The correct choice of the borehole in directional drilling is the mission of essential importance. Rational profile allows minimizing the work of deflection arrangement to the least possible depth, provides the necessary offset relative to the outfall of the allowable deviation intensity, the free passage of the drilling equipment through tubing, as well as trouble-free well exploiting in accordance with modern methods for long time.
Consequently, the profile of downhole must be chosen with minimum time consumption, investment volumes, allowing achieving the required a depth with no change project adjustments and accidents, ensuring adequate quality for long and trouble-free operation.
Nowadays are widely used and meet virtually all the geological, technical and technological requirements of drilling and production profiles of the following types:
- The tangential type of profile features three sections: vertical section, section of a set of zenith angle, site stabilization zenith angle extending to a depth of wells. This profile provides maximum deviation from the vertical wellbore with a minimum zenith angle, so it is preferred to use it in the case of multiple drilling. The profile either does not imply using any intermediate columns in wells of moderate depth or implies curvatures within the range provides in case of deep wells;
- S-shaped type of profile consists of four sections: vertical section, section of a set of zenith angle, site stabilization zenith angle and zenith angle falling area. The hallmark of this profile is the presence of a set of plots and the zenith angle of incidence, so in addition to the general 5-interval, 3 and 4-interval modifications are possible. This profile is taken advantage of when the need to establish intermediate casing strings, drilling wells from one platform, for example, on the high seas, is required. This profile provides an intermediate casing in the range of the second deviation.
- J-shaped is the type of profile consisting of two sections: a vertical section and a low-intensity set zenith angle along the major radius. The profile is used for drilling on layers beneath the salt domes, multiple drilling and opening the deep-lying objects.
Tangential and J-shaped profile types are typically preferred to the S-shaped so that they have no kinks; they improve the permeability of the tool and geophysical instruments, reduce the amount of work the deflection arrangement reduces the resistance force when moving the drilling and casing facilitates operating conditions well.
However, the proven industry experts will carry out a thorough examination prior to proceeding to initiating the works. A full development cycle in fact can be delegated to a single company: thus, if you are searching for a company to outsource borehole drilling tasks, you may want to consider the option of teaming up with European Geophysical Services. A seasoned company specializing in geophysics, boasting a triple A staff and an affordable pricing model, has been in borehole drilling for more than 9 years. The company will cope with a borehole drilling mission of any complexity, so feel free to get in touch with EGS reps to discuss the details.Read Article