Showing papers on "Overpressure published in 1988"

Pore pressure formation evaluation while drilling

Abstract: Formation strength and other measurement while drilling parameters are combined in a formation volumetric analysis which produces not only the traditional volumetric components of clay volume, mineral volume, total porosity, and water filled porosity, but also, in shaley formations, an excess or overpressure porosity. The overpressure porosity is then utilized to generate an indication of pore pressure which in turn is used in the drilling process as an aid in determining the lowest optimal drilling mud weight for most efficient drilling without incurring excessive risks of a blowout arising from an overpressured formation.

Modeling the occurrence of overpressures on the Scotian Shelf, offshore eastern Canada

Abstract: Many wells on the Scotian Shelf, offshore from Nova Scotia, have drilled into overpressured zones. In particular, the wells comprising the Venture gas field have all encountered overpressures at depths below 4.5 km. The characteristics of the overpressure zones in the Venture field vary in some important details from overpressured zones on the U.S. Gulf Coast. In the Venture field the shales in the overpressured zones are observed to be normally compacted and interbedded with layers of overpressured sandstones. This is in contrast to the Gulf Coast, where the shales in the overpressure zone are undercompacted. Resistivity logs, sonic logs, and bulk density logs all provide some indications of overpressures in the Venture field but are not as unequivocal indicators of overpressure as they are on the Gulf Coast. Theoretical investigations of the causes of overpressures in an environment such as the Venture field show that overpressures are unlikely to be caused by loading of sediments. The most probable cause of overpressures is recent and continuing fluid generation, which is related to the transformation of kerogen to hydrocarbons. Limits are placed on the average permeabilities and fluid generation rates which are required if overpressures are to be produced by fluid generation.

Sonic boom loudness study and airplane configuration development

Abstract: Sonic boom wave form parameters as related to loudness were investigated analytically. The parameters studied include rise time, duration, maximum overpressure and initial overpressure. The design criteria of a 72 dBA for corridors and 65 dBA for unconstrained flight were chosen based on a review of human response testing. The 72 dBA criterion suggests that 1.0 psf shock waves may be acceptable. On that basis, acceptable low sonic boom wave forms were explored with respect to cruise conditions, aerodynamic lifting length requirements and configuration design at M 1.5 and M 2.4. An M 2.4 baseline arrow wing configuration was studied as a possible vehicle for M 1.5 cruise overland. Modifications made to approach the low boom wave form included a slightly longer forebody, staggered nacelles, a lifting arrow wing horizontal tail, and carefully tailored lift and volume elements. The same wave form criteria applied for M 2.4 cruise results in a low boom configuration that has significant weight, length and balance penalties. Further detailed design work is required to reach the target wave form and resultant loudness level for overland cruise at M 1.5. These results so far suggest that a properly designed M 2.4 overwater configuration may be capable of M 1.5 overland operation with sonic boom noise characteristcs that meet the criterion.

Uses of pressure and temperature data in exploration and new developments in overpressure detection

Abstract: Pressure and temperature data from wireline logs and seismic-velocity analysis can be used in deep overpressures to aid in prospect evaluation. Properly interpreted seismic-velocity analysis in deep water can yield maturation and migration information. Use of a modified approach to the d exponent and use of measurement-while-drilling (MWD) data have proved successful in deepwater pressure detection.

Method for cleaning service water systems or heating installations and device for carrying out the method

Abstract: A method for cleaning service water systems or heating installations to which overpressure is applied from a central supply is characterised in that a) by separation from the central supply (9) and simultaneous opening of the service water system (23) or of the heating installation, the overpressure is suddenly reduced, specifically in such a way that there is a slight evacuation against the direction of flow in operation; b) closure is performed again after a short time and the overpressure builds up; c) the operations of pressure relief and pressure application are multiply repeated successively, and d) these operations are performed under automatic control. In the device for carrying out the method, there is arranged in a main line (10) between the central supply (9) and the service water system (23) or heating installation a three-way valve (24) which can be adjusted by means of a motor (27) provided with a controller (28).

Method and apparatus for turbulent spinning for the production of fibre-bundle yarn

Abstract: In an air-swirl nozzle 1, an air-swirl flow of differing intensity and of the same direction of rotation is generated in a spinning chamber 6 and acts on a fibre sliver by means of overpressure channels 7a, 7b of differing length or of different diameters. This effect can be achieved by connecting the overpressure channels 7a, 7b to separate overpressure sources of differing intensity. The universal twist effect on the fed fibre bundle is also assisted by guide elements 17 for directing the air flow of differing intensity. This guide element is provided opposite the overflow channels 7a, 7b in the spinning chamber 6.

Vorrichtung zur klimatisierung des innenraums von personenkraftwagen.

Abstract: An air conditioning system for a vehicle has a coolant circuit with high and low pressure sections. To prevent overpressure, a venting valve dumps coolant into a low pressure store (11). On pressure reduction this stored coolant is valved back into the system. The dumping valve and the re-entry valve (13,14) are integrated into the same assembly for space saving and to reduce pipework. The size of the storage reservoir depends on the type of coolant used and the size of the system.

Encapsulated temperature switch

Abstract: An encapsulated temperature switch is proposed which, for use in corrosive environments and for protection against overpressure, has a metal housing (4, 6, 7) which is welded shut, and connecting leads (3) which are passed out through compression-glass bushings (9).

Detonation of fuel--airmixtures above the surface of the earth

Abstract: DETONATION OF FUEL--AIRMIXTURES ABOVE THE SURFACE OF THE EARTH A. A. Borisov, B. E. Gel'fand, S. A. Gubin, S. I. Sumskoi, and V. A. Shargatov The parameters of air shock waves from detonation of fuel--air mixtures located at identi- cal heights above the surface of the earth depend significantly on the radius of the spherical volume involved [I]. Mixtures containing 16% acetylene or 8% ethylene with total volume vary- ing from 1.4 to 27 m s were studied in [i]. The center of the balloon containing the fuel mix- ture and the pressure sensors were located at a height H = 3.5 m, eliminating the effect of the earthVs surface on the recorded shock wave parameters [i]. However, the experimental de- pendences of overpressure behind the shock wave front Ap on dimensionless distance ~ = r/to, presented in Fig, i, differ for different initial volume values (Vo = 4~r~/3). One-dimensional calculations of shock wave parameters for detonation of spherical volumes [2-4] indicate that for the given mixture composition the excess pressure behind the shock wave front is a unique function of I. In order to clarify the causes of the increase in shock wave intensity from detonation of large volumes of mixture a numerical modeling of flows in the detonation products and air was performed to analyze the data of [i]. A two-dimensional calculation technique with modified difference method i[5] was used. Changes were made to eliminate the possibility of:appearance of unreal parameter values near the contact surface (CS), which was distinguished explicitly. A difference grid with cylindrical coordinates Z, R, I00 “ 120 cells in size, was used. The center of the cloud was loca=ed at the point Z = H, R = 0, with~the surface of the earth being at Z = O. It was assumed that during the expansion process the detonation products are in a state of chemical equilibrium, with their state parameters being defined by an approximation of thermodynamic calculation data using the method of 14]. It was assumed that the detonation products do not mix with the air and do not burn up. For detonation of a volume of acetylene--alr mixture (to = 1.8 m) Fig. 2 shows a sequence of calculated shock wave structure positions. Three regions of change in shock wave parame- ters can be distinguished. In the meridional plane (Z,R) the dashed line denotes the bound- ary of region I, at every point of which the maximum pressure Pmax is reached in the incident shock wave and depends only on the distance to the center of the cloud r = ~(Z -- H) 2 + R =. At any point in region II Pmax is determined solely by the coordinate R and is realized when the Mach "wedge" passes through the point; in region III Pmax occurs behind the reflected shock wave. In region I the maximum pressure at a given point obtained by one-dimensional calculation with the technique of 14] coincides with the result of the two-dimensional calculation. It fol- lows from Fig. 2 that the line on which the experimental pressure sensors were located falls in region I. This means that within the framework of the uniform detonation product expansion model used, even for the largest of the fuel mixture volumes used in [I] the maximum pressure at Z = H should be reached on the front of the incident spherical shock wave at any distance R < 10to. This conclusion is confirmed by the data of Fig. 3, where isobars for t = 11.6 msec after detonation initiation are shown, as well as by the calculated functions Ap(1) of Fig. l, curve 3 for region I and on the surface of the earth for region II (line 4). It is evident f=om Fig. 1 that the calculation results for region I coincide with theexperimental data for Vo = 1.4 m 3 . Therefore the effect of dependence of p__. behind an air shock wave upon Vo of the fuel mixture observed in [i] cannot be explained ~increase in pressure in the shock wave reflected from the earthVs surface within the detonation model which assumes equilibrium ex- pansion of the products. The fact that rich mixtures were used in the experiments makes it possible that burnup of incomplete oxidation products may occur as they mix with air. If the quantity of acetylene Moscow. Translated from Fizika Goreniya i Vzryva, Vol. 24, No. 2, pp. 124-126, March- April, 1988. Original article submitted June 20, 1986. 238

Simulation Techniques for the Prediction of Blast from Underground Munitions Storage Facilities

Abstract: : Results are presented from a series of shock tube and 1:50 scale model high explosive (PETN) tunnel tests, designed to simulate underground chamber/tunnel explosions. Models consisted of straight and smooth chamber/ tunnel configurations with converging area changes. Experimental data are compared with predictions from a modified INBLAST computer code to which was added the blast wave propagation along the tunnel. Modifications were made either by the addition to INBLAST of shock tube equations for converging area change at the diaphragm, or by addition of the BRL-Q1D one-dimensional hydrocode. Effects of baffle induced tunnel area changes were included in the hydrocode when needed. Otherwise, the algebraic shock tube equations were used. The field test, in addition to internal blast pressure, measured the exit field pressures as a function of the chamber charge loading density. The free-field blast pressure was measured as a function of radial distance and angle of propagation with respect to the tunnel's long axis. Airblast; Blast suppression; Munitions storage; Tunnel attenuation; Baffles; Converging area; Overpressure; Blast waves; Exit blast; Shock tube; Underground storage.

Noise and Sonic Boom Impact Technology. PCBOOM Computer Program for Sonic Boom Research. Volume 1. Technical Report

Abstract: : The PCBOOM computer program, described in this technical report, calculates the location and magnitude of sonic boom overpressures on the ground due to supersonic flight under standard atmosphere and no wind propagation conditions. The program is intended for environmental planners and engineers who may need to estimate the noise impact from individual flights of supersonic military aircraft. The program runs on a Zenith Z-248 personal computer and also should run on most similarly configured IBM-compatible computers. The program contains information for all current military aircraft and allows updating for additional aircraft. The user can select either 'Quick look' computations which assume steady-state flight or detailed ray-tracing calculations which can handle non-steady flight and sonic boom focus conditions. Several types of simple maneuvers can be selected for computations; the program will also handle up to ten connected straight line segments. Flight segments from the MOAOPS library of supersonic combat training flights may also be selected. User-specified output for printer, plotter or screen includes tables of overpressures and graphic display of the sonic boom overpressure 'footprints' on the ground. The footprint plots show the location of all ray positions which exceed overpressures of a given level. Flight track, Mach number and altitude profile plots are also provided. This report summarizes the technical basis for PCBOOM. Two other reports provide a program users/computer operations manual and a program maintenance manual. PCBOOM; Computer program; Sonic boom; Hardware; Software.

Container with integral overpressure protection

Abstract: Beverage containers made of metal can be subjected during faulty operation of the pressure system to such a high pressure that they rupture. In order to provide a safeguard for this case, a tearing groove (14), which at least partially surrounds a surface region, is preferably worked into the top outwardly curved end wall (5). In the case of impermissible overpressure, transverse expansions occur in the material which lead to a crack beginning in the tearing groove (14), with the result that the bounded surface region folds outwards and the pressure medium can escape.

Air Force Boom Event Analyzer Recorder (BEAR): Comparison with NASA Boom Measurement System

Abstract: : AAMRL and NASA conducted a joint sonic boom test at Edwards AFB to field check the AAMRL Boom Event Analyzer Recorder (BEAR). Sonic boom overpressures were generated over the range of 0.5 pounds per square foot (PSF) to 36 PSF to verify the capability and establish the credibility of the BEAR over its full design range. These booms were simultaneously collected using the AAMRL BEARs and the long-established NASA Analog Sonic Boom Recording Systems. This report documents the results of these tests that show great agreement between the two systems and fully validates the BEAR systems for future Air Force boom measurement programs. This report also shows the AAMRL inverted microphone amount configuration obtains identical results as the flush microphone mount for recording sonic boom events. Acoustics, Noise, Sonic boom, Environmental noise, Recorders monitor, Community noise exposure.

Method of water-jet cleaning surfaces, for example of buildings

Abstract: The invention relates to a method of water-jet cleaning surfaces, for example buildings, in particular for removing dirt adhering to stone external surfaces, for example to porous limestone surfaces of room delimiting walls, with the aid of overpressure water jets. According to the invention, water jets with an overpressure of at least 5 bar are used for cleaning, and the speed of the water jets is increased to at least 1.5 times with narrowing of the flow cross-section. The accelerated water jets are divided into trickles by impacting, the - expediently spherical - water droplets divided into trickles are guided onto the surface to be cleaned and expediently into the pores of the surface.