INVESTIGATION OF PETROLEUM FORM NEW WELLS OF EASTERN GEORGIA

Investigation of new wells of Satskhenisi oil (#7, #11, #12, #13, #14) and Manavi oil (#11, #12) was carried out. By IR spectroscopy it was established that Satskhenisi oil belonged to naphtheno-aromatic type and Manavi oil – to paraffinic type of oils. According to distribution of trace elements V, Fe, Ni, Co, Mo, Cu, Pb, Sn, Zn, Sr, Ba, Ti and the ratio V/Ni <1, these oils refer to tertiary types of oils, which is explained by conditions of accumulation and geochemical transformation of the original organic compounds. Using simulation chromatographic distillation of Manavi oil from the #12 well were obtained naphtha and diesel fractions. In naphtha by method of gas-liquid chromatography were identified individual paraffinic, naphthenic and aromatic hydrocarbons and in diesel fraction – individual n-paraffinic hydrocarbons.By low content of sulfur, tar-asphaltene compounds and high yield of light fractions, Satskhensi and Manavi crude oils are high-quality raw material for production of commercial oil products for energy purposes. KEYWORDS


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specialists, the expected oil resources in Georgia make 2 billion 350 million tons, and of gas -180 billion m 3 . Even in case of development of 40-50% of this potential resource, the country's budget will receive a profit of several hundred billion dollars.
It was established that according to the physical and chemical parameters Georgian oils belong to unique, low-sulfur, high-quality oils and from the point of view of processing they are quite an interesting raw material. Studies of these oils have shown that in Georgia there are almost all known types of oils that differ from each other by their chemical nature (paraffinic, naphthenic, naphtheno-aromatic, aromatic, etc.). Through the study of oils and their physical, chemical and geochemical parameters using uniform integrated methods, it is possible to plan the production of commercial oil products for energy purposes of local industry and agriculture, which is of great importance for the determination of the country's energy resources and their rational management [1][2][3][4][5].
The goal of the work was investigation of new wells of petroleum from Satskhenisi and Manavi oilfields for their certification. Satskhenisi oilfield is located at the eastern part of Gare-Kakheti oil region in the north wing of Norio-Khashmi anticlinal at a distance of 30 km to the northeast from Tbilisi. Satskhenisi anticlinal is composed of Maikop and Miocene sedimentary structures [6] and Manavi oilfield is located to the south from the Kakheti Range at a distance of 60 km from Tbilisi, to the north-south of the dome of the Ninotsminda oil-bearing anticline with corresponding sedimentary structures consisting of oil-containing Upper Cretaceous paleogenic sediments.
In connection with the rehabilitation of Satskhenisi oil production and for the purpose of certification of Georgian oils five new wells (№№ 7, 11, 12, 13, 14) of Satskhenisi oil with depth of occurrence 1040-1400m have been studied [7,8]. Physical and chemical characteristics and the possibility of obtaining commercial oil products were investigated. Physical and chemical characteristics of the investigated oils are shown in Table 1. The results showed that all these crude oils are characterized by low density (765.0-816.0 kg/m 3 at 15°C), viscosity (0.92 -2.48 cSt), small amount of paraffins (0.04-1.1%), sulfur (0.1%), and tar and asphaltenes (0.24-2.27%) [9]. Distillation curves of crude oils of all five wells showed that they are characterized by high content of light fractions boiling below 320 °C with a yield of 80-92%.
Temperature-distillation chart shows that similarly to previously produced crude oils new wells of Satskhenisi oilfields are characterized by high content of light fractions. Temperature-distillation chart of oils from the new wells with initial boiling point below 320 C is shown in Figure 1.

Fig. 1. Temperature-distillation chart of oils from new wells of Satskhenisi Petroleum
At present, general accepted approach for carrying out comprehensive studies of composition of oils is a method of infrared spectrometry. The structural and group composition of crude oils and their components is determined by intensity of characteristic absorption bands in IR spectra using common baseline with fixed points at 1850 and 650 cm -1 . Content of methylene groups (CH2) in average molecule is assessed by absorption band at 720 cm -1 , content of methyl groups (CH3)by the absorption band at 1380 cm -1 , of sulfoxide groups (SO) by the absorption band at 1030 cm -1 and of carbonyl group (CO) in the region of 1720-1700 cm -1 with respect to C = C aromatic bonds by absorption band at 1600 cm -1 .
We have studied the results of infrared spectrometric analysis of crude oils from new wells, which was performed on a Perkin Elmer Spectrum spectrometer (model 10.4.2). The infrared spectra of all studied oils are presented in Figure 2.  Due to the high yield of light fractions of the Satskhenisi oil, the light commercial oil products naphtha, kerosene and diesel fuelswere isolated and investigated. The study of the above mentioned commodity oil products showed that they meet the requirements of the relevant standards.
Oil production in wells #11 and #12 is carried out by the company Canargo Energy Corporation. Reserves of wells make 130 million barrels of oil and 59 billion cubic pounds of 2C gas (NSA). Perforation interval is 4680-4953 m. Physical and chemical characteristics of the crude oil from the Manavi oilfield are shown in Table 2. The oil under study is characterized by medium density, high yield of light fractions (68%) and low content of sulfur and tar-asphaltenic compounds (8.92%), paraffin content is 6.1%. Simulation of complete distillation of crude oil was performed on a Sim Dis chromatograph, Auto System XL, manufactured by Perkin Elmer, according to ASTM D 2887 standard [10]. The crude oil under study is characterized by a high content of light fraction; the residue above 500°C is 12.5%. The distillation curve for Manavi oil is shown in figure 3.

Fig. 3. Distillation curves for Manavi oil, wells #11 and #12
An infrared spectrometric analysis of oils from new wells, carried out on a Perkin Elmer Spectrum spectrometer, model 10.4.2., showed that the IR spectra of the wells are almost identical. The intensity of the absorption bands of 721.4 cm-1 and 1377 cm-1 characterizes the content of methyl and methylene groups in paraffin hydrocarbons. The presence on the spectrum of the band 1600cm-1 characterizes the content of aromatic hydrocarbon. It has been determined that crude oils of the new wells of the Manavi oilfield have the same chemical composition and refer to the paraffin type of Petroleum.

Fig. 4. IR spectra of Manavi Crude Oil
From the results of the study, it turned out that due to the low content of sulfur, tar-asphaltenic compounds and high yield of light fractions, the Manavi oil was high-quality paraffinic oil.
The naphtha fraction isolated from the Manavi crude oil (35-180°C) was studied by the gas chromatography method "PON A" [11]. The elemental and group hydrocarbon composition, molecular weight, relative density, saturated vapor pressure and octane number were determined (Table 3). Individual paraffinic, naphthenic and aromatic hydrocarbons and their derivatives were also identified.  In the carbamide concentrate of the diesel fraction 180-320ºС, the distribution of n-paraffin hydrocarbons was studied by a gas-liquid chromatography (Table 5). In this table are shown the identified n-paraffin hydrocarbons C9-C26, with a maximum content of tetradecane (C14H30). The distribution of trace elements V, Fe, Ni, Co, Mo, Cu, Pb, Sn, Zn, Sr, Ba, Ti in Satskhenisi and Manavi oils was also studied. Trace elements were isolated using the developed in the laboratory of petroleum chemistry photochemical method of extracting the concentrate of ash elements from petroleum and petroleum products, which has found wide application in other scientific research organizations. Consequently, on the basis of the study it was concluded that distribution of V, Fe, Ni, Co, Mo, Cu, Pb, Sn, Zn, Sr, Ba, Ti microelements and the ratio V/Ni <1 indicate that these oils are of tertiary type, which can be explained by conditions of accumulation of initial organic substance and by relevant geochemical origin [12].
The results of the study. The oils of the new wells of the Satskhenisi and Manavi oilfields, located quite close to each other in the region of the Kakheti Range were studied. Physical, chemical and geochemical parameters, as well as functional groups by IR spectrometry, were determined. It has been established that Satskhensi oil refers to naphthene-aromatic, and Manavi oil to paraffin types of oils.