On the effects of thermal properties structure and water bottom temperature variation on temperature gradients in lake sediments

1986 ◽  
Vol 23 (9) ◽  
pp. 1257-1264 ◽  
Author(s):  
K. Wang ◽  
P. Y. Shen ◽  
A. E. Beck
Keyword(s):  
Heat Flow ◽  
Temperature Variation ◽  
Stratified Medium ◽  
Depth Interval ◽  
Flow Density ◽  
Detailed Knowledge ◽  
Bottom Temperature ◽  
Temperature Variations ◽  
Density Values ◽  
Finite Sum

In heat flow determinations, it is customary to treat the surface temperature variation as a finite sum of Fourier components. The medium is assumed to be homogeneous or horizontally stratified with each layer having a constant conductivity and diffusivity. This allows the effect of each periodic component to be calculated analytically. We extend this formulation to include cases where thermal conductivities in some layers of a stratified medium may vary linearly with depth as have been found in the sediments of some continental lakes. The application of this formalism to temperature measurements in Lake Greifensee and Lac Leman shows that even with excellent records of bottom temperature variations over several years, failure to take into account the conductivity variation leads to errors as high as 20% in heat flow density values, depending on the depth interval used. The combined effects of lack of detailed knowledge of conductivity structure and the use of too short and (or) inaccurate records of bottom temperature variations, leading to very significant errors, are also discussed, with particular reference to the problems arising from a lack of recognition of the existence of nonannual terms in the bottom temperature variation and the use of probes that do not penetrate the sediments deeply enough.

scholarly journals Summary of heat flow studies in Nigeria

2019 ◽  
pp. 121-132
Author(s):  
Vladimir I. Zui ◽  
Lukman Akinyemi
Keyword(s):  
Magnetic Field ◽  
Heat Flow ◽  
Heat Conductivity ◽  
Traditional Approach ◽  
Geothermal Gradient ◽  
Depth Interval ◽  
Flow Density ◽  
Flow Data ◽  
Heat Flow Density ◽  
Two Parameters

A traditional approach for heat flow determination requires two parameters. They are a geothermal gradient and heat conductivity of rocks comprising the considered depth interval. The geothermal gradient is determined from a thermogram recorded in a wellbore and the heat conductivity is obtained from the laboratory measurements of selected rock samp les. There are some variations of this approach to both get the gradient and heat conductivity values. However, there are many areas without boreholes to register their thermograms, or at least to have several temperature readings at intermediate positions of bottom holes and traditional methods of heat flow determinations cannot be used. Recently another method was proposed to estimate heat flow. It was derived from spectral analysis of magnetic field. During last years it was widely used in Nigeria for areas where deep boreholes are absent. It uses estimates of depths to the base and bottom of the causative body derived from analysis of the magnetic field maps. The base of the causative body corres ponds to the depth of the Curie surface at which rocks lose their magnetic properties. It is known that it happens at the temperature around 580 °C that slightly varies depending on the content of magnetite within the causative body. The temperature at the top of this body is estimated. The heat flow density can be calculated knowing the geothermal gradient within this depth interval and heat conductivity of rocks. A preliminary heat flow density map was compiled based on all accessible heat flow data. A comparison of heat flow data from several regions of the country, determined using both methods provides rather good agreement.

scholarly journals Using Heat Flow Density Values Obtained in the Gulf of Cadiz and Gorringe Bank, Atlantic Ocean

2021 ◽  
Vol 906 (1) ◽  
pp. 012113
Author(s):  
Maria Rosa Duque
Keyword(s):  
Heat Flow ◽  
Atlantic Ocean ◽  
Geoid Height ◽  
Moho Depth ◽  
Flow Density ◽  
Heat Sources ◽  
Heat Flow Density ◽  
A Value ◽  
Density Values ◽  
Lithosphere Thickness

Abstract The geothermal heat flow measured at the surface of the Earth is originated by different heat sources located at different depths of the planet. The main sources of heat flow in the crust are associated with radioactive decay of Uranium, Thorium and Potassium, in rocks. In some regions, additional heat sources must be considered such as exothermic chemical reactions. The value of the heat flow coming from deep regions, designated by “heat from the mantle”, must be obtained using indirect methods. In this work, the geoid height was used as indicator of alterations “in heat from the mantle” values, considering that the density decrease in regions with geoid height increase is related to high temperature values in the upper part of the mantle. The region on study is located in the Atlantic Ocean, SW of Cape St. Vincent and Cadiz Gulf. Temperature-depth values were obtained in twelve points of the region considering heat flow by conduction in the vertical direction, using published heat flow and thermal conductivity data. Layered models were made using data obtained in published seismic profiles. Moho depth values were used as lower boundary of the crust and mantle heat flow variations were made according geoid height increases. Ocean depth values between 2.5 and 4.3 km were used. A value of 5°C was used for temperature at the upper boundary (ocean bottom) of the models. Temperature calculus stops when a value of 1350 °C was attained. Lithosphere thickness is obtained considering this temperature value as temperature at the bottom of the lithosphere. Heat flow density values from 36 to 65.8 mW m−2 were used in the work with “heat from the mantle” values from 33 to 35 mw m−2. Curie Point Temperature (600°C) depths from 33 to 36 km were obtained. Lithosphere thickness values about 97 km were obtained in all the models.

Preliminary heat-flow density data from Tunisia and the Pelagian Sea

1989 ◽  
Vol 26 (5) ◽  
pp. 993-1000 ◽  
Author(s):  
Francis Lucazeau ◽  
Hammed Ben Dhia
Keyword(s):  
Heat Flow ◽  
Structural Evolution ◽  
Flow Density ◽  
Heat Flow Density ◽  
Density Data ◽  
Geophysical Logs ◽  
Density Values ◽  
Cooling Effects ◽  
Temperature Records ◽  
Actual Formation

Heat-flow density values at 78 sites in Tunisia and the Pelagian Sea are derived from oil exploration wells. Bottom-hole temperatures (BHT) are systematically corrected for mud circulation cooling effects either by a Horner technique when several temperature records are available at a given depth or by a statistical method based on the comparison of all BHT with test temperatures (DST) that are representative of the actual formation temperatures. Thermal conductivities are estimated from detailed studies of stratigraphic and geophysical logs. An inverse technique is used to estimate heat-flow density for each borehole, as well as interpolated temperatures at constant depths. Results are discussed with maps that include heat-flow density data in neighbouring areas (Algeria and the Strait of Sicily). The general trend corresponds remarkably to the recent structural evolution of the Tunisian margin with high values in the Pelagian Sea and decreasing values toward the stable platform.

scholarly journals OIL AND GAS MODELING GENERARION IN THE JURASSIC SEDIMENTS IN THE SOUTH-EASTERN OF THE WEST SIBERIAN PETROLEUM PROVINSE

2021 ◽  
Vol 2 (1) ◽  
pp. 38-43
Author(s):  
Elena A. Glukhova ◽  
Pavel I. Safronov ◽  
Lev M. Burshtein
Keyword(s):  
Heat Flow ◽  
Thermal History ◽  
Oil And Gas ◽  
Flow Density ◽  
Basin Modeling ◽  
Heat Flow Density ◽  
The West ◽  
One Dimensional ◽  
History Of ◽  
The One

The article presents the one-dimensional basin modeling performed in four wells to reconstruct the thermal history of deposits and reconstruct the effective values of the heat flow density.

scholarly journals Heat flow and presence of oil and gas (the Yamal peninsula, Tomsk region)

Georesursy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 125-135
Author(s):  
Valery I. Isaev ◽  
Galina A. Lobova ◽  
Alexander N. Fomin ◽  
Valery I. Bulatov ◽  
Stanislav G. Kuzmenkov ◽  
...  
Keyword(s):  
Heat Flow ◽  
Western Siberia ◽  
Oil And Gas ◽  
Sedimentary Cover ◽  
The Arctic ◽  
Yamal Peninsula ◽  
Flow Density ◽  
Positive Anomaly ◽  
Tomsk Region ◽  
History Of

The possibilities of Geothermy as a geophysical method are studied to solve forecast and prospecting problems of Petroleum Geology of the Arctic regions and the Paleozoic of Western Siberia. Deep heat flow of Yamal fields, whose oil and gas potential is associated with the Jurassic-Cretaceous formations, and the fields of Tomsk Region, whose geological section contents deposits in the Paleozoic, is studied. The method of paleotemperature modeling was used to calculate the heat flow density from the base of a sedimentary section (by solving the inverse problem of Geothermy). The schematization and mapping of the heat flow were performed, taking into account experimental determinations of the parameter. Besides, the correlation of heat flow features with the localization of deposits was revealed. The conceptual and factual basis of research includes the tectonosedimentary history of sedimentary cover, the Mesozoic-Cenozoic climatic temperature course and the history of cryogenic processes, as well as lithologic and stratigraphic description of the section, results of well testing, thermometry and vitrinite reflectivity data of 20 deep wells of Yamal and 37 wells of Ostanino group of fields of Tomsk region. It was stated that 80 % of known Yamal deposits correlate with anomalous features of the heat flow. Bovanenkovskoe and Arkticheskoe fields are located in positive anomaly zones. 75 % of fields of Ostanino group relate to anomalous features of the heat flow. It is shown that the fields, which are characterized by existence of commercial deposits in the Paleozoic, are associated with the bright gradient zone of the heat flow. The forecast of commercial inflows in the Paleozoic for Pindzhinskoe, Mirnoe and Rybalnoe fields is given. The correlation between the intensity of naftidogenesis and the lateral inhomogeneity of the deep heat flow is characterized as a probable fundamental pattern for Western Siberia.

scholarly journals Heat Flow, Geotherms, Density and Lithosphere Thickness in SW of Iberia (South of Portugal)

2018 ◽  
Vol 1 (1) ◽  
pp. 18-22 ◽  
Author(s):  
Maria Rosa Alves Duque
Keyword(s):  
Heat Flow ◽  
Thermal Structure ◽  
Average Density ◽  
Ore Deposits ◽  
Flow Density ◽  
The South ◽  
Lithosphere Thickness ◽  
Structure Density ◽  
Using Data ◽  
Lateral Variations

Thermal structure, density distribution and lithosphere thickness in the SW part of the Iberian Peninsula are studied using data obtained in the South Portuguese Zone (SPZ) and SW border of the Ossa Morena Zone (OMZ) in the South of Portugal. Five different regions were defined, and models were built for each region. Geotherms were obtained using average density values from data published. The high values of heat flow density in these regions are attributed to occurrence of anomalous heat sources due to radioactivity content and exothermic chemical reactions associated to ore deposits in the zone. The results obtained with models based on isostasy in the region led to lithosphere thickness values between 95 and 96 km in the SPZ and a lower value of 94.5 km in the SW border of the OMZ. Analysis of geotherms shows lateral variations of temperature at the same depth. These lateral variations are compared with information obtained with seismic data.

scholarly journals Geothermal field and geology of the Caspian Sea region

2019 ◽  
pp. 104-118 ◽  
Author(s):  
Vladimir I. Zui ◽  
Siamak Mansouri Far Far
Keyword(s):  
Heat Flow ◽  
Flow Pattern ◽  
Caspian Sea ◽  
Sedimentary Basins ◽  
Geothermal Field ◽  
Flow Density ◽  
General Tendency ◽  
The Caspian Sea ◽  
Northern Iran ◽  
The North

The Caspian Sea and adjacent areas form the vast oil and gas-bearing megabasin. It consists of North Caspian, Middle Caspian, and South Caspian sedimentary basins. The granite-metamorphic basement of the basins becomes from north to south younger in the direction from Early Precambrian to Early Cimmerian age. It represents a transitional zone from the southern edge of the East European Craton to Alpine folding. Geothermal investigations have been carried out both in hundreds of deep boreholes and within the Caspian Sea and a few preliminary heat flow maps were published for the Caspian Sea region. All they excluded from consideration the southern part of the region within Iranian national borders. We prepared a new heat flow map including the northern Iran. The purpose of the article is to consider heat flow pattern within the whole Caspian Sea region including its southern part. Two vast high heat flow anomalies above 100 mW/m2 distinguished in the map: within the southwestern Iran and in waters of the Caspian Sea to the North of the Apsheron Ridge, separated by elongated strip of heat flow below 50 –55 mW/m 2 . A general tendency of heat flow from growing was distinguished from the Precambrian crustal blocks of the North Caspian Depression to the Alpine folding within the territory of Iran. Analysis of the heat flow pattern is discussed and two heat flow density profiles were compiled.

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