as a benchmark to show how much  natural gas is contained in the mud. If the logger sees an increase in the readings of these two instruments he may be encountering a "show" or zone of productive oil and gas.

Interpretation of "Shows"

With experience, a mudlogger will be able to determine zones where oil and gas may be plentiful enough to produce. Through analyzing a combination of factors such as the rock cutting porosity (ability to hold oil and gas), the amount of gas and components, drill rate, etc, and he will note on the mud log if the zone is productive.

The "mud logs" that he produces are e-mailed out and closely watched by oil company geologists who can determine if they have made a productive well or not and if they are drilling horizontally, if they need to drill in one direction or another to encounter the most oil or gas.

Monitoring for "Kicks".

An important job of the logger is to watch for  large gas bubbles that rush into the drilled wellbore and head toward the surface, potentially causing a dangerous blowout, or drilling rig disaster due to uncontrolled flow of oil and gas. One manner in which the logger does this is  if he notices increases in "connection gas" or gas that enters the well bore when the rig crew stops the pumps and adds another joint of pipe to be drilled down.   Because the overall pressure of the mud in the well column (that is holding the pressurized gas back) decreases when the pumps are off, the mud logger can get an idea if the drilling mud is getting close to being "under balanced' or not heavy enough to hold the underground pressure back. Weight may need to be added to the drilling mud by adding barite to prevent an under balanced situation.


In addition to analyzing and recording the types of rocks found in the samples the logger may be required to fill wet or dry bags of rock cuttings  from different depths to be further analyzed in a geology lab for oil and gas.

Some mobile labs have microscopes that can take a photo of the porosity, or spaces between the sand grains in the rock, and these photos can be e-mailed to the oil company geologist for inspection.



The degree of technology used in the mobile lab and the expertise required to operate it vary from type of well and company to company. Large companies such as Halliburton require that their loggers be geology graduates but smaller "mom and pop" companies working on land jobs will hire persons to train to become mudloggers with no prior oilfield experience. Typically the job is more technical and challenging offshore and in areas on land where there are unpredictable underground pressures.

What Applicants Must Have

Many companies, especially the larger ones, require all applicants to have a degree in geology. Other small companies will offer you on the job training. You will need good mechanical, computer and troubleshooting skills  to be a mudlogger. You will need to be single or have a stable home life and be able to travel and stay away from home for up to months  or more at a time with no breaks. You will need a good command of English and an ability to work and communicate well with persons from diverse backgrounds such as roughnecks and geologists. All oilfield service companies drug test so being drug free is essential to all oilfield jobs.

Living Conditions and Work Hours

The logger may or may not reside as well as work in the small "logging unit" or trailer that is situated on the drilling site. Other times companies may allow workers to stay off premises in a motel for their 12 hours off (if that is their work arrangement) if the job is on land. If it is on an offshore drilling rig then service hands such as mudloggers sleep in crew quarters with bunks, several men to a room and do their work out in a portable unit that looks like a  large walk in freezer because of the airtight and fire resistant construction. In addition to 12 hour schedules some companies provide one-man services  for the oil company at a reduced rate, where one logger will work 24 hours, day after day, napping when possible until the job is done.

It is not an easy life, but compared to the life of the rig workers who do hard manual labor all day it is easy and  is a good paying job for independent, self driven persons who enjoy working in an exciting and challenging environment.


If the condensed description of this oilfield job as I have related it so far sounds like something you would like to try then get your resume together, highlight the skills that pertain to this job, even if you do not have an oilfield background. Jobs that show a history of self direction and leadership,  such as military and mechanically related and technical jobs are a plus. What employers look for is knowledge of computers but nothing extreme, an ability to troubleshoot and solve problems independently and work with a minimum of direction as well as tolerate long hours and travel. Check out books from your local library such as "A Primer of Oil Well Drilling" and books on field geology and mineral identification.

A basic understanding of geology is required. A degree in Geology and Earth Science is a sure way to land a job with the top Oil and Gas Logging companies such as Halliburton. Smaller, mom and pop companies will hire anyone with a desire to learn so that is a good way to get a foot in the industry.
While mud logging jobs for the smaller land based companies can top out in the $50,000 range there is potential for much higher income working offshore and overseas for the majors once you have a few years of experience. It is also a good way to get a foot in the door of the oil and gas drilling industry and work your way up the ranks to a job with a salary of $100,000 or more a year as a mud engineer. Companies that hire mud logger trainees include Horizon Well Logging, Warren Logging, Selman and Associates, Geosearch Logging, Analog Services, Precision Well Logging and more. Get a good resume together, don't be afraid to call or cold call on these companies directly since they are always hiring in today's busy drilling market. Go to and search job postings and contact these companies directly.

Essential Books For those seeking oilfield employment:

  Helpful Links:  Rig Count Page   Schlumberger Dictionary   Baker Hughes                                   


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