Effect Of Structural Deformation Research Articles

Anschutz Ranch East--Finding and Defining a Giant Oil Field in Thrust Belt: ABSTRACT

Anschutz Ranch East is the giant oil field of the western United States thrust belt, with over 3/4 billion bbl of oil equivalent in place. The original prospect was not so impressive. Extensive Tertiary cover precluded precise prospecting by surface mapping. An early well penetration of a shallow recumbent fold tied to conventional 2-D seismic reflection lines hinted at a Triassic-Jurassic structure 1,500 acres (600 ha.) in extent. Soon after Amoco discovered Anschutz Ranch East in 1979, production pressure data revealed that the field was very large; but it was development drilling and 3-D seismic that prompted the geologic interpretation of 14,600 acres (5,900 ha.) under closure. Still being delineated nearly 5 yr after its discovery, the current size estimate is near 4 000 acres (1,600 ha.). The field, therefore, serves as a good case example of the difficulties involved in geologic mapping using remote data. Anschutz Ranch East is part of a prolific oil trend extending more than 40 mi (64 km) along the leading edge of a major regional thrust plate. Situated in the extreme southwest corner of Wyoming and adjacent Utah, the field produces from separate reservoirs in two en echelon structures. The more significant west lobe is a highly overturned, narrow anticline with more than 2,000 ft (610 m) of hydrocarbon column. The producing Triassic-Jurassic Nugget Sandstone, largely eolian in origin, is just over 1,000 ft (305 m) thick, with more than 75% of the rock capable of contributing to production. Geologically, the field has passed through several stages of geometric interpretation: the faulted stage, the concentric fold stage, and the angular stage. Development of these three interpretation was based largely on outcrop examples of fold geometries in thrust belts of both the eastern and western United States. Production rates in the first half of 1984 averaged approximately 36,000 bbl of condensate, 6,500 bbl of natural gas liquid, and 215 mmcf of gas per day. The reservoir fluid is a rich gas condensate originally about 150 psi (1,034 kPa) above the dew-point pressure. Complexities involving reservoir fluid properties, stratigraphic influences on fluid flow, effects of structural deformation, and fracture systems have required close cooperation between geologists and reservoir engineers in planning for field development. With this cooperation to maximize recovery, the recovery factor for hydrocarbons in place is expected to be about 70%. More than 90% of the field's recovery will come from the west structure, which is just over 1 mi (1.6 km) wide and probably less than 6 mi (9.7 km) long. Fields of this size might be easily missed in thrust belt exploration. End_of_Article - Last_Page 1837------------

Distribution functions and mutual effect of structural deformations in steel 1Kh2M subjected to tension at elevated temperatures

1. The distribution of structural deformations measured on a base of 10 and 20 μm for steel 1Kh2M with a grain size approaching 20 μm is characterized by the normal law over the entire temperature interval investigated (20–700 °C). 2. The dimensions of the region of the mutual effect of microvolumes as determined from the behavior of the autocorrelation function of structural deformations diminish with test temperature; this is accompanied by activation of the mechanism of intergranular deformation.

Projectile perforation of multi-layered beams

A combined analytical and experimental study has been performed on the ballistic resistance of layered targets, in particular of flat, relatively thin beams with clamped ends in spaced and laminated (i.e. in contact without bonding) conditions. The theoretical analysis combines the effect of structural deformation with the mechanism of perforation. This requires a redefinition of the ballistic limit velocity as the initial impact velocity for which the post perforation velocity and the structural deformation velocity of the impact point would be equal at the same time. The ballistic tests were based on commercially pure and alloy (6061-T6) aluminum target specimens of various thicknesses and configurations, and used 0·22 in. caliber projectiles which struck the targets perpendicularly at their center with a velocity of 375 msec. The results for the velocity drop show fairly good agreement between experiments and predictions, and greater ballistic resistance of the laminated configuration.

Nonlinear Effects of Structural Deformation on Stability

An analysis is made of the effect of skin buckling on longitudinal stability and the influence of such effect on control forces. Buckling alters aeroelastic characteristics by the reduction of torsional rigidity in the case of an unswept wing and by the reduction of both bending and torsional rigidity in the case of a swept wing. I t can also precipitate flow separation, which affects pitching moments. Since buckling commonly occurs under the higher load factor conditions, large changes in the slope of the lines of stick force versus load factor may be the consequence. The flow separation appears to have the predominant influence on such slope changes. Test data of a current fighter airplane are used for illustration. Mention is made of the effect of a variable modulus of elasticity on the rate of structural deformation and of the effect of bending deflection on the camber of a swept-wing section.