Saturday, August 8, 2009

Drilling Operations: Fishing & Well Control

Article submitted by: John Schiffner

For our purposes special drilling operations include directional drilling, fishing, and well control. Directional drilling is initially drilling the hole off-vertical for various reasons. Fishing is the operation crew members implement to retrieve an object in the wellbore that doesn't belong there and impedes drilling. Well control is the techniques crew members use to regain control of the well should formation fluids inadvertently enter the well.

A fish is a piece of equipment, a tool, or a part of the drill string that the crew of Heartland Energy Colorado loses in a hole. Drilling personnel call small pieces, such as a bit cone or a wrench "junk." Whenever junk or a fish exists in a hole, the crew has to remove it or fish it out otherwise they cannot continue to drill. Over the years, fishing crews have developed many ingenious tools and techniques to retrieve fish. For example, the crew can run an overshot into the hole to he fish. Crew members of Heartland Energy Colorado, make up the overshot on drill pipe and lower the overshot over the fish. Grapples in the overshot latch onto the fish firmly. Then the crew pulls the overshot and attached fish out of the hole.

Another fishing tool is a spear. Unlike an overshot, which the crew places over the fish, a spear then grips insde the fish and allows the crew to retrieve it. Other fishing tools include powerful magnets and baskets. The crew uses them to fish for junk. Since no two fishing jobs are alike, manufacturer and fishing experts have developed many other fishing tools to meet the unique needs of fishing crews.

Well Control
As mentioned earlier, one vital job drilling fluid should do is keep formation fluids from entering the wellbore. If enough formation fluids enter the wellbore, drilling personnel of Heartland Energy Colorado say that the well "kicks." A kick, if not recognized and properly handled, an lead to a blowout. A blowout can be a catastrophic event. In many cases, fluids in the blowout ignite and reduce the rig to a melted pile of junk.

Blowouts not only waste oil and gast but also threaten the lives of the crews working on the rig. Obviously drilling crews take a great deal of care not to allow blowouts, and in fact not too many occur at Heartland Energy Colorado. Because a blowout is a spectacular show and human lives are sometimes lost, a blowout often becomes a media event. Unfortunately, the impression may linger that blowouts are not the rarity they actually are. In fact, thousands of wells are drilled every year and very few of them blow out.

More articles by John Schiffner on Heartland Energy Colorado | Colorado Energy News | Heartland Energy

Saturday, August 1, 2009

The Formation of Oil (Part 1 of 2)

Dead organic matter must lie in either stagnant, oxygen-free waters at the bottom of the sea until buried or be buried quickly after death and achieve a concentration of one to three percent by weight to become a future oil reservoir, although this concentration can be as high as ten percent.  The next step is burying the organically rich sediment deep enough to generate the temperature and pressure necessary to transform organic matter to oil. 

With 7,000 feet of overburden, the pressure is sufficient to raise the sediment’s temperature to 150 degrees Fahrenheit, the minimum to produce a heavy and generally undesirable grade of crude oil.  Preferred light crudes are produced as one approaches 18,000 feet and 300 degrees Fahrenheit.  Beyond 18,000 feet, the temperature and pressure are sufficient to transform oil to graphite and natural gas. The oil window is 7,000 – 18,000 feet below the surface of the earth, meaning that sediments at river mouths must be buried between 1.5 – 3.5 miles of debris to produce oil by either the ocean bottom sinking or the surrounding land mass rising or a combination of both.

The properties of the oil depend on the type of organism, its concentration, depth of burial and the nature of the surrounding sediment.  Oil properties vary from one field to another and no two fields have exactly the same properties.  Commercial grades of crude are really a mix of oil from different oil fields in the same region that have similar properties.  A few are from different oil fields with dissimilar properties such as Urals, a specified mix of light sweet crude from western Siberia and heavy sour crude from the Ural region of Russia.

Heartland Energy Colorado is one of the top hydrocarbon-based energy providers in the USA. They have many drilling locations throughout the country and remain one of the top producers of US oil & gas companies. For more information on Heartland Energy Colorado, see Heartland Energy Development Corporation online.