The Impact of Thermogas Technologies on the Bazhenov Formation Studies Results

Abstract

Abstract At present time; there is change in the structure of Russian oil raw materials production by increasing the share of hard and unconventional hydrocarbons. The main reserves of unconventional hydrocarbon deposits in Russia are concentrated in Bazhenov Formation (BF). BF deposits occur at depths 2500–3000 m, the thickness is from 10 to 44 meters. Reservoir temperature varies from 80 º C to 134 º C. BF deposits are similar to the oil shale, but their distinguishing feature is that the process of converting organic matter into oil is not complete yet. So alongside with light oil, collector contains hydrocarbons directly in the form of the rock-forming constituent parts, called kerogen. Thus, the organic part of the BF is presented in two forms: liquid hydrocarbons – light oil with an average grade of 7.2% of the volume of rock and kerogen with an average grade of 23.3% of the rock volume. Kerogen is the main part of the organic material in the sediments of the Bazhenov Formation and is considered as a substance that generates on stage katagenesis major amount of oil and gas. BF Hydrocarbon resources are estimated in 50 to 150 billion tonnes according to many experts. At the present time BF hydrocarbon resources is used inefficiently. Experience shows that the use of traditional methods of development has led to the recovery of only 3–5% of oil contained in the pore space. OJSC "RITEK" is developing thermogas technology, taking into account the huge potential of the production of hydrocarbons from the BF. The most important condition for applying thermogas impact on the rocks of the BF is based on the field and laboratory results that the filtration and capacitive characteristics of rocks of the BF is largely determined by the level of temperature (Fig.1). For all types of kerogenic rocks noted an increase in porosity and permeability, the initial flow rate, cumulative production, hence the drainage area with the increase in temperature. Numerous experimental studies have shown that increasing the micropore (matrix) temperature to 250–350 not only allow to produce 70–80% of the initially contained therein light oil but to convert part of kerogen in hydrocarbons (Fig.2).