Friday, February 14, 2014

Onshore Drilling (Part 1)

Drilling into the Earth in the hopes of uncovering valuable resources is nothing new. In fact, the digging of water and irrigation wells dates back to the beginning of recorded history. At first, these wells were primarily dug by hand, then by crude stone or wood tools. Metallurgy brought about the use of iron and bronze tools to delve beneath the Earth’s surface, and innovations led to more efficient ways of removing debris from the newly dug hole. The first recorded instance of the practice of ‘drilling’ holes in the ground came about around 600 B.C., when the Chinese developed a technique of repeatedly pounding bamboo shoots capped with metal bits into the ground. This crude technology was the first appearance of what is known today as ‘percussion drilling,’ a method of drilling that is still in use. Much advancement has been made since these first bamboo drilling implements. This section will cover the basics of modern onshore natural gas drilling practices. Laversab oilfield systems equips its clients with the technology and tools to expedite the drilling process.

There are two main types of onshore drilling. Percussion, or ‘cable tool’ drilling, consists of raising and dropping a heavy metal bit into the ground, effectively punching a hole down through the earth. Cable tool drilling is usually used for shallow, low pressure formations. The second drilling method is known as rotary drilling, and consists of a sharp, rotating metal bit used to drill through the Earth’s crust. This type of drilling is used primarily for deeper wells, which may be under high pressure.

Cable Tool Drilling

Cable tool, or percussion drilling, is recognized by many as the first drilling method employed to dig wells into the earth for the purpose of reaching petroleum deposits and water. This method is still in use in some of the shallow wells in the Appalachian Basin, although rotary drilling has taken over the bulk of modern drilling activities.

The basic concept for cable tool drilling consists of repeatedly dropping a heavy metal bit into the ground, eventually breaking through rock and punching a hole through to the desired depth. The bit, usually a blunt, chisel shaped instrument, can vary with the type of rock that is being drilled. Water is used in the well hole to combine with all of the drill cuttings, and is periodically bailed out of the well when this ‘mud’ interferes with the effectiveness of the drill bit.