A study of mud volcano formation by basin modeling in the lower kura depression, South Caspian basin, Azerbaijan

Abstract

A mud volcano is a landform that forms as mud, water, and gases are released to the surface of the earth. Mud volcanoes can occur as a result of many geological processes. Since mud volcanoes do not generate lava because they are not fueled by magmatic activity. Mud volcanoes can be as little as one or two meters high and two meters broad or as large as 700 meters high and ten kilometers wide. Sometimes mud-pots are used to describe smaller mud exudations. Lower Kura Depression (LKD) and, South Caspian Basin (SCB) are unique places on Earth where enormous oil and oil-gas-condensate deposits coexist with oil-gas mud volcanoes. The presence of oil-gas and mud activity in nearly every one of this region's explored hydrocarbon sites attests to their intimate relationship. Mud volcanoes (MVs) have deep roots that reach oil and gas production zones, and as a result, they act as fluid passageways of hydrocarbons to higher structural levels. The South Caspian Basin hosts more than 30 % of the World's mud volcanoes. Significantly large mud volcanoes were developed in this area as a result of favorable tectonic processes, depositional settings, and subsurface pressure and temperature conditions. MVs can be many kilometers broad and several hundred meters high in certain areas. As a source of hydrocarbon gases, they feed the hydrosphere and atmosphere with enormous amount of gases that contribute to the the greenhouse effect and climate change. For instance in the LKD, mud volcanoes are associated with oil and gas fields. By means of their explosive eruptions and instability of the nearby gas-saturated sediments, they may also have adverse effects on drilling operations, rig installations, and pipeline routings. The purpose of this study is the investigation of the main causes of mud volcanos in the Lower Kura Depression of the South Caspian Basin in Azerbaijan. In the Lower Kura Depression there are 33 mud volcanoes that are active. The thickness of the sedimentary pile in the Lower Kura Depression reaches 25 km. This indicates that the sediment accumulation in the region is proceeding at a high rate. Avalanche sedimentation is characterized by a high rate of sedimentation exceeding 100 mm/1000 years and 1000 mm/1000 years, respectively. For this reason, high sedimentation rate is known here as one of the factors that cause overpressure and trigger mud volcanoes. For investigating these factors, PETROMOD 2D basin modeling program has been used.