An ultrasonic testing method employing the pulse-echo inspection technique was developed to assess the integrity of annular seals surrounding casings (i.e.. instrument tubes or well casings). This nondestructive testing method permits testing aseal from inside acasing without disturbing the casing, seal. or formation. Seals constructed with cement-based and bentonite-based sealants surrounding ...

Fipronil insecticide dissipated in California rice fields, producing half-lives of 10.5 to 125 h in water and 44.5 to 533 h in soil, depending on the formulation applied and the resulting differences in water solubility. The major degradation products were desthiofipronil in water and fipronil-sulfide in soil, while the sulfone and amide were less abundant. Fipronil was photolyzed rapidly to de...

The goal of the study was to apply and modify the semiemperical water-cloud model to simulate bacscattering coefficients of C-VV and L-HH as a function of LAI, vegetation water content and soil moisture. Bacscattering coefficients were compared to these obtained from ERS-2.SAR and JERS.SAR measurements taken simultaneously for the agriculture area in Poland. During time of satellite acquisition...

With the unceasing exploitation of gas fields, casing damage is an important element which restrict oil-gas throughput. In this paper we present an distributed optical fiber Bragg grating analysical method in the Real-time Casing Damage Monitoring Work which through the study of the main type and damage of casing damage, analysis and comparison of the casing damage monitoring method, responding...

Polarimetric Xand C-band measurements by the University of Sheffield ground-based synthetic aperture radar (GB-SAR) indoor system provide three-dimensional images of the scattering processes in wheat canopies, at resolutions of around a wavelength (3–6 cm). The scattering shows a pronounced layered structure, with strong returns from the soil and the flag leaves, and in some cases a second leaf...

This paper illustrates some results obtained in the frame of an experimental campaign carried out on several wheat fields of the Matera (Italy) site, from February 2003 to June 2004. During this period, ENVISAT ASAR data, at alternating polarization mode and at different incidence angles, were acquired on the area roughly every week. Ground data such as soil moisture content, wheat biomass, LAI...

A change detection algorithm is applied on a three year time series of ASAR Wide Swath images in VV polarization over Calabria, Italy, in order to derive information on temporal soil moisture dynamics. The algorithm, adapted from an algorithm originally developed for ERS scatterometer, was validated using a simple hydrological model incorporating meteorological and pedological data. Strong posi...

Based on the propagation rules of electromagnetic waves in metal conductors, this paper analyzes the characteristics of electric field and magnetic field of internal conductors. Then the complex power of electromagnetic wave is calculated. The impedance calculation formula of metal conductor is derived. Moreover, in order to identify and detect defects of metal casing, an alternating current im...

A good knowledge of the parameters causing casing damage is critically important due to vital role of casing during the life of a well. Cement sheath, which fills in the gap between the casing and wellbore wall, has a profound effect on the resistance of the casing against applied loads. Most of the empirical equations proposed to estimate the collapse resistance of casing ignore the effects of...

26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 An experimental study based on the effects of fire on soil hydrology was developed at the Experimental Station of “La Concordia” (Valencia, Spain). It is located on a calcareous hillside facing SSE and composed of nine erosion plots (4 x 20 m). In summer 2003, after eight years of soil and vegetation recovery from previo...