CURRENT STATUS AND WAYS TO IMPROVE THE EFFICIENCY OF THE DEVELOPMENT OF "KALMAZ" UNDERGROUND GAS STORAGE FACILITIES (UGSF)
Authors: Lala Abdullayeva, Mehriban İsmayilova Lala Abdullayeva, Mehriban İsmayilova , Tarverdi Mammadov Tarverdi Mammadov 
Published: June 2023

Geological structure of the "Kalmaz" oil and gas field, that is being studied since 1930, is located 100 km south-west of Baku, in the north-eastern part of the lower Kura depression.
Information on geological structure, stratigraphy, tectonics, oil and gas content of the field etc. has been collected as a result of the search and exploration works carried out and structural and research wells drilled.
The "Kalmaz" field was formed from the brachianticlinal fold with south-east direction from north-west. The structure is divided into separate blocks by tectonic faults, and the blocks are not interconnected.
Data on stratigraphic affiliation, lithology and thickness of stratigraphic units of sediments participating in the geological section of the site were obtained on the basis of deep wells drilled here. Upper Miocene-Pont, Pliocene and Quaternary sediments are involved in the geological section of the site.
Tectonically, Kalmaz brachianticlinal is located in the north-eastern part of the lower Kura depression, over the Kalameddin-Bandovan anticline zone, between Mishovdag in the West and Khidirli folding in the East. The Kalmaz structure is mainly stretched in the north-west – south-east direction, however in the western part the axis of elongation of the structure takes a close direction to the latitude circle. The structure is asymmetrical. North-east wing is upright (lying angle is 35-400) and short, the south-west wing is relatively low-leaved (22-300) and being extensive passes to the south-east Shirvan syncline.
The geological aspects of the structure was complicated by a fault that cuts its elongation at a certain angle. In the western part, tectonic fault passes through the north-east wing of the structure and through the south-west wing in the eastern part. As a result of the change in the direction of the axis of the fault structure, which is being talked about, cuts off the north-eastern wing in the western part, almost perpendicular to its lengthway and passes to the neighboring Navahi syncline. As a result of the fracture, the north-eastern wing of the Kalmaz structure and the south-western pericline were broken and dropped due to other parts of the fold. It's worth to note, that the Kalmaz structure has a very complex structure. This is also denoted by the Kalmaz mud volcano located in the central part of the fold.
Despite the study of the geological aspects of the site by various methods and the numerous wells drilled here, its deep tectonics and connection with neighboring Mishovdagh and Khidirli structures have not been sufficiently studied.
Numerous natural oil and gas manifestations are found in the site due to mud volcano springs. The mud volcano, located in the arch part of the fold, is related to a disruption that cuts its north-east wing. There is an active oil and gas flow from the mud springs arranged on a line in the direction of this disruption. Gas discharge related to Absheron sediments was detected in the structural mapping wells No. 39, 40, 41, 42, 44, 46 drilled on this strip. In most of these wells, the gas discharge passed into the gas fountain and lasted for a long time.
40000 m3/day gas and oil was obtained from the bottom Absheron sediments in the search well No. 87/2 located in the research site.
In the well No. 15, drilled in a tectonic block in the south-eastern part of the fold, oil with a daily output of 38-39 t was obtained from the IV horizon of the productive layer (PL). Gas with daily production of 22 200 thousand m3 was obtained from the upper horizon of the PL in the search and operation well No. 22, and of 180 thousand m3 was obtained from the IV horizon of the PL in the well No. 40.
As a result of research and exploration drilling, the I, II, III, IV, V, VI horizons of Kalmaz site have been proven to contain oil and gas.
These facts show that the Kalmaz site has great oil and gas prospects. It should be noted that the presence of rich oil and gas underground gas storage facilitiess in the not yet opened and insufficiently studied lower horizons of the productive layer is beyond doubt.
For this reason, information on geological study, stratigraphy, oil and gas characteristics, development, well fund of Kalmaz field, the first underground gas storage facilities in Azerbaijan, was analyzed in the article and due to the fact that a number of problems arose during the joint exploitation of wells, it was proposed to develop the well by dividing it into horizons.
Keywords: gas, underground gas storage facilities, horizon, well, gas injection.