no tillage systems can reduce operating costs, enhance soil organic matter, ameliorate soil structure and prevent environmental damage caused by stubble burning. however, the lack of an appropriate direct drill for the hardened soil of arid areas reduces adequate soil-seed contact and, thus, the system has shown contradictory results in past tests. developing a direct drill to place the seed an...

We propose a method for verifying persistence of nonlinear hybrid systems. Given some system and an initial set of states, the method can guarantee that system trajectories always eventually evolve into some specified target subset of the states of one of the discrete modes of the system, and always remain within this target region. The method also computes a time-bound within which the target ...

A ball cage flexible drill pipe is a new type of ultra-short-radius drilling tool, which consists multiple joints hinged together. During the process, members will come into contact and wear, reduces efficiency load transfer. The multi-body collision dynamics model was proposed to study performance pipe. method considered influence borehole curvature. kinematic equations were established. Lanka...

Abstract Compared with conventional drilling methods, the method of horizontal wells a slim hole (HW‐SH) has advantages, such as high productivity, environment‐friendliness, and low costs. However, during process, narrow annulus may become blocked, which lead to an increase in pressure if wellbore is not clean. This often leads serious accidents, sticking leaking formations. Many models have be...

According to the situation of multi hole machining with linear circular flange flange parts, a device is analyzed and designed, which can process multiple flange holes at the same time, and the design of the device including fixture design and multi spindle box design. the three dimensional modeling and analysis software is used, make a study on the design and manufacture of the flange hole of ...

Digital oilfield is the main means to increase production and income. Developing ultra-short radius sidetracking horizontal wells in old requires high-performance well trajectory control. In this paper, flexible drill pipe designed by bionics principle, logging tool monitor borehole real time using gamma ray technology. The combination of can realize remaining oil recovery between dense pattern...

It is planned to install a front monitor impulse radar on the surface of the rotating drill of tunnelling machines in order to detect obstacles such as casing pipes of vertical borings. The conventional aperture synthesis technique can no more be applied to such cases because the radar image of a pipe does not constitute a hyperbola as is the case for linear scanning radars. We have developed a...