Sand Penetration Research Articles

Subsurface Valleys and Geoarcheology of the Eastern Sahara Revealed by Shuttle Radar

The shuttle imaging radar (SIR-A) carried on the space shuttle Columbia in November 1981 penetrated the extremely dry Selima Sand Sheet, dunes, and drift sand of the eastern Sahara, revealing previously unknown buried valleys, geologic structures, and possible Stone Age occupation sites. Radar responses from bedrock and gravel surfaces beneath windblown sand several centimeters to possibly meters thick delineate sand- and alluvium-filled valleys, some nearly as wide as the Nile Valley and perhaps as old as middle Tertiary. The now-vanished major river systems that carved these large valleys probably accomplished most of the erosional stripping of this extraordinarily flat, hyperarid region. Underfit and incised dry wadis, many superimposed on the large valleys, represent erosion by intermittent running water, probably during Quaternary pluvials. Stone Age artifacts associated with soils in the alluvium suggest that areas near the wadis may have been sites of early human occupation. The presence of old drainage networks beneath the sand sheet provides a geologic explanation for the locations of many playas and present-day oases which have been centers of episodic human habitation. Radar penetration of dry sand and soils varies with the wavelength of the incident signals (24 centimeters for the SIR-A system), incidence angle, and the electrical properties of the materials, which are largely determined by moisture content. The calculated depth of radar penetration of dry sand and granules, based on laboratory measurements of the electrical properties of samples from the Selima Sand Sheet, is at least 5 meters. Recent (September 1982) field studies in Egypt verified SIR-A signal penetration depths of at least 1 meter in the Selima Sand Sheet and in drift sand and 2 or more meters in sand dunes.

Jet Piercing of Oil Sands

This paper describes the results of an experimental investigation of the penetration of oil sands by continuous and pulsed high-pressure water jets. Both laboratory and field tests were carried out to determine the influence of the jet dynamic pressure, nozzle diameter, pulse frequency, and total jetting time upon the depth of penetration.

Impact penetration of sand. Technical note : Can Geotech J, V17, N1, Feb 1980, P127–131

Impact penetration of sand. Technical note : Can Geotech J, V17, N1, Feb 1980, P127–131

Impact penetration of sand

This paper describes an instrumented impact penetrometer suitable for the measurement of in situ properties of soils. The velocity and depth of penetration at any instant are calculated from the deceleration record. Results are presented from a series of tests on a dry sand target for a range of impact velocities up to 12 m/s.

Naturally Occurring Gas Hydrates in the Mackenzie Delta, N.W.T.

ABSTRACT Two exploratory wells drilled in the Mackenzie Delta area of the Northwest Territories in 1972 by Imperial Oil Limited encountered shallow sand reservoirs containing gas hydrates -- an ice-like mixture of natural gas and water. These hydrocarbon-bearing sands underlie a thick zone of permafrost and are within the required pressure-temperature regime for naturally occurring gas hydrates. A significant increase in the amount of formation gas in the drilling mud occurred during penetration of these hydrate-bearing sands. Although wireline logs and drill cuttings indicated the sands to be very porous, test results showed their permeability to be extremely low. This is characteristic of hydrate-filled reservoirs. Because hydrates decompose at warm temperatures, yielding very high pressures if confined, it is dangerous to attempt to recover hydrated core with a conventional core barrel. Problems due to mud gasification, which occurs while drilling hydrates, can be minimized by using cool mud and by casing off the hydrate zones before drilling to deeper objectives.

Simulating the effects of gravitational field and atmosphere on behavior of granular media

Designs for structures, vehicles, and equipment to be used on the surfaces of the moon and Mars cannot be optimized without a knowledge of how soils in various gravitational fields and atmospheric conditions behave when subjected to static and dynamic loading. Strengths of the lunar and Martian gravitational fields (0.17 and 0.38 times terrestrial, respectively) can be simulated for approximately 30 sec by flying the KC-135 aircraft through appropriate parabolas. Effects of gravitational field on explosion crater formation and projectile penetration have been investigated. Techniques devised for use in these tests are discussed. Diameters of explosion craters and depths of projectile penetration in sand were found to increase as the gravitational field strength decreased. Atmospheric pressure variations down to ultra-high vacuum are significant in the behavior of rock powders. Approaches used in ultra-high vacuum tests on adhesion and compressibility of basalt powders are discussed. The forces of adhesion between rock powders and metal alloy surfaces were noted to be greater in ultra-high vacuum than in air. The forces required to compress slowly a basalt powder are greater after bakeout and exposure to ultra-high vacuum than when this rock powder is tested at atmospheric pressure.

Experimental study of projectile penetration in Ottawa sand at low velocities.

Experimental study of projectile penetration in Ottawa sand at low velocities.

Performance of a Solution Gas Drive Reservoir, Rosenwald Pool, Oklahoma

Abstract The Rosenwald pool, Okfuskee County, Okla., was discovered in June, 1949. Production is from the Union Valley limestone and Cromwell sand, both of Pennsylvanian age, at an average depth of about 3,450 ft. The Union Valley lies conformably on the Cromwell with the two formations forming a common reservoir. The pool is a stratigraphic trap with the limits defined by a pinchout of the sand and a loss of permeability in the lime. The pool as fully developed consisted of 31 producers drilled on 10-acre spacing. All wells flowed upon completion, with initial productions ranging from 40 BOPD for edge wells to as much as 1,600 BOPD where good Cromwell sand development was encountered. Initially only a few feet of sand penetration was taken, for fear of encountering bottom water. Early in the life of the reservoir, performance calculations were made using Muskat's differential form of the material balance equation for dissolved gas drive reservoirs, in an attempt to predict the future production history of the pool. A kg/ko curve for the performance calculations was constructed from data of other pools which have produced from Cromwell or sands similar in texture to the Cromwell. Subsequently the reservoir has been essentially depleted by primary means, enabling a comparison of the actual performance with that predicted. Actual recovery was 20 per cent of the original oil in place as compared to the prediction of 26½ per cent. Laboratory-determined relative permeability ratios and the assumed ratios used in the performance calculations are compared with those calculated from the field performance. By the end of 1953 most of the wells had become marginal producers and the pool was unitized and is presently being waterflooded. Introduction The Rosenwald pool has afforded an excellent opportunity to analyze the performance of a solution gas drive reservoir. This relatively small pool was drilled on 10-acre spacing and had an over-all primary producing life of 41½ years. Care was taken throughout the life of the pool to obtain adequate production and engineering data to enable good comparisons of the actual performance with theoretical concepts.