The non-magnetic drill collar is made from specially treated steel alloys so that it does not affect magnetic surveying instruments. They aim to isolate directional survey instruments from magnetic distortion due to the steel drill string. Non Magnetic Drill Collar Function The magnetic survey instrument is influenced by the presence of a magnetic field around …
In general, the neutral point can be defined as the point in the drill string where there is a change from tension to compression in the axial stress or the point that is zero tension and zero compression. The location of this neutral point depends on WOB and the Bf buoyancy factor (that depends on …
Pre-job Requirements Pre-job Requirements An operating company wishing to use a Measurement While Drilling system must first decide: Where several different tools meet all the job requirements, some operators have a deliberate policy of trying out all the different systems to assess reliability and cost-effectiveness (check also oil well drilling well cost per foot). The …
All MWD sensors used in the downhole tool must be rugged enough to withstand the harsh environment. Only one of the systems currently available has the facility to change out damaged components (sensor package/electronics) without tripping the whole bottom hole assembly out of the hole. The failure of one sensor may not necessarily mean that …
All the Measurement While Drilling MWD systems commercially available is based on some form of mud pulse telemetry. Although several different companies in oil and gas field offer MWD services, there are certain similarities among the systems being used. The major components of the MWD tools mud pulse telemetry system are shown in Fig. 1. …
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 …
Dogleg severity is a measure of the amount of change in the inclination, and/or azimuth of a borehole usually expressed in degrees per 100 feet of course length. In the metric system, it is usually expressed in degrees per 30 meters or degrees per 10 meters of course length. All directional drilling wells have changes …
Planning & calculating a horizontal wellbore differs from planning normal directional drilling wells for oil and gas. In a typical directional wellbore, the target is usually described as a departure at a certain TVD. The target has tolerances in the horizontal plane (North and East). In a horizontal well, the target is commonly described by …
A conventional rotary drilling assembly is typically used when drilling a vertical well, or a deviated well’s vertical or tangent sections. When using an RSS Rotary Steerable Assembly or Non-Rotating Steerable Mud Motor Assembly in a deviated well, it is, of course, possible to drill the tangent sections of the well with the steering action. …
Sidetracking for oil wells is drilling a hole around unrecoverable junk, such as a stuck drill string ( Check also Pipe Sticking problem); it is necessary to place a cement plug above the junk at a required depth that will allow sufficient distance to kick off the cement plug and drill around, bypassing, the original …