Underbalanced drilling technique involves drilling the formation with drilling fluids having lesser hydrostatic pressure than the formation pressure. The lesser hydrostatic pressure of drilling fluids can occur naturally or it can be formulated by adding certain substances like methane, air, or nitrogen (N2) in the liquid phase. This technique results in the inflow of formation …
During well control operations, the maximum allowable borehole fluid pressure at the casing shoe is normally considered to be the critical factor, based on the assumption that the weakest formation is at the shoe. For practical purposes, the corresponding pressure at the surface (Drilling MAASP or Maximum allowable annular surface pressure) is calculated through specific …
When manufactured, the new drill pipe will be subjected by the manufacturer to a series of mechanical, tensile, and hydrostatic pressure tests & inspections by API Specifications 5A and 5AX. This will ensure that the pipe can withstand specified loads. A joint of drill pipe will however be used in several wells. When it has …
The tripping pipe can be defined as running in or pulling out of the hole with the drill string. In this article, we have prepared a complete guide for who needs to learn its operations on the surface and who needs to understand its procedures to prevent any unforeseen problems. During such trips, the potential …
Well control operations are performed at reduced pump speeds or slow circulation rate in order to: Operation of the pump at a pressure too close to the setting of its relief valve is dangerous. If the relief valve opens, drilling fluid will flow back through the drill pipe and standpipe manifold. Circulation pressures at the …
In subsea situations, a pressure loss exists when circulating through the choke line due to the friction losses in the extended choke line running up from the BOP. This pressure loss is not accounted for in normal Slow Circulating Rate (SCR) measurements, which are taken while circulating up the marine riser (see Fig 1). In …
Conventionally, one will drill a well and use heavy drilling fluids to control the well pressures and to control the flow of cuttings from the well. Sometimes, using air or gas as the circulating medium or using light mud to drill in an underbalanced condition is beneficial. You must use a rotating drilling head when …
So far we have discussed directional drilling wells & horizontal wells (check also horizontal directional drilling calculations) in previous articles. This knowledge can be extended to understand multiple horizontal or directional wellbores drilled from a single wellbore. This technology, called multilateral drilling wells, allows reaching target depths at different bottom-hole locations. The technology of drilling …
The trend of international oil prices affects the nerves of global investors. The recent 2014 peak was more than US$100 per barrel, while this year’s drop was less than US$30 per barrel. How is international crude oil priced? Does the current crude oil (energy) have investment value? Noah Fortune is trying to find answers from …
The kick tolerance can be defined as the maximum volume of kick influx that can be safely shut in and circulated out of the well without breaking down the formation at the open hole weak point. Here In this article, we will explain kick tolerance calculations methods, formulas & the most important considerations. Kick tolerance …