Fiber-optic gyroscopes (FOGs)-based Measurement While Drilling system (MWD) is a newly developed instrument to survey the borehole trajectory continuously and in real time. However, because of strong vibration while drilling, measurement accuracy FOG-based MWD deteriorates. It urgent improve drilling. Therefore, this paper proposes an innovative scheme for error MWD. Firstly, nonlinear models F...

Clayey soil found in coal mines in Appalachian Ohio is often sold to landfills for constructing Recompacted Soil Liners (RSL) in landfills. Since clayey soils possess low hydraulic conductivity, the suitability of mined clay for RSL in Ohio is first assessed by determining its clay content. When soil samples are tested in a laboratory, the same engineering properties are typically expected for ...

The process of borehole drilling is a nonlinear and many dimensional process. During drilling it is possible occurrence of some complications (for example transition of drilling tool in layer with anomalous pressure). New method of identification of rock layers with anomalous pressure was proposed and tested on real plant data.

BACKGROUND Microfracture and drilling are bone marrow-stimulation techniques that initiate cartilage repair by providing access to cell populations in subchondral bone marrow. This study examined the effect of hole depth and of microfracture versus drilling on subchondral bone repair and cartilage repair in full-thickness chondral defects. HYPOTHESES Repaired subchondral bone does not reconst...

The Bangladesh Arsenic Mitigation and Water Supply Program (BAMWSP) has compiled field-kit measurements of the arsenic content of groundwater for nearly five million wells. By comparing the spatial distribution of arsenic inferred from these field-kit measurements with geo-referenced laboratory data in a portion of Araihazar upazila, it is shown here that the BAMWSP data could be used for targe...

RESEARCH ARTICLE Study of Cyclic Fracturing in Vertical CBM Wells Ting Li and Ji-fang Wan Hubei Cooperative Innovation Center of Unconventional Oil and Gas, Yangtze University, Wuhan 430100, P.R China Petroleum Engineering College of Yangtze University, Wuhan 430100, P.R China Key Laboratory of Drilling and Production Engineering for Oil & Gas, Hubei Province, Wuhan 430100, P.R China Mechanical...

Received: August 15, 2016 Revised: January 11, 2017 Accepted: February 14, 2017 Abstract: Background: Since the fragile anisotropy of shale, it is difficult to carry out laboratory experiments of geostress by shale cores. The existing geostress calculation model that is based on the homogeneous hypothesis also cannot meet the accuracy requirement. Therefore, it is necessary to establish the new...