Solids control equipment at the rig site is used to remove rock cuttings or low-gravity solids (LGS) from drilling fluids to allow the fluid to return to the active system in a re-usable condition. Typical equipment, such as shakers and centrifuges, remove LGS particles greater than 5-7 microns. Build up of finer solids in the fluid can create problems for efficient drilling such as drillpipe s...

OBJECTIVE To assess if the screw design (self-drilling/self-tapping) and the pilot hole tapping could affect the insertion torque and screw pullout strength of the screw used in anterior fixation of the cervical spine. METHODS Forty self-tapping screws and 20 self-drilling screws were inserted into 10 models of artificial bone and 10 cervical vertebrae of sheep. The studied parameters were th...

The magnetostratigraphy of Sites 748 and 750 of Ocean Drilling Program Leg 120 is reported. About 260 sediment cubes were stepwise demagnetized with alternating fields to determine their characteristic direction of natural remanent magnetization. In general, the characteristic inclinations of the single samples have values similar to the inclination values obtained from whole-core measurements ...

Rotary drilling belongs to the key methods of rock separation not only in mining, but also in wider areas of geotechnologies 1, 2 . The most efficient separation of rocks is in so-called volume area which can be achieved with the correct choice of work tool and work mode while taking into account the geomechanical properties of rock separation. Theoretical research of rock separation by rotary ...

[1] Drilling during ODP Leg 209, dredging, and submersible dives have delineated an anomalous stretch of the Mid-Atlantic Ridge north and south of the 15 200N Fracture Zone. The seafloor here consists dominantly of mantle peridotite with gabbroic intrusions that in places is covered by a thin, discontinuous extrusive volcanic layer. Thick lithosphere (10–20 km) in this region inhibits magma fro...

In drilling operation the design of a proper mud weight to avoid any instability’s is important. A low mud weight may cause breakouts around the borehole whereas a high mud weight can fracture the formation. Mud weight design is based on two main factors: the mechanical properties of formations being drilled and the state of in-situ stresses in the field. While drilling in soft formations are t...

Baseline characterization of concentrations and isotopic values of dissolved natural gases is needed to identify contamination caused by the leakage of fugitive gases from oil and gas activities. Methods to collect and analyze baseline concentration-depth profiles of dissolved CH4 and C2 H6 and δ13 C-CH4 in shales and Quaternary clayey tills were assessed at two sites in the Williston Basin, Ca...

We discuss the possibility of recording state in-situ stress in shape a rock core that is sampled using modified drilling method. This concept based on phenomenon cylindrical rock-core expands radially into slightly elliptical along its transverse cross-section when sample relieved anisotropic by drilling. The magnitudes and orientation stresses can, principle, be estimated from circumferential...