Forecasting of the present-day fractured hydrocarbon migration ways at the oil-and-gas search-prospect stage

UDK: 553.98
DOI: 10.24887/0028-2448-2021-4-24-27
Key words: fault-fracture system, reservoir fluid, helium, hydrogen, present-day migration processes, search-prospect stage, well
Authors: Прогнозирование современных трещинных миграционных путей углеводородов на стадии проведения поисково-разведочных работ

The results of original scientific investigation for the study of present-day “fracture” ways of the hydrocarbon migration within the Russian sector of the North-Western part of the Caspian sea are considered. The space connections between in the rocks internal structure (the presence of pervious micro-fracturing), in the oil-saturating of rocks, in the presence and quantitative content of rare gases (helium, hydrogen) in the composition of the reservoir fluids selected from search-prospect wells is established at the point level. The criteria for forecasting of the fault-fracture systems of young age (pervious for fluids) and of degree of activity within their present-day fluid-migration processes were the presence or absence of helium and hydrogen (having deep origin and specific physicochemical features of paramount importance for the present study) in the composition of formation fluids (oil, released gas, free gas). The differently oriented fault-fracture systems of young age within the North-Western part of the Caspian Sea are differentiated in the direction and activity degree of present-day migration processes within their limits. So, within the vertical and inclined fault systems (especially in the Southern and Eastern parts of the Russian sector of the North-West Caspian), present-day fluid-migration processes are developing very quickly. The fluids from wells crossing these faults contain helium and hydrogen throughout the section. But, within the horizontal multi-tiered fault-fracture system, regionally developed in the Middle Jurassic-Lower Cretaceous section, present-day fluid-migration processes are developing not so quickly. The helium is present in formation fluids from these fractured intervals, but the hydrogen is absent. The possibility of the forecast of the present-day hydrocarbon migration “fracture” ways on the point (well) level even at the oil and gas search-prospect stage is given.

References

1. Kas'yanova N.A., New concept for the structure and formation of the North Caspian Rakushechno-Shirotnyi swell (In Russ.), Geologiya nefti i gaza = The journal Oil and Gas Geology, 2017, no. 1, pp. 24–31.

2. Kas'yanova N.A., The role of young fracturing in the formation and spatial distribution of hydrocarbon deposits in the North-Western Caspian Sea (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2018, no. 5, pp. 36–39.

3. Kas'yanova N.A., Sovremennaya prostranstvenno-vremennaya migratsiya tektonicheskoy napryazhennosti v zemnoy kore Kavkaza i Predkavkaz'ya (Modern spatio-temporal migration of tectonic tension in the earth's crust of the Caucasus and Ciscaucasia), In: Obshchaya i regional'naya geologiya, geologiya morey i okeanov, geologicheskoe kartirovanie (General and regional geology, geology of seas and oceans, geological mapping), Moscow: Geoinformmark Publ., 1994, no. 3, pp. 1–15.

4. Kas'yanova N.A., Abramova M.E., Gayrabekov I.G., Horizontal deformations of the Eastern Caucasus based on high-precision geodetic measurements (In Russ.), Geotektonika, 1995, no. 2, pp. 86–90.

The results of original scientific investigation for the study of present-day “fracture” ways of the hydrocarbon migration within the Russian sector of the North-Western part of the Caspian sea are considered. The space connections between in the rocks internal structure (the presence of pervious micro-fracturing), in the oil-saturating of rocks, in the presence and quantitative content of rare gases (helium, hydrogen) in the composition of the reservoir fluids selected from search-prospect wells is established at the point level. The criteria for forecasting of the fault-fracture systems of young age (pervious for fluids) and of degree of activity within their present-day fluid-migration processes were the presence or absence of helium and hydrogen (having deep origin and specific physicochemical features of paramount importance for the present study) in the composition of formation fluids (oil, released gas, free gas). The differently oriented fault-fracture systems of young age within the North-Western part of the Caspian Sea are differentiated in the direction and activity degree of present-day migration processes within their limits. So, within the vertical and inclined fault systems (especially in the Southern and Eastern parts of the Russian sector of the North-West Caspian), present-day fluid-migration processes are developing very quickly. The fluids from wells crossing these faults contain helium and hydrogen throughout the section. But, within the horizontal multi-tiered fault-fracture system, regionally developed in the Middle Jurassic-Lower Cretaceous section, present-day fluid-migration processes are developing not so quickly. The helium is present in formation fluids from these fractured intervals, but the hydrogen is absent. The possibility of the forecast of the present-day hydrocarbon migration “fracture” ways on the point (well) level even at the oil and gas search-prospect stage is given.

References

1. Kas'yanova N.A., New concept for the structure and formation of the North Caspian Rakushechno-Shirotnyi swell (In Russ.), Geologiya nefti i gaza = The journal Oil and Gas Geology, 2017, no. 1, pp. 24–31.

2. Kas'yanova N.A., The role of young fracturing in the formation and spatial distribution of hydrocarbon deposits in the North-Western Caspian Sea (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2018, no. 5, pp. 36–39.

3. Kas'yanova N.A., Sovremennaya prostranstvenno-vremennaya migratsiya tektonicheskoy napryazhennosti v zemnoy kore Kavkaza i Predkavkaz'ya (Modern spatio-temporal migration of tectonic tension in the earth's crust of the Caucasus and Ciscaucasia), In: Obshchaya i regional'naya geologiya, geologiya morey i okeanov, geologicheskoe kartirovanie (General and regional geology, geology of seas and oceans, geological mapping), Moscow: Geoinformmark Publ., 1994, no. 3, pp. 1–15.

4. Kas'yanova N.A., Abramova M.E., Gayrabekov I.G., Horizontal deformations of the Eastern Caucasus based on high-precision geodetic measurements (In Russ.), Geotektonika, 1995, no. 2, pp. 86–90.



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