Wellsite geologists study and classify rock cuttings from oil and gas wells in order to determine how drilling should be started and how it should proceed

As a wellsite geologist, you'll use specialised tests, core samples and rock-cutting data to build up knowledge of the structure being drilled.

As an experienced geologist, you'll decide when tests should be carried out and, ultimately, when to stop drilling. You'll send reports and logs of completed drilling to the operations geologist and offer advice to oil company representatives. You'll also incorporate health and safety requirements in daily geological operations.

You'll liaise with drilling engineers, petroleum engineers and mudloggers during the course of projects.


As a wellsite geologist, you'll need to:

  • evaluate offset data before the start of drilling
  • analyse, evaluate and describe formations while drilling, using data from sources such as cuttings, gas, measuring while drilling (MWD) and logging while drilling (LWD) tools, and wireline logs
  • compare data gathered during formation evaluation measurement while drilling (FEMWD) with predictions made at the exploration stage
  • advise on drilling hazards and drilling bit optimisation
  • make decisions about suspending or continuing drilling
  • advise operations personnel on-site and in the operations office
  • attend rig meetings after each shift takes over and call the operations geologist with updates
  • acting as the representative of the onshore oil company geology team
  • supervise mudlogging, MWD and LWD, core logging and wireline services teams, and monitor quality control in relation to these services
  • keep detailed records, write reports, complete daily, weekly and post-well reporting logs and send these to appropriate departments
  • maintain up-to-date knowledge of MWD tools, such as gamma ray and resistivity, as geosteering becomes increasingly important
  • communicate regularly with onshore operations offices
  • take the lead on health and safety at the wellsite.


  • Typical starting salaries for those employed by oil and gas companies can range anywhere from £25,000 to £45,000.
  • At senior level, salaries can rise to in excess of £120,000.
  • New consultant wellsite geologists could earn between £350 and £450 per day, while those with more experience might earn around £800 to £1,000 per day.

Wellsite geologists are typically self-employed and are usually paid on a day rate basis. You're paid as long as drilling activity continues.

Salaries vary according to your experience, where you're working in the world and what type of organisation you work for. Bonuses and additional allowances can enhance your pay.

Income figures are intended as a guide only.

Working hours

Work depends entirely on drilling activity. Most wellsite geologists work around 150 days a year, but this could vary between 50 and 200.

In the North Sea, working hours are normally 12 hours on, 12 hours off continuously for two weeks, followed by a break ashore of two to three weeks. This varies depending on where in the world you work.

What to expect

  • You'll work on site on offshore rigs. The work is physically hard, often undertaken in dirty, noisy and bad weather conditions.
  • Almost all wellsite geologists are self-employed and work as consultants. The nearest opportunities are with North Sea oil rigs. Work is available on rigs throughout the world, some in very remote and hard-to-reach places. Travel to sites in some parts of the world can be complex and difficult.
  • Although there are still a few rigs where living conditions are basic, on most they are very good, with meals and laundry service provided. Gyms and snooker rooms are also often available. Alcohol and recreational drugs are not allowed on rigs.
  • There are currently very few women working in this area.
  • Considerable disruption to your personal and home life is to be expected.


You'll usually need a degree in geology or in another earth science containing a substantial amount of geology to become a wellsite geologist. Joint degrees with geology, including sedimentology, are acceptable.

Entry may also be possible with one of the following subjects:

  • applied physics
  • chemistry
  • geochemistry
  • geophysics or geotechnology
  • mineral or mining engineering
  • physics.

An MSc in geology may be helpful when looking for an entry-level position, particularly during economic downturns.

Search postgraduate courses in geology.

You'll usually need field experience as a mudlogger or logging geologist before moving into the role of wellsite geologist. Experience with a measuring while drilling (MWD) company is also useful.

Competition for posts varies depending on the state of the market.


You'll need to show evidence of the following:

  • excellent oral and written communication skills
  • the ability to work independently, as well as within a team of multidisciplinary professionals
  • analytical and critical thinking skills
  • confidence in giving an opinion
  • the ability to evaluate complex information and make decisions at any hour, day or night
  • an understanding of the activity taking place in the well and its implications
  • sensitivity to different cultures and ways of working
  • leadership and supervisory skills
  • practical skills
  • the ability to work with sophisticated technology
  • strong mathematical and scientific analytical skills
  • the ability to get on well with others in and out of the working environment, as you'll be working and living with the same set of people, without respite, for several weeks
  • competence in IT, with the ability to use standard office programs and specialised software
  • the ability to cope with working under pressure.

Foreign language skills can be useful as you'll be living and working with people from a range of different countries.

All rig personnel, including wellsite geologists, are required to pass several tests of physical fitness and survival. Offshore fire qualifications are normally required.

Work experience

It's unlikely you'll get a job as a wellsite geologist straight from university and you'll usually need to build up experience in the field first. You may start work as a mudlogger before progressing to the role of data engineer - this is the most experienced role in the mudlogging team. Opportunities depend on the state of the jobs market and you may need to change employer to progress.

Other ways of entering this career, may be through logging while drilling (LWD) or wireline logging roles.

You'll need to be committed, hardworking and determined as it can take time to achieve the position of wellsite geologist. Recommendation from a senior geologist who has experience of your work will enhance your chances of getting work.

Find out more about the different kinds of work experience and internships that are available.


Very few people in this role work directly for oil or gas companies. Most are employed on a contracting basis for specialist consultancies who supply wellsite geologists as and when required.

The companies that specialise in geological services are small to medium-sized. These provide most opportunities for wellsite geologists.

Other companies may offer wellsite geology as another service alongside drilling services, mainly employing independent consultants on a daily rate. This means that wellsite geologists are usually self-employed and are therefore responsible for meeting their own training and insurance costs.

The major consultancy groups tend to recruit regionally. However, this is a global industry and many UK wellsite geologists seek positions abroad where conditions may be more basic, but rates are still reasonably high. Many contracts are short term but well paid.

Longer-term contracts can give more security but are often less well paid. The exploration and extraction business is worldwide and therefore British nationals compete with those from other countries.

Look for job vacancies at:

You can also search for companies using directories of oil companies worldwide. These include:

In good years, the main specialist companies welcome speculative applications. However, most wellsite geologists are recruited by recommendation from others.

Professional development

There is no formal wellsite geology qualification. However, you'll generally have undertaken training in a range of areas in previous roles before beginning work as a wellsite geologist.

Courses for those who are new to wellsite geology are provided by companies such as HRH Geology and RPS.

You'll need to keep your skills and knowledge up to date throughout your career and also learn about new technologies and processes.

Typical areas of training include:

  • wellsite and offshore safety management
  • risk assessment
  • control of substances hazardous to health (COSHH)
  • wellsite operations
  • wellsite geological procedures
  • formation evaluation of wireline
  • abnormal pressure interpretation
  • FEMWD logs.

As an independent consultant, you'll be expected to put yourself through such courses, at your own cost, in order to keep your skills up to date.

Several of the geological services organisations that recruit staff also run training courses delivered at their premises or in-house at a company site or other venue.

Career prospects

Before getting a post as a wellsite geologist, you'll probably have built up experience in the field as a mudlogger or data engineer. You may also have a relevant MSc and direct experience of working as a geologist for an oil company.

As an independent consultant, you'll be largely responsible for your own career development. The best way to maintain some continuity of work is to develop a good working relationship with one or two oil companies and become their preferred contractor.

You should aim for chartered geologist (CGeol) status through The Geological Society. Becoming chartered shows that you're a competent professional with a high level of knowledge, skills and experience. Find out more at The Geological Society - Chartership and Professional.

Some wellsite geologists go on to become operations geologists for oil companies, which may be on a long-term contract requiring relocation or on a rotating contract. Others might undertake further training (usually self-funded) and become petrophysicists or reservoir engineers for oil companies.

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