https://doi.org/10.1016/S0376-7361(08)70209-7
Publisher Summary
This chapter discusses the way in which drilling fluids, drilling muds, well cuttings, and well-treatment chemicals contribute to pollution. Studies of well blowouts and possible development of communication between a fresh-water aquifer and oil-bearing sand have been made. The fact that the brines produced with oil and gas can contribute to pollution is well known but no universally satisfactory method of their disposal is available. Disposal of brine by solar evaporation in evaporating ponds has been investigated but final disposal of the residue salts needs further development. Some brine contains valuable minerals that are economically recoverable, and treatment or disposal of such brines should be coordinated with mineral-recovery processes whenever possible. Subsurface injection of oilfield wastes provides a good method for disposal of potential water pollutants, but the results are not always satisfactory. This disposal method has been blamed as the possible cause of earthquakes, and if a natural disaster, such as an earthquake, occurs, new faults or fractures in subsurface strata may provide communications between the strata containing the waste and fresh-water aquifer.
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Cyril,
Realistically, drilling operations can have minimum environmental footprint is the concept is selected correctly. In early 2000s, I worked offshore Russia in the Caspian sea. We drilled a few wells in the natural park area from a real zero discharge jack-up rig. The only discharge was cooling water from our diesel generators. This water goes through the tubes inside the machinery but without any physical contact with any mechanical parts of the generator sets. So, in fact you take sea water and drain the same sea water but of a slightly higher temperature. This attracts marine flora and fauna, migrating birds and even dragonflies. We did not discharge even water-based cuttings. There is obviously some minimum pollution by exhaust gas emission but with a modern engines it is not more than a small village can produce. We had environmental protectin authorities on our back doing spot checks on helicopter and looking for any violations of nature protection regulations. We did not pay any single fine. Cuttings, drilling mud, black and grey water, etc. were collected in special tanks and offloded onto supply vessels for onshore treatment facilities.
I am still surprised that 15 years later, even the most advertised Norwegian rigs are not that clean and safe as our rig was. We are still requested to provide means to dump the drilling wastes directly to sea for emergency cases. On my Russian rig, we would just stop drilling as the only option. Our offshore people have the photos of seals, snakes, birds and dragonflies resting on our rig, when we drilled in that natural park.
Very good insight views has been given on the subject by our colleagues . One of the worst case scenerio is well blow out leading to oil spills in offshore as well as onshore field which can cause alarming environmental damage.
Blowout is uncontrolled flow of high pressure formation fluid out of the well bore while drilling a hole. It is an accident which happens due to neglection in the drilling operation, causing mammoth loss to environment and company's finance. Please watch "Deep Horizon" movie to understand a real case in the north sea.
A blowout can happen not during drilling only. It can happen on the well that has been previously drilled, plugged and abandoned if the cement job had not been properly executed and accessed. I guess "Deep Horzion" is a Deepwater Horizon movie that hs nothing to do with real drilling operations. I cannot believe that a Senior Electrician will teach a CompanyMan (Drilling Supervisor) or a Senior Drilling Manager how to drill a well, how to run and evaluate the cement job and will be running across the rig without proper PPE to push an ESD button. It is a fiction movie based on the real story. But way-way-way fiction.
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