The ordovician limestone water inrush accident occurred during the excavation of 8228 working face in Tashan Coal Mine, Tongmei Group. On basis comprehensive geophysical exploration above and below well, order to find out development boundary flowing subsided column distribution characteristics broken body filled it, control by Grouting, boundary, influence zone, cementation fractured are found...

A variety of methods are examined in this study order to improve oil recovery from low-permeability heterogeneous reservoirs oil-saturated shale deposits. Calculations based on the fluid flow model revealed that water and gas injection was effective, horizontal directional wells, including those employing hydraulic fracturing evaluated study. Moreover, wells with vertical completions found be o...

BACKGROUND Optimal tunnel placement is critical in anterior cruciate ligament reconstructive surgery, yet the method used to drill the tunnels may compromise their placement. HYPOTHESIS An independent drilling method versus a conventional transtibial drilling method will place tunnels in different locations and produce reconstructions with different kinematics. STUDY DESIGN Controlled labor...

Directional drilling has evolved over the last few decades to become standard operational practice in the oil and gas exploration industry. One method of steering utilizes a technique known as magnetic Measurement While Drilling (MWD). Vector measurements of geomagnetic fields along a well-bore are used to determine it orientation. This method is advantageous in that it is inexpensive and effic...

Horizontal drilling is an important development in the petroleum industry and it relies heavily on guiding the drill bit with the aid of sonic logging, i.e. geosteering. The quality of sonic imaging depends heavily on the effective suppression of borehole waves and enhancement of weak reflection signal. To this end, we propose an approach to image the near-borehole structure using acoustic logg...

recognition of relationship between the present day stress state and fractures is very important in fractured reservoirs. fractures that are parallel or oblique to maximum horizontal stress have more tendencies to tensile deformation and tensile deformed fractures will be more permeable. the dalan formation is one of the main gas reservoirs of iran witch most of the production from this formati...

This paper considers downhole directional drilling systems in the presence of unexpected variations in steering force, input delays, measurement noise and measurement delays, and explores the application of L1 adaptive controller for the trajectory control problem. The Explicit Force, Finitely Sharp, Zero Mass (EFFSZM) model is used for the steering system, in which spatial delays, modeling ina...

Both shipboard and shore-based magnetic studies of Ocean Drilling Program (ODP) Leg 208 sediments produced poor-quality irectional data. A noisy inclination signal and a pervasive declination bias demonstrate that the sediments had been remagnetized nd/or deformed. In an attempt to characterize any deformation, we carried out anisotropy of magnetic susceptibility (AMS) experments on a suite of ...