Effect of Transitions in the Water Table and Soil Moisture Content on the Cathodic Protection of Buried Pipelines

2006 ◽  
Author(s):  
Fraser King ◽  
Russell Given ◽  
Robert G. Worthingham ◽  
Greg Van Boven
Keyword(s):  
Moisture Content ◽  
Water Table ◽  
Cathodic Protection ◽  
Field Measurements ◽  
Field Trials ◽  
High Resistivity ◽  
Buried Pipelines ◽  
Pipe Surface ◽  
Degree Of Protection ◽  
O2 Concentration

Buried pipelines can be subject to transitional environments due to changes in soil type or moisture content. Changes in the height of the water table, for example, will affect not only the availability of water but also the access of oxygen to the pipe surface. Transitions between different soil types will also result in different exposure conditions for different parts of the pipe. These variations can affect the distribution of potential on the pipe surface and the ability of the CP system to provide adequate protection. A combination of laboratory-scale soil box tests and field measurements on operating pipelines has been used to study the effect of varying moisture content and water level on the level of cathodic protection and on pipe-depth environmental conditions. In both laboratory tests and field trials, the degree of protection depends on the availability of cathodic reactants (O2 and/or H2O). Ingress of O2 results in a positive shift in potential as more current is required to electrochemically reduce the oxidant and the pipe is less easily polarized. Under some circumstances the ingress of water has the same effect. Although more aerobic conditions lead to more-positive potentials the pipe is not necessarily less well protected. In many dry and/or high resistivity soils the pipe surface may well be passive because of the high interfacial pH and/or high O2 concentration.

Effect of Transitions in the Water Table and Soil Moisture Content on the Cathodic Protection of Buried Pipelines

2011 ◽  
Vol 133 (1) ◽  
Author(s):  
Fraser King ◽  
Russell Given ◽  
Robert G. Worthingham ◽  
Greg Van Boven
Keyword(s):  
Moisture Content ◽  
Water Table ◽  
Cathodic Protection ◽  
Field Measurements ◽  
Field Trials ◽  
High Resistivity ◽  
Buried Pipelines ◽  
Pipe Surface ◽  
Degree Of Protection ◽  
O2 Concentration

Buried pipelines can be subject to transitional environments due to changes in soil type or moisture content. Changes in the height of the water table, for example, will affect not only the availability of water but also the access of oxygen to the pipe surface. Transitions between different soil types will also result in different exposure conditions for different parts of the pipe. These variations can affect the distribution of potential on the pipe surface and the ability of the CP system to provide adequate protection. A combination of laboratory-scale soil box tests and field measurements on operating pipelines has been used to study the effect of varying moisture content and water level on the level of cathodic protection and on pipe-depth environmental conditions. In both laboratory tests and field trials, the degree of protection was found to depend on the availability of cathodic reactants (O2 and/or H2O). Ingress of O2 results in a positive shift in potential as more current is required to electrochemically reduce the oxidant and the pipe is less easily polarized. Under some circumstances, the ingress of water has the same effect. Although more aerobic conditions lead to more positive potentials, the pipe is not necessarily less well protected. In many dry and/or high resistivity soils, the pipe surface may well be passive because of the high interfacial pH and/or high O2 concentration.

Cathodic Protection in Desert Soils

CORROSION ◽  
1961 ◽  
Vol 17 (12) ◽  
pp. 559t-565t
Author(s):  
W. C. R. WHALLEY
Keyword(s):  
Cathodic Protection ◽  
High Resistivity ◽  
Buried Pipelines ◽  
Pipe Surface ◽  
Desert Soils ◽  
The Matrix ◽  
General Potential ◽  
Arid Desert ◽  
Bare Surface ◽  
Lower Resistivity

Abstract An appraisal is made of special conditions contributing to the severe corrosion experienced on buried pipelines in the arid desert soils of Syria and Iraq. The effectiveness of cathodic protection in reducing corrosion in such areas is discussed in detail. Generally cathodic protection is difficult in desert soils and results are less satisfactory than in moist low resistivity soils. Potentials are notably erratic and are subject to variations of 0.5v within a distance of a few feet. General potential checks at intervals of 200 ft show many points with low potential on pipelines which are polarized (−0.85v or more). In practice the amount of current which can be drained from an element of bare surface is controlled in desert soils by the resistivity of the matrix. Where the bare element is in contact with the high resistivity matrix only, it is possible to drain sufficient current to polarize the pipe surface, provided that the bare element is not too large. Where the bare element is in contact with a lower resistivity salty patch, which is itself enclosed in an envelope of the high resistivity matrix, then it may be a practical impossibility to drain sufficient current through the envelope to polarize the pipe surface. This results in low potential locally. In unfavorable conditions the general polarization of pipe surfaces in desert soils may be very difficult unless the pipe has first class coating surrounded by substantial thickness of soil or selected ditch padding. Even so, areas of locally low potential may exist. 5.2.2, 4.5.2

scholarly journals Effect of Processing on Residual Buprofezin Levels in Ginseng Products

2021 ◽  
Vol 18 (2) ◽  
pp. 471
Author(s):  
Hyun Ho Noh ◽  
Hyeon Woo Shin ◽  
Dong Ju Kim ◽  
Jeong Woo Lee ◽  
Seung Hyeon Jo ◽  
...  
Keyword(s):  
Moisture Content ◽  
Field Trials ◽  
Reduction Factor ◽  
Absolute Amount ◽  
Red Ginseng ◽  
Residual Concentration ◽  
Hot Air ◽  
Practice Gap ◽  
Residue Levels ◽  
Processed Products

This study determined residual buprofezin levels in fresh ginseng and evaluated their changes during processing. Supervised field trials were conducted at Yeongju, Geumsan, and Goesan, Korea. Buprofezin 12.5% EC was applied to 5-y ginseng in accordance with the Korean good agriculture practice (GAP). Samples were collected at 0, 7, 14, 21, and 30 d after the final application. On day 14 (GAP-equivalent preharvest date), the ginseng was processed to obtain dried and red ginseng. The average buprofezin concentrations on day 0 were 0.076 (Yeongju), 0.055 (Geumsan), and 0.078 mg kg−1 (Goesan). Residual concentrations increased as ginseng was processed into dried and red ginseng. Residue levels in dried ginseng manufactured by hot air drying were higher than in red ginseng obtained by steaming, hot air, and sunlight drying. However, the absolute amount of pesticides decreased by approximately 20–30% as a result of calculating the reduction factor considering the dry yield and moisture content. Therefore, the residual concentration in processed products may vary depending on the processing method, and it is deemed necessary to consider the processing yield and moisture content when evaluating the safety of residual pesticides in dried processed products.

Assessment of Moisture Content in Sandy Beach Environments from Multispectral Satellite Imagery

2021 ◽  
Author(s):  
Julie Paprocki ◽  
Nina Stark ◽  
Hans C Graber ◽  
Heidi Wadman ◽  
Jesse E McNinch
Keyword(s):  
Moisture Content ◽  
Laboratory Data ◽  
Field Measurements ◽  
Weather Conditions ◽  
Sandy Beaches ◽  
Percent Error ◽  
Moisture Contents ◽  
Multispectral Satellite Imagery ◽  
Factor C

A framework for estimating moisture content from satellite-based multispectral imagery of sandy beaches was tested under various site conditions and sensors. It utilizes the reflectance of dry soil and an empirical factor c relating reflectance and moisture content for specific sediment. Here, c was derived two ways: first, from in-situ measurements of moisture content and average NIR image reflectance; and second, from laboratory-based measurements of moisture content and spectrometer reflectance. The proposed method was tested at four sandy beaches: Duck, North Carolina, and Cannon Beach, Ocean Cape, and Point Carrew, Yakutat, Alaska. Both measured and estimated moisture content profiles were impacted by site geomorphology. For profiles with uniform slopes, moisture contents ranged from 3.0%-8.0% (Zone 1) and from 8.0%-23.0% (Zone 2). Compared to field measurements, the moisture contents estimated using c calibrated from in-situ and laboratory data resulted in percent error of 3.6%-44.7% and 2.7%-58.6%, respectively. The highest percent error occurred at the transition from Zone 1 to Zone 2. Generally, moisture contents were overestimated in Zone 1 and underestimated in Zone 2, but followed the expected trends based on field measurements. When estimated moisture contents in Zone 1 exceeded 10%, surface roughness, debris, geomorphology, and weather conditions were considered.

scholarly journals A Study on Factors Influencing the Determination of Moisture Content of Fibrous Peat

2011 ◽  
Vol 2 (2) ◽  
pp. 39-47 ◽  
Author(s):  
Pui Tau Shien ◽  
Seneviratne H.N. ◽  
Dygku Salma Awg Ismail
Keyword(s):  
Moisture Content ◽  
Particle Density ◽  
Peat Soil ◽  
Test Procedure ◽  
Field Measurements ◽  
Standard Test ◽  
Moisture Loss ◽  
Fibrous Peat ◽  
Saturated Sample

Fibrous peat is an undrained peat that usually possesses very high moisture content. However, not all experimental procedures are applicable for determination of moisture content of fibrous peat. This research is aimed at examining the determination of insitu moisture content of fibrous peat using field measurements. The peat soil samples were collected at shallow depths from Asajaya at Kota Samarahan and Taman Kopodims at Matang , Kuching Sarawak by using peat auger. The laboratory tests such as determination of moisture content, fiber content, particle density and ash content were conducted on the collected samples in order to establish relationships between the parameters. Undisturbed peat samples from Matang were subjected to falling head permeability test to determine the saturated permeability. The saturated sample were then allowed to drain freely to simulate the moisture loss possible during sampling when samples were brought out of boreholes. The test results showed that moisture content varies according to the drying temperature and position of the soil sample (top, middle and bottom) during sampling. Comparing samples from both locations, peat soil from Kota Samarahan possessed higher moisture content. The saturated permeability of peat sample was in the range of 2.62 – 3.05 cm/s. The free draining trial showed that moisture loss during sampling significantly influence the moisture content measurement. The variation in value of moisture content for fibrous peat may occurs due to several factors such as existing ground water table, sampling method by boring, existing standard test procedure which is not suitable for peat soils requirement and also because of the physical properties which varied according to depth of soil.

scholarly journals Development of an analytical model to predict oil reservoirs performance using mechanical waves propagation

2021 ◽  
Author(s):  
Hesham A. Abu Zaid ◽  
◽  
Sherif A. Akl ◽  
Mahmoud Abu El Ela ◽  
Ahmed El-Banbi ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Field Measurements ◽  
Field Trials ◽  
Oil Field ◽  
Reservoir Properties ◽  
Actual Performance ◽  
Reservoir Performance ◽  
Mechanical Waves ◽  
Incremental Oil Recovery ◽  
Wave Induced

The mechanical waves have been used as an unconventional enhanced oil recovery technique. It has been tested in many laboratory experiments as well as several field trials. This paper presents a robust forecasting model that can be used as an effective tool to predict the reservoir performance while applying seismic EOR technique. This model is developed by extending the wave induced fluid flow theory to account for the change in the reservoir characteristics as a result of wave application. A MATLAB program was developed based on the modified theory. The wave’s intensity, pressure, and energy dissipation spatial distributions are calculated. The portion of energy converted into thermal energy in the reservoir is assessed. The changes in reservoir properties due to temperature and pressure changes are considered. The incremental oil recovery and reduction in water production as a result of wave application are then calculated. The developed model was validated against actual performance of Liaohe oil field. The model results show that the wave application increases oil production from 33 to 47 ton/day and decreases water-oil ratio from 68 to 48%, which is close to the field measurements. A parametric analysis is performed to identify the important parameters that affect reservoir performance under seismic EOR. In addition, the study determines the optimum ranges of reservoir properties where this technique is most beneficial.

scholarly journals Spatial and temporal variation of methane emissions in drained eutrophic peat agro-ecosystems: drainage ditches as emission hotspots

2008 ◽  
Vol 5 (2) ◽  
pp. 1237-1261 ◽  
Author(s):  
A. P. Schrier-Uijl ◽  
E. M. Veenendaal ◽  
P. A. Leffelaar ◽  
J. C. van Huissteden ◽  
F. Berendse
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Table ◽  
Soil Moisture Content ◽  
Explanatory Variable ◽  
Spatial And Temporal Variation ◽  
Spatial And Temporal Variability ◽  
Ch4 Emissions ◽  
Intensively Managed ◽  
Moisture Conditions

Abstract. Our research investigates the spatial and temporal variability of methane (CH4) emissions in two drained eutrophic peat areas (one intensively managed and the other less intensively managed) and the correlation between CH4 emissions and soil temperature, air temperature, soil moisture content and water table. We stratified the landscape into landscape elements that represent different conditions in terms of topography and therefore differ in moisture conditions. There was great spatial variability in the fluxes in both areas; the ditches and ditch edges (together 27% of the landscape) were methane hotspots whereas the dry fields had the smallest fluxes. In the intensively managed site the fluxes were significantly higher by comparison with the less intensively managed site. In all the landscape element elements the best explanatory variable for CH4 emission was temperature. Neither soil moisture content nor water table correlated significantly with CH4 emissions, except in April, where soil moisture was the best explanatory variable.

scholarly journals Performance of Global Atmospheric Datasets towards Groundwater Management

10.29007/5swr ◽  
2018 ◽  
Author(s):  
Paolina Bongioannini Cerlini ◽  
Silvia Meniconi ◽  
Bruno Brunone
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Groundwater Management ◽  
Water Flow ◽  
Water Table ◽  
Soil Moisture Content ◽  
Weather Forecasts ◽  
Reliable Tool ◽  
Umbria Region ◽  
Medium Range

With the aim of refining a reliable tool for groundwater management, the ERA-Interim and ERA5 global atmospheric datasets provided by the European Centre for Medium- Range Weather Forecasts (ECMWF) are examined. Attention is focused on the analysis of the behavior of the soil moisture content. The performance of ERA-Interim and ERA5 is evaluated by considering the water table measurements at three sites in the Umbria region as well as the dynamics of water flow towards the groundwater.

Tar-Polyurethane Joint Coating for the Three-Layer Polyethylene Pipeline Coating

1996 ◽  
Author(s):  
Robert H. Rogers
Keyword(s):  
Cathodic Protection ◽  
Surface Preparation ◽  
Spray Coating ◽  
Field Trials ◽  
Localized Corrosion ◽  
Preparation Technique ◽  
Coating System ◽  
Actual Field ◽  
History Of Use ◽  
Key Steps

This article describes a new joint coating system implemented by Bechtel for a major international, 48 inch diameter gas pipeline. Despite the long history of use as a pipe and valve coating, the new implementation is the industry’s first significant use of a thermoset hot spray coating applied to field weld areas of pipe, mill coated with a three layer polyethylene system. In the laboratory and in field trials, the coating demonstrated integrity, was applied much quicker than the traditional heat shrink sleeve, and eliminated several application contingencies. Laboratory investigations undertaken in Houston, Texas and Lyon, France were key steps in selecting the 100% solids tar-polyurethane coating. Additionally, the testing assisted in developing the surface preparation technique, and demonstrating the coating’s ability to adhere to the polyethylene coating as well as the steel pipe. Serious localized corrosion, and cathodic protection shielding associated with other joint coatings are less probable with the new joint coating system. Actual field cathodic protection testing indicated very low current consumption for the completed pipeline. The efficient joint coating operation contributed to setting new construction records.

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