Understanding the regional migration routes and field charging history of the Oued Mya-Hassi Messaoud petroleum system, Algeria

PhD ThesisThis thesis describes a detailed geochemical evaluation of the Oued Mya-Hassi Messaoud ridge petroleum system, located in the central Sahara-Algeria. The study area consists of several fields: (1) the Devonian and the Lower Triassic fields located in the Oued Mya basin which are generally small and in direct contact with the Silurian source rock in the basin, (2) the broad low-relief structural traps developed in the Cambro-Ordovician quartzite reservoirs on the adjoining El-Agreb-Hassi Messaoud ridge, 50 to 60 km east of the Oued Mya basin. Utilising conventional biomarker facies and maturity parameters and aromatic hydrocarbons, it is shown that all the oils from the Devonian, the Lower Triassic and the Cambrian fields across the whole petroleum system are similar to the Silurian source rock strata which are widely recognised to be the main source in the region. The oils in the study area are discriminated into three main groups; I) oils from the Hassi Messaoud, Hassi Guettar and El-Agreb fields located in the Hassi Messaoud ridge, II) oils from the Devonian and the Lower Triassic fields located in the Oued Mya basin and III) oils from El-Baguel and Mesdar Cambrian fields. The oils from the El-Baguel and Mesdar Cambrian fields are believed to be generated from the Silurian source rocks located in the Berkine basin, east of the Hassi Messaoud ridge. The biomarker and aromatic hydrocarbon maturity parameters as well as the pyrrolic nitrogen compounds (alkylcarbazoles and benzocarbazoles) data suggest that the oils from Mokh-El-Kebch, N'goussa, Guellala northeast, Guellala and Draa Temra Triassic fields have undergone the least migration distances and were predominantly charged vertically from the underlying Silurian source rocks which are in direct contact with the Devonian and the Lower Triassic reservoirs. The oils from the Haoud Berkaoui and the Benkahla fields appear to have experienced both vertical followed by lateral migration (probably —20 km). Charging of the Hassi Messdoud reservoirs occurred predominantly from the west-northwest and east sectors. The oil experienced long lateral migration distances (40-60 km) starting from the Silurian source rock strata in the northeast of the Oued Mya basin and the Silurian source rock strata located around the Dzabat area east of the field. Once in the Hassi Messaoud reservoirs, the oil migrated upwards towards the crest located in the centre, then downwards to the north, south and finally west parts of the field. Charging of the Hassi Guettar and El-Agreb fields occurred from the north (i.e. from the Hassi Messaoud field). It seems that El-Agreb oils have experienced the longest migration distances across the whole petroleum system (120 to 140 km). Finally, the charging of the Mesdar and El-Baguel fields took place laterally from the southsoutheast starting from the Silurian source likely located in the Berkine basin east of the Hassi Messaoud ridge. The oil in the El-Baguel field seems to have experienced longer migration distance then the oil from the Mesdar field. The study of the petroleum fluid inclusions in the Hassi Messaoud field revealed a reasonable model of temperature and charge history of the Hassi Messaoud field. The modelling results suggest that the Hassi Messaoud sandstone member was at a depth of 2.8 to 3.3 km during the time of petroleum migration into the reservoirs and petroleum inclusion formation. The temperature range at this depth was between 106°C to 118°C from Late Cretaceous to Palaeogene. The distribution of biomarkers and aromatic hydrocarbons in the palaeo-oils extracted from the petroleum inclusions in 6 samples from Hassi Messaoud field and 1 sample from Haoud Berkaoui field revealed that: (1) the palaeo-oils trapped in petroleum inclusions of both fields and the present-day produced oils are similar, likely generated from the Silurian, main source rocks in the region; (2) the palaeo-oils are less mature than the present-day produced oils; and (3) the palaeo-oil trapped in the Haoud Berkaoui Triassic reservoir is even less mature than the palaeo-oils trapped in the Hassi Messaoud reservoirs which may suggest an earlier oil charging of the Haoud Berkaoui field compared to the charging of the Hassi Messaoud field.Sonatrach-BP-Amoco

Understanding the regional migration routes and field charging history of the Oued Mya-Hassi Messaoud petroleum system, Algeria

PhD ThesisThis thesis describes a detailed geochemical evaluation of the Oued Mya-Hassi Messaoud ridge petroleum system, located in the central Sahara-Algeria. The study area consists of several fields: (1) the Devonian and the Lower Triassic fields located in the Oued Mya basin which are generally small and in direct contact with the Silurian source rock in the basin, (2) the broad low-relief structural traps developed in the Cambro-Ordovician quartzite reservoirs on the adjoining El-Agreb-Hassi Messaoud ridge, 50 to 60 km east of the Oued Mya basin. Utilising conventional biomarker facies and maturity parameters and aromatic hydrocarbons, it is shown that all the oils from the Devonian, the Lower Triassic and the Cambrian fields across the whole petroleum system are similar to the Silurian source rock strata which are widely recognised to be the main source in the region. The oils in the study area are discriminated into three main groups; I) oils from the Hassi Messaoud, Hassi Guettar and El-Agreb fields located in the Hassi Messaoud ridge, II) oils from the Devonian and the Lower Triassic fields located in the Oued Mya basin and III) oils from El-Baguel and Mesdar Cambrian fields. The oils from the El-Baguel and Mesdar Cambrian fields are believed to be generated from the Silurian source rocks located in the Berkine basin, east of the Hassi Messaoud ridge. The biomarker and aromatic hydrocarbon maturity parameters as well as the pyrrolic nitrogen compounds (alkylcarbazoles and benzocarbazoles) data suggest that the oils from Mokh-El-Kebch, N'goussa, Guellala northeast, Guellala and Draa Temra Triassic fields have undergone the least migration distances and were predominantly charged vertically from the underlying Silurian source rocks which are in direct contact with the Devonian and the Lower Triassic reservoirs. The oils from the Haoud Berkaoui and the Benkahla fields appear to have experienced both vertical followed by lateral migration (probably —20 km). Charging of the Hassi Messdoud reservoirs occurred predominantly from the west-northwest and east sectors. The oil experienced long lateral migration distances (40-60 km) starting from the Silurian source rock strata in the northeast of the Oued Mya basin and the Silurian source rock strata located around the Dzabat area east of the field. Once in the Hassi Messaoud reservoirs, the oil migrated upwards towards the crest located in the centre, then downwards to the north, south and finally west parts of the field. Charging of the Hassi Guettar and El-Agreb fields occurred from the north (i.e. from the Hassi Messaoud field). It seems that El-Agreb oils have experienced the longest migration distances across the whole petroleum system (120 to 140 km). Finally, the charging of the Mesdar and El-Baguel fields took place laterally from the southsoutheast starting from the Silurian source likely located in the Berkine basin east of the Hassi Messaoud ridge. The oil in the El-Baguel field seems to have experienced longer migration distance then the oil from the Mesdar field. The study of the petroleum fluid inclusions in the Hassi Messaoud field revealed a reasonable model of temperature and charge history of the Hassi Messaoud field. The modelling results suggest that the Hassi Messaoud sandstone member was at a depth of 2.8 to 3.3 km during the time of petroleum migration into the reservoirs and petroleum inclusion formation. The temperature range at this depth was between 106°C to 118°C from Late Cretaceous to Palaeogene. The distribution of biomarkers and aromatic hydrocarbons in the palaeo-oils extracted from the petroleum inclusions in 6 samples from Hassi Messaoud field and 1 sample from Haoud Berkaoui field revealed that: (1) the palaeo-oils trapped in petroleum inclusions of both fields and the present-day produced oils are similar, likely generated from the Silurian, main source rocks in the region; (2) the palaeo-oils are less mature than the present-day produced oils; and (3) the palaeo-oil trapped in the Haoud Berkaoui Triassic reservoir is even less mature than the palaeo-oils trapped in the Hassi Messaoud reservoirs which may suggest an earlier oil charging of the Haoud Berkaoui field compared to the charging of the Hassi Messaoud field.Sonatrach-BP-Amoco

Irrigation Water Impact on Soil Properties in Arid Oued-Souf Region, Southeast Algeria

The perimeters of the Oued-Souf region are irrigated by salty water coming from the phreatic water and thus progressive salinization of the soil occurs. This study aims at a qualitative analysis of the evolution of the salinity in the soils irrigated by pivot irrigation for several years. For this, three plots were irrigated by pivots in each agricultural region. The choice of these 3 plots is justified by the number of years of their cultivation: plot 1 has been cultivated and irrigated for 2 years (2016–2017), plot 2 has been cultivated and irrigated for 5 years (2016– 2020) were studied and compared to the controlled soil not irrigated. The irrigation is done by sprinkling with mineralized water from the phreatic water. The results obtained showed that the irrigation water is characterized by high salinity and low sodium adsorption ration (SAR). Sodium and chloride contents are excessive in sprinkler irrigation mode. The evolution of salinity in irrigated soils between 2 and 5 years was very significant compared to the control (non-irrigated). The salinity goes from 0.38 dS/m in the control site classified as low salinity to 1.54 dS/m in the cultivated site for the 5 years classified as high salinity soil. The geochemical facies at the three study regions after irrigation are sulfate-calcium. A significant correlation is observed between calcium and sulfate with electrical conductivity (EC), so the salinity of our soils is dominated by sulfate. These results are confirmed by statistical analysis of the data (PCA), which revealed that salinity is heavily influenced by Mg2+, Ca2+, SO42- in the topsoil

OVERALL WATER LOSSES DURING SPRINKLER IRRIGATION IN ARID AREA:CASE OF TOUGGOURT - ALGERIA

In recent years, the development of agriculture in Algeria Southeast grew rapidly, which increased demand for agricultural products. Since this region has difficult agro-climatic conditions, irrigation seems to be a necessary factor to ensure optimal development and higher agricultural production. Like many irrigation techniques that are widely used, the performance of sprinkler irrigation is significantly affected by these conditions (mainly evaporation) which cause colossal water losses. The purpose of this study is to evaluate, through the experimental approach, the global losses of water caused by evaporation and wind drift on two irrigated surfaces in the arid zone of Touggourt. Here we propose adequate predictive equations and explore the effect of irrigated area on overall water loss values. These are measured on two blocks (A and B) the rain gauge method. Block A contains four lateral lines while Block B has only two. For both, each lateral line has four sprinklers. The results showed that the overall water losses of block A are about 24.13 to 50.46%, while those of Block B range from 29.52 to 49.5 %.Two obtained models are adopted for both blocks which can be useful tools for determining overall water losses in environmental conditions (air temperature, relative humidity and wind speed).Noting that when the irrigated area was larger, the water losses will be lass

Erratum to: Comparative assessment between GR model and tank model for rainfall-runoff analysis using Kalman filterapplication to Algerian basins-.

Modeling the rainfall-runoff relationship with conceptual models has always been a fascinating subject for hydrologists in view of its practical importance and complexity. This study presents a comparative assessment of the performance of two well established rainfall-runoff conceptual models. A first model called: Model ‘Genie Rural’ (i.e. Agricultural Engineering) and abbreviated GR, developed by Cemagref has been extensively tested in the Mediterranean watersheds and some basins in African countries. When applied to Algerian basins, the different version of the GR model gave satisfactory results, particularly for long time steps (monthly and annual data). In this work, the tank Model by Sugawara using Kalman filter for adaptive calibration is developed and tested for the first time to assess rainfall-runoff in Algerian basins. The results appear to be very prominent and far better than those given by the GR models including daily time steps. Indeed, a comparison between the two models established for daily and monthly data was performed on the three (03) Algerian Basins (i.e. Isser, Zardezas basin and Cheffia). Calibration of the Tank model parameters was performed by Kalman filter. Furthermore, the structure of tank model (i.e: number of tanks, number of outlets in each tank, and their location) was determinated for the studied basins

Erratum to: Comparative assessment between GR model and tank model for rainfall-runoff analysis using Kalman filterapplication to Algerian basins-.

Modeling the rainfall-runoff relationship with conceptual models has always been a fascinating subject for hydrologists in view of its practical importance and complexity. This study presents a comparative assessment of the performance of two well established rainfall-runoff conceptual models. A first model called: Model ‘Genie Rural’ (i.e. Agricultural Engineering) and abbreviated GR, developed by Cemagref has been extensively tested in the Mediterranean watersheds and some basins in African countries. When applied to Algerian basins, the different version of the GR model gave satisfactory results, particularly for long time steps (monthly and annual data). In this work, the tank Model by Sugawara using Kalman filter for adaptive calibration is developed and tested for the first time to assess rainfall-runoff in Algerian basins. The results appear to be very prominent and far better than those given by the GR models including daily time steps. Indeed, a comparison between the two models established for daily and monthly data was performed on the three (03) Algerian Basins (i.e. Isser, Zardezas basin and Cheffia). Calibration of the Tank model parameters was performed by Kalman filter. Furthermore, the structure of tank model (i.e: number of tanks, number of outlets in each tank, and their location) was determinated for the studied basins