Connection gas is distinct increase of gas above a normal background gas level when bottom up occurs after a connection. Connection gas is usually introduced during the drilling procedure of an oil field which allows the gas to reach to bottom of the wellbore. This gas can be controlled, injected and withdrawn from the oil well in between the connection by bringing minor changes in the drillstring movements. The connection gas is helpful in suggesting that the mud weight in the well hole is less than the formation pressure.
When a drilling operation is carried out in the wellbore, a small amount of gas is introduced into the path when mud pump is stopped. When a peak of small high gas is formed in a short span of time, it is usually made after every connection. The connection gas can be managed inside the wellbore by the mild effects of the short movements of a drillstring. On the other hand, the connection gas can also occur due to the temporary decrease in the total pressure while making a connection.