Know your English

out of the borehole and punch small holes into the casing. More often than not, the pressure inside the well is sufficiently lower than in the surrounding rock for the hydrocarbons to start flowing into the well and rise up on their own. And as they rise, they are forced to exit at the top via a narrower tube — which is installed to, among other things, encourage the fluids to flow in only one direction (out).

The flow of hydrocarbons ends the completion stage and begins the production stage, when the most important aspects of the extraction operation are the systems at the well’s head controlling its outflow using valves. Sometimes, the pressure difference may be too low to bring the hydrocarbons to the surface. A common solution in some oilrich sites is to use pump jacks, facilities seen dotting the American midwest with a hammershaped piston moving up and down in languid fashion. They draw mechanical power from, say, an engine to lift up hydrocarbons from the bottom of a well. Some longstanding wells may require additional components or having old ones replaced to get more hydrocarbon out of them; these tasks are called workovers.

The production profile of a well can be split into three phases: primary, secondary, and tertiary, depending on the methods required to maintain production. The primary phase banks on natural processes, like pressure differences between the reservoir and the well and less dense compounds floating to the top. Secondary interventions are concerned with inducing artificial pressure in the rock to maintain the differential (for example, by injecting water into it or diluting the hydrocarbon mix to help it flow better). The tertiary phase is focused on forcing the remainder into the well. Steam injection is a common example of such an enhanced recovery method. An onsite gas turbine generates electricity while its waste heat is routed to a steam generator. The resulting steam is pumped into the rock: its heat makes heavyoil hydrocarbons less viscous and more willing to flow while its pressure pushes them out. When recovering petroleum, for example, the well may yield about 15%, 45%, and 15% of its hydrocarbon volume in three respective phases.

What happens when a well is depleted?

As the extraction rates indicate, a well needn’t be fully depleted before the extraction process ends. The process’s economics matter greatly: the contractor may stop extraction if it’s no longer profitable to keep extracting from a well.

A well thus abandoned needs to be plugged so that its contents — both the hydrocarbons and the gases accumulating in the borehole— don’t escape into their surroundings. These plugs can be temporary, in case the project proponent wishes to recommission it later, or permanent. A common issue with improperly plugged wells is that the plugs deteriorate and fail, either because of quality issues or due to nearby disturbances.

The most exhaustive way to conclude operations at a well, whether on land or offshore, is to decommission it, but this process is expensive and often commercially infeasible for the proponent. Improperly abandoned wells are a major source of methane emissions — to go with the emissions released during the production and use of various components required to extract hydrocarbons.

One 2018 study estimated that 9,000 oilfields in 90 countries released 1.7 billion tonnes of carbon dioxide in 2015 alone.

“Grin like a Cheshire cat (C. N. Bhagavan, Hyderabad).”

“It means ‘to be constantly smiling widely for no apparent reason’. It has a connotation of ‘smugness or vacuousness.’ The expression dates from the 18th century and was popularised by Lewis Carrol through his Alice’s Adventures in Wonderland. When Alice asked the Duchess why the cat grinned so broadly and inscrutably, the Duchess said, “It’s a Cheshire cat and that’s why”. The Cheshire cat in the book used to disappear, leaving behind its grin! It is believed that in the 18th century, Cheshire cheese was sold in the shape of a cat with a grin on its face. From this we get the expression.”

“Finger (C. Jeyaraj, Madras).”

“In Indian languages, no distinction is made between ‘fingers’ and ‘toes’: ‘finger’ is used for the movable parts at the end of the hands as well as the feet. In English, ‘toe’ refers to the movable parts at the end of the feet. The names of the fingers are: thumb, index finger or forefinger, middle finger, ring finger, little finger. Sometimes the little finger is called ‘baby finger.’ It is also called ‘pinkie’ by Scots and Americans.

There are no special names for the toes. They are numbered one to five. You refer to the big toe, second toe, third or middle toe, fourth toe, little or baby toe. In Latin, ‘index’ means ‘the forefinger.’ The fourth finger was used as the ring finger by the Romans and the Greeks as they thought that a nerve ran through it to the heart.”

“Letter of the 6th instant (A. G. Manoj Saldana, Shimoga).”

“‘I received your letter of the 6th instant’ means ‘I received your letter dated 6th of this month’. ‘Instant’ means ‘of the current month’. This was being generally used in commercial correspondence, though now it is rarely used in Englishspeaking countries. It is widely used in India in private and business correspondence. Like Indian English, there is also Indian business English and it has an archaic flavour.” “Putsch (G. Sedouram, Pondicherry).” “It means ‘a sudden, secretly planned attempt to remove a government by force.’ The ‘u’ is pronounced like the ‘u’ in ‘put’ and tsch’ like the ‘ch’ in ‘touch.’ It is a German word.

The current topic of discussion is the putsch in the Soviet Union.”

Published in The Hindu on September 17, 1991.