BACKGROUND The Marcellus Shale is a vast natural gas field underlying parts of Pennsylvania, New York, West Virginia, Virginia, and Maryland. Rapid development of this field has been enabled by advances in hydrofracking techniques that include injection of chemical and physical agents deep underground. Response to public concern about potential adverse environmental and health impacts has led t...

Oil and gas drilling operations use drilling fluids (mud) to lubricate the drill bit and stem, transport formation cuttings to the surface, and seal off porous geologic formations. Following completion of the well, waste drilling fluid is often applied to cropland. We studied potential changes in soil compaction as indicated by cone penetration resistance, pH, electrical conductivity (EC(e)), s...

The natural convection flow over a surface embedded in saturated porous media is encountered in many engineering problems such as the design of pebble-bed nuclear reactors, ceramic processing, crude oil drilling, geothermal energy conversion, use of fibrous material in the thermal insulation of buildings, catalytic reactors and compact heat exchangers, heat transfer from storage of agricultural...

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...

But over the past 150 years, the noise levels in our oceans have increased significantly. This is due to human activity. The propeller noise from shipping has raised the baseline for low-frequency ambient ocean sound worldwide. There is noise produced by undersea construction, such as pile-driving (e.g., hammering posts into the seafloor, such as for docks or drilling platforms). Sonar is used ...

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...

OBJECTIVE The objective of the study was to evaluate the practicality and the validity of different surface treatments of self-drilling orthodontic mini-implants (OMIs) by comparing bone cutting capacity and osseointegration. METHODS Self-drilling OMIs were surface-treated in three ways: Acid etched (Etched), resorbable blasting media (RBM), partially resorbabla balsting media (Hybrid). We co...

As oil and gas production moves to ever more challenging areas, increased use of technology becomes increasingly important. One technology that can contribute towards achieving safe and economic production from such areas is computer-aided process engineering. We outline the use of such technology in two (of many) instances: Managed pressure drilling (MPD) for deep-offshore applications and nat...

The article provides information on the causes of drilling fluid absorption and research conducted during its absorption. It is known that some complications arise when a well. One them loss circulation. Absorption mainly depends several factors. main factors depend condition well, geological structure correctness processes performed drilling. Also, another factor has an effect, which type flui...

Bacterial tRNAs frequently have 4-thiouridine (s(4)U) modification at position 8, which is adjacent to the C13-G22-m(7)G46 base triple in the elbow region of the tRNA tertiary structure. Irradiation with light in the UVA range induces an efficient photocrosslink between s(4)U8 and C13. The temperature dependence of the rate constants for photocrosslinking between the s(4)U8 and C13 has been use...