Research on the Correction of the Linkage Hydraulic System of the Composite Hydraulic Gripper Used in Coal Mine Rigs

The research against the defect that the gripper of the rig using a traditional linkage hydraulic system always clips back to damage drill pipes when the rig starts to rotate is presented. The correcting solution of a kinetic pressure feedback system including a damper and an accumulator is described by establishing the transfer function of the linkage system and analysing major factors making the gripper to clip back. Taking the ZYWL-4000SY automatic rig for instance, the linkage hydraulic system after correction is compared with that of before in simulating analysis and the correcting solution is verified by both lab and field tests. The results show that the corrected gripper works well without hurting pipes and the rig operates in good and stable condition. The theoretical foundation and method are provided to design and test the linkage function of the composite hydraulic gripper of other similar rigs.

18 3/4" 15000 Psi Shear Anything KBOS for Subsea Well Applications

Kinetic Pressure Control has developed the 18 ¾" 15000 psi blowout stopper (KBOS) system for applications on all subsea well activities. The 18 ¾" 15000 psi systems builds upon the successful development of the 5-1/8" 15000 psi KBOS system for surface BOP applications[5]. The system can be configured within the existing subsea BOP, by replacing a casing shear ram or blind shear ram, or can be configured as a shut-in device below the BOP. The KBOS system provides a significant improvement over existing shear ram technology, providing the ability to shear/seal any items in the wellbore, which reduces the likelihood of a blowout, resulting in an improved risk profile. The KBOS is a proprietary design which uses a pyro-technical, electrically initiated process the actuate the shearing process. The system has been designed and tested to actuate and shear/seal in milliseconds, under full wellbore flowing conditions and meets NACE/ISO sour service requirements without exemptions. The control system includes real-time monitoring and function testing capabilities, and requires minimal in-service maintenance, as the working components are isolated from the wellbore fluids. A computational predictive model has been developed, with a test regime conducted to validate the model results. A full qualification program, with 3rd party certification, has been completed to industry standards. Shearing tests have been conducted for a large range of tubulars which have been challenging to shear with existing technology. These include: 9 ½" drill collars, combinations of large OD casing and inner strings, high strength drill pipe and tool joints, wireline, and production tubing. A subsea test of the system was successfully performed in 2019 to shear large OD casing and inner string. The KBOS system utilizes technology from other industries (ballistics, military, automotive) to provide improved shearing and sealing capabilities for all well activities (drilling, completion, intervention). The improved shearing/sealing capacity and reduced time enable a reduced likelihood of a blowout and improved risk profile

An efficient method for unfolding kinetic pressure driven VISAR data

Velocity Interferometer System for Any Reflector (VISAR) [Barker and Hollenbach, J. Appl. Phys. 43, 4669 (1972)] is a well-known diagnostic that is employed on many shock physics and pulsed-power experiments. With the VISAR diagnostic, the velocity on the surface of any metal flyer can be found. For most experiments employing VISAR, either a kinetic pressure [Grady, Mech. Mater. 29, 181 (1998)] or a magnetic pressure [Lemke et al., Intl J. Impact Eng. 38, 480 (2011)] drives the motion of the flyer. Moreover, reliable prediction of the time-dependent pressure is often a critical component to understanding the physics of these experiments. Although VISAR can provide a precise measurement of a flyer’s surface velocity, the real challenge of this diagnostic implementation is using this velocity to unfold the time-dependent pressure. The purpose of this paper is to elucidate a new method for quickly and reliably unfolding VISAR data.

Ionospheric feedback effects on the quasi-stationary coupling between LLBL and postnoon/evening discrete auroral arcs

We discuss a model for the quasi-stationary coupling between magnetospheric sheared flows in the dusk sector and discrete auroral arcs, previously analyzed for the case of a uniform height-integrated Pedersen conductivity (ΣP). Here we introduce an ionospheric feedback as the variation of ΣP with the energy flux of precipitating magnetospheric electrons (εem). One key-component of the model is the kinetic description of the interface between the duskward LLBL and the plasma sheet that gives the profile of Φm, the magnetospheric electrostatic potential. The velocity shear in the dusk LLBL plays the role of a generator for the auroral circuit closing through Pedersen currents in the auroral ionosphere. The field-aligned current density, j||, and the energy flux of precipitating electrons are given by analytic functions of the field-aligned potential drop, ΔΦ, derived from standard kinetic models of the adiabatic motion of particles. The ionospheric electrostatic potential, Φi (and implicitely ΔΦ) is determined from the current continuity equation in the ionosphere. We obtain values of ΔΦ of the order of kilovolt and of j|| of the order of tens of μA/m2 in thin regions of the order of several kilometers at 200 km altitude. The spatial scale is significantly smaller and the peak values of ΔΦ, j|| and εem are higher than in the case of a uniform ΣP. Effects on the postnoon/evening auroral arc electrodynamics due to variations of dusk LLBL and solar wind dynamic and kinetic pressure are discussed. In thin regions (of the order of kilometer) embedding the maximum of ΔΦ we evidence a non-linear regime of the current-voltage relationship. The model predicts also that visible arcs form when the velocity shear in LLBL is above a threshold value depending on the generator and ionospheric plasma properties. Brighter arcs are obtained for increased velocity shear in the LLBL; their spatial scale remains virtually unmodified. The field-aligned potential drop tends to decrease with increasing LLBL density. For higher values of the LLBL electron temperature the model gives negative field-aligned potential drops in regions adjacent to upward field-aligned currents.

Ducted compressional waves in the magnetosphere in the double-polytropic approximation

Small-amplitude compressional magnetohydrodynamic-type waves are studied in the magnetosphere. The magnetosphere is treated as a rarefied plasma with anisotropy in the kinetic pressure distribution. The parallel and perpendicular pressures are defined by general polytropic pressure laws. This double-polytropic model can be considered as a natural extension of the magnetohydrodynamic (MHD) model when the plasma is collisionless. Generalized dispersion relations for surface and body waves are derived and analyzed for an isolated magnetic slab. The waves are confined to the slab. For specific polytropic indices, the results obtained in the (i) Chew-Goldberger-Low (CGL) double-adiabatic and (ii) double-isothermal approximations are recovered.Key words. Magnetospheric physics (MHD waves and in-stabilities; plasma sheet; plasma waves and instabilities)