Wellsite geologist: Job description

Wellsite geologists study rock cuttings from oil and gas wells to determine what rock formations are being drilled into and how drilling should proceed. They identify critical strata from core samples and rock-cutting data and build up knowledge of the structure being drilled.

They are experienced geologists, deciding when specialised tests should be carried out and, ultimately, when to stop drilling. They send reports and logs of completed drilling to the operations geologist and offer geological advice to oil company representatives. They incorporate health and safety requirements in daily geological operations.

Wellsite geologists also liaise with drilling engineers, petroleum engineers and mudloggers during the course of projects.

Typical work activities

The work is based entirely on a rig and usually involves the following:

• evaluating offset data before the start of drilling;
• analysing, evaluating and describing formations while drilling, using cuttings, gas, FEMWD (formation evaluation measurement while drilling) and wireline data;
• comparing data gathered during drilling with predictions made at the exploration stage;
• advising on drilling hazards and drilling bit optimisation;
• taking full responsibility for making decisions about suspending or continuing drilling;
• advising operations personnel on-site and in the operations office;
• acting, in effect, as the representative of the onshore oil company geology team;
• supervising mudlogging, FEMWD and wireline services personnel and monitoring quality control in relation to these services;
• keeping detailed records, writing reports, completing daily, weekly and post-well reporting logs and sending these to appropriate departments;
• maintaining up-to-date knowledge of MWD (measuring while drilling) tools, such as gamma and resistivity, as geosteering becomes increasingly important;
• communicating regularly with onshore operations offices.