RU2499285C1 - Method of hydrocarbon pool proceeding from principle of passive adsorption - Google Patents

Abstract

FIELD: oil-and-gas industry.

SUBSTANCE: hydrocarbon gases are sorbed by means of nonexpendable sorbents-collectors in soil bores deep to at least 0.5 m. Note here that said sorbents-collectors at elevation of expected productive beds are located in dense grid with spacing of 250-400 m there between while, outside said elevations in loose grid, of 500-800 m. Samples are analysed to accuracy of 1 picogram to extract at least 150 hydrocarbons. Results of the analysis are compared with reference data. Said data is interpolated in algorithm of training and mapping system with the help of analysis of primary components, discriminate analysis and hierarchical cluster analysis. Adapted criteria are used to simulate deposit.

EFFECT: higher accuracy.

5 dwg

Description

The invention relates to petroleum geology, in particular to the search and exploration of oil and gas (bitumen) deposits.

There is a method of searching for oil deposits, including the extraction and natural concentration of hydrocarbons on the sorbent from the pore air of soils, the determination of the spectrum of hydrocarbons and their concentrations using gas chromatography, which are used to determine the presence of an oil deposit. A method of forced adsorption of pore soil air is used; soil air is taken from a depth of 1.4-1.5 m using a vacuum pump. The evacuated air is passed through a filter. The air purified by the filter from aerosols and dust is passed through a combined sorbent, on which hydrocarbon compounds are analyzed, which are analyzed (RF patent No. 2272307, IPC G01V 11/00, published on March 20, 2006).

The disadvantage of this method is the time-consuming process of selection and purification of soil air.

Known geochemical method for the search for hydrocarbons, which consists in sampling and extraction from them of chemical elements in mobile forms. At each observation point, soil samples are taken from the upper humus horizon A1 and horizon C. enriched with ferromanganese compounds. The hydrocarbon indicator elements associated with organic soil compounds and associated with ferromanganese compounds are extracted. Under the action of a constant electric current, the hydrocarbon indicator elements are extracted in electrically mobile forms. Anomalous concentrations of selected indicator elements are distinguished, coincidence areas are combined, as a result of which the boundaries of oil and gas provinces or individual deposits are determined (RF patent No. 2097796, IPC C01V 9/00, published on November 27, 1997).

The main disadvantage of this method is the complex scheme associated with the analytical determination of indicator elements, the latter being in micro quantities in the samples, are secondary neoplasms introduced due to migration from a hydrocarbon deposit. Their characteristics are more likely to be of a general evaluative nature and do not fully reflect the true state of oil and gas resources.

Closest to the proposed is a method for the diagnosis of hydrocarbon deposits (R. S. Khisamov et al. The use of the GORe-Sorber method in a complex of geophysical and geochemical studies in the diagnosis of hydrocarbon deposits / Georesursa, No. 1, 2009, pp. 29-32 - prototype). The method includes placing sorbers-collectors in the soil openings, carrying out technological exposure for sorption by hydrocarbon gas collectors, extracting sorbers-collectors from the holes, analyzing samples by the thermal desorption – gas chromatography chain — massively detecting hydrocarbon compounds, determining hydrocarbon gases in samples by passive adsorption to an accuracy 1 picogram (1 × 10 ^-12 grams), comparison of analysis results with reference data, data interpretation in the learning system algorithm and mapping using the analysis of the main components, discriminant analysis and hierarchical cluster analysis, according to the trained criteria, modeling reservoirs,

The known method is not accurate enough in assessing the likelihood of a hydrocarbon deposit.

The proposed invention solves the problem of increasing the accuracy of the search for hydrocarbon deposits.

The problem is solved in that in the method of searching for hydrocarbon deposits based on the principle of passive adsorption, including placing sorbers-collectors in the soil openings, holding technological extracts for sorption by sorbers-collectors of hydrocarbon gases, extracting sorbers-collectors, analyzing samples, determining hydrocarbon gases in samples passive adsorption with an accuracy of 1 picogram, comparison of analysis results with reference data, interpretation of data in the algorithm of the training system and mapping with using the analysis of the main components, discriminant analysis and hierarchical cluster analysis, according to the trained criteria, reservoir simulation according to the invention, reusable collectors are used as sorbers-collectors, at least 150 hydrocarbon compounds are isolated during analysis, when sorbers-collectors are placed in soil holes holes in the soil are formed with a metal rod to a depth of about 0.5 m, the placement of sorbers-collectors is carried out on the area of the proposed field, while above m The sorbers-collectors are arranged on a dense grid with a distance between the sorbers-collectors of 250-400 m by the uplifts of the proposed productive formations of the field; outside the lifts, the sorbers-collectors are located at a distance of up to 30% of the length of the rise along a rare grid with a distance between the sorbers-collectors of 500-800 m

SUMMARY OF THE INVENTION

Existing methods for the search for hydrocarbon deposits require drilling, and the analysis of hydrocarbon compounds is limited to several compounds, which increases the timing of field work and reduces the accuracy of the analysis. The proposed invention solves the problem of reducing the timing of field work, expanding the number of identified hydrocarbon compounds, improving the accuracy of the search for hydrocarbon deposits. The problem is solved as follows.

The proposed method is based on the sedimentary migration concept of the origin of oil and the study of the migration of chemical elements in the earth's crust.

The vertical diffusion-filtration mass transfer of hydrocarbons from oil, gas and bitumen deposits leads to the formation of anomalies or fields of abnormal concentrations of hydrocarbons and associated components in the overlying deposits. Tectonic, lithological, geothermal and hydrogeological factors determine one or another mechanism of mass transfer - fluid migration through the strata of the rocks overlapping the reservoir in the form of macroseparation, along faults in geological structures, or vertical microseparation, through the thickness of the sedimentary deposits that overlap the reservoir. The problem of determining the vertical diffusion-filtration mass transfer of hydrocarbons is solved by applying the principle of passive adsorption of hydrocarbons in soil-ground air using a sorbing collector. The mechanism of adsorption of soil gas is based on a membrane-controlled selection of hydrocarbon compounds by a sorbing collector. In the sorbing collector, the adsorption of hydrocarbon compounds is carried out on an adsorption cartridge, which is a cylinder made of stainless steel mesh with cells of 3 × 8 mm and a diameter of 4.8 mm, filled with 350 mg of graphitized charcoal with a particle size of 35-50 mesh. The used sorber-collector is reusable, which helps to identify measurements and, ultimately, increase the accuracy of measurements.

A sorbent collector with a membrane-controlling material prevents direct physical contact of the adsorbing material with particles of soil, soil and moisture, guaranteeing a mechanism for collecting hydrocarbon compounds in gaseous form, which gradually accumulate on the absorbent material in a certain period of time.

The technology of the proposed method is as follows. According to geophysical research, uplifts are determined in the area of the proposed oil field. Placement of sorbers-collectors is carried out on the area of the proposed field, while in places of elevations of the proposed productive formations, sorbers-collectors are arranged on a dense grid with a distance between sorbers-collectors of 250-400 m, outside the elevations, sorbers-collectors are located up to 30% of the length of the rise on a rare grid with a distance between sorbers-collectors of 500-800 m.

The soil of the test object is manually punctured with a borehole (metal rod), forming a hole with a depth of 50 cm and a diameter of up to 1.5 cm. A sorbent collector is placed in the hole using a metal guide pin. The sample location is marked on the map, and the coordinates are fixed using the receiver of the global positioning system (GPS), which is equipped with a buffer for storing data and subsequent uploading to a personal computer. The exposure time of the sorbing collector in the soil is from 17 to 21 days. This period of time has been evaluated empirically and has established itself as optimal for most areas and climatic conditions. However, this period increases for specific local conditions, such as heavy precipitation, extreme cold. After a certain number of days, the sorbent-collector is removed from the soil by means of a cord fixed in its upper part and placed in a sealed glass vessel with a tight-fitting lid and sent to the laboratory.

In the laboratory, chemical analysis is carried out along the thermal desorption - gas chromatography - mass-selective determination of hydrocarbon compounds using analytical equipment, for example, Shimadtsu (Japan) or Agilent (Canada). This analysis scheme allows you to determine the hydrocarbon content in geochemical samples with passive adsorption to within 1 picogram (1 × 10 ^-12 grams), to identify more than 150 compounds, including normal alkanes, isoalkanes, cycloalkanes, aromatic hydrocarbons, polycyclic aromatic hydrocarbons, alkenes, aldehydes etc. from C ₂ (ethane) to C ₂₀ (phytan). The content of hydrocarbon compounds is determined in absolute units - nanograms using tenths and hundredths of the latter, which allows this technology to be referred to as the so-called "nanotechnology". The statistical processing of data from geochemical samples is based on a comparison of the data of each sample of the test object with the data of the samples around known reference objects - empty, equivalent to 0%, and productive, equivalent to 100% (Fig. 1).

Based on the comparison of these samples with the reference, each geochemical sample receives its percentage of probability from 0% to 100% with respect to the reference samples. Based on the obtained probabilities of geochemical samples, they compose a geochemical map of oil (gas-bitumen-) similar probabilities of detecting hydrocarbon deposits. Subsequently, geochemical modeling is performed.

The forecast data are confirmed by the probabilities of oil content (bitumen, gas content) in the range of 90-100%. The contour of the alleged surface deposits is an isoline at 75% probability.

Expanded geochemical modeling consists in interpreting the data using multivariate statistical analysis methods, excluding compounds that do not meet specified conditions for the signal-to-noise ratio, and analyzing using statistical methods, including principal component analysis (ASC), discriminant analysis (YES), and hierarchical cluster analysis (IKA). With their help, a summary chemical “image” of the analyzed compounds and modeling criteria for interpreting the results are determined. At the final stage, the obtained probability values are mapped using mapping methods.

As a result, it is possible not only to determine the presence of an oil field, but also to separate individual oil deposits located at different depths or deposits separated by a non-reservoir in the field.

Concrete example

Search for hydrocarbon deposits at the Popovkinsky seismic uplift in the Ulyanovsk region. Analyze the data of geophysical studies of the area, identify the places of elevations of probabilistic productive formations. On the surface of the earth above the elevations of the proposed productive formations, the sorbers-collectors are arranged on a dense grid with a distance between the sorbers-collectors of 250-400 m, outside the lifts, the sorbers-collectors are located at a distance of up to 30% of the length of the rise along the rare grid with the distance between the sorbers-collectors 500-800 m.

The soil is manually punctured with a borehole (metal rod), forming a hole with a depth of 50 cm and a diameter of up to 1.5 cm. A reusable sorbing collector is placed in the hole using a metal pin. A reusable sorbing collector with a code of 123-2 is used as a collection sorber.

The sample location is marked on the map, and the coordinates are fixed using the receiver of the global positioning system (GPS), which is equipped with a buffer for storing data and subsequent uploading to a personal computer. The exposure time of the sorbing collector in the soil is from 17 to 21 days. Each sorbing collector is removed from the soil by means of a cord fixed in its upper part, and placed in a sealed glass vessel with a tight-fitting lid and sent to the laboratory.

In the laboratory, chemical analysis is carried out along the thermal desorption - gas chromatography - mass-selective determination of hydrocarbon compounds using analytical equipment from Shimadtsu (Japan) with a GCMS-QP2010 Plus chromatography mass spectrometer and Agilent 7890 (Canada). Analytical studies, as suggested by the experience of chemical-analytical and characteristics of the equipment used, can be carried out on other devices with minor tweaks, the main feature is the high sensitivity of the devices and a wide range of detectable compounds. The hydrocarbon content in geochemical samples with passive adsorption is determined with an accuracy of 1 picogram (1 × 10 ^-12 grams) and more than 150 compounds are detected. The content of hydrocarbon compounds is determined in absolute units - nanograms using tenths and hundredths of the latter. The results of the most characteristic analysis are presented in the table.

The list of analyzed compounds by classes of compounds Typical oil components In parentheses () is the carbon number Common alkanes Isoalkanes Cyclic alkanes Aromatic compounds and PAHs * Ethan (2) 2-Methylbutane (5) Cyclopentane (5) Benzene (6) Propane (3) 2-Methylpentane (6) Methylcyclopentane (6) Toluene (7) Bhutan (4) 3-Methylpentane (6) Cyclohexane (6) Ethylbenzene (8) Pentane (5) 2,4-Dimethylpentane (7) cis-1,3-dimethylcyclopentane (7) m, p-Xylene (8) Hexane (6) o-Xylene (8) Heptane (7) 2-Methylhexane (7) trans-1,3-dimethylcyclopentane (7) Propylbenzene (9) Octane (8) 3-Methylhexane (7) 1-Ethyl-2/3-methylbenzene (9) Nonan (9) 2,5-Dimethylhexane (8) trans-1,2-dimethylcyclopentane (7) Dean (10) 1,3,5-Trimethylbenzene (9) Undecan (11) 3-Methylheptane (8) Methylcyclohexane (7) Dodecanese (12) 2,6-Dimethylheptane (9) Cycloheptane (7) 1-Ethyl-4-methylbenzene (9) Tridecan (13) CIS-1,3 / 1,4-Dimethylcyclohexane (8) Tetradecane (14) Pristan (19) 1,2,4-Trimethylbenzene (9) Fitan (20) cis-1,2-dimethylcyclohexane (8) Pentadecane (15) Indan (9) trans-1,3 / 1,4-dimethylcyclohexane (8) Inden (9) Hexadecane (16) Butylbenzene (10) trans-1,2-dimethylcyclohexane (8) 1,2,4,5-Tetramethylbenzene (10) Heptadecane (17) Ethylcyclohexane (8) Naphthalene (10) Octadecan (18) Cyclooctane (8) 2-Methylnaphthalene (11) Propylcyclohexane (9) Acenaphthylene (12) By-products / modified and other compounds Alkenes Aldehydes Biogenic ASA * and other compounds Ethene (2) Octanal (8) Alpha pinen Furan Propene (3) Nonanal (9) Beta pinen 2-methylfuran 1-Butene (4) Decanal (10) Camphor Carbon disulphide 1-Penten (5) Karyofillen Benzofuran 1-Hexene (6) Benzothiazole 1-Hepten (7) Carbonyl sulfide 1-Octen (8) Dimethyl sulfide 1-Nonen (9) Dimethyl disulfide 1-Decen (10) 1-Undecen (11) PAH - Polycyclic aromatic hydrocarbons; ASA - compounds containing nitrogen, sulfur and oxygen.

To bring the reusable collector-sorter into working condition for new studies, it is heat treated in a stream of nitrogen at a temperature of about 350 ° C for 8 hours.

Mathematical processing of data of geochemical samples is carried out, which is based on comparing the data of each sample of the studied object with the data of samples around known reference objects - empty, equivalent to 0%, and productive, equivalent to 100%.

) отмечен контур залежи нефти. Значения вероятности выше 75% указывают на области, по геохимическим показателям схожие со сводным образом нефтяной залежи, установленной от эталонной скважины.Based on the obtained probabilities of geochemical samples, they compose a geochemical map of oil (gas-bitumen) similar probabilities of detecting hydrocarbon deposits. The map determines the surface contour calculated using a computer based on the probability value determined for each sampling point. The configuration of the contoured surface depends on the distance between the samplers, the density of their installation, and also on the probability values of the samples. The contour of the alleged surface deposits is an isoline at 75% probability. Figure 2 bold line (

) the contour of the oil pool is marked. Probability values above 75% indicate areas that are similar in geochemical parameters to the consolidated image of an oil reservoir installed from a reference well.

Cluster analysis established groups of samples similar to the reference wells 64 (empty) and 70 (oil) and different from them. Figure 3 illustrates the allocation of a new class of oil that is different in geochemical parameters from the training standard of oil, this suggests that geochemical objects that differ in quantitative and qualitative characteristics of the component composition of hydrocarbon compounds have been identified in the study area.

).A comprehensive interpretation of the obtained geochemical results should be carried out in conjunction with the seismic and geochemical data of the studied area. In Fig. 4, the Popovkin structure is highlighted by a solid line (

)

). Геохимическая аномалия, как показано на фиг.4, локализуется в пределах Поповкинской структуры и простирается далее на восток и северо-восток от скважины 1, а также на восток и юго-восток от скважины 2 за пределы участка обследования. Направление распространения геохимической аномалии на фиг.4 отмечено стрелкой (

).As a result of the work, as shown in Fig. 4, a geochemical object was identified in the eastern part of the study site. The anomaly is stable, it is determined by 32 sequentially located sampling points, in which the component composition of hydrocarbon compounds as a result of analytical and statistical analysis methods is defined as identical to the image of well oil 70 with a probability value (75-100%). In Fig. 4, the geochemical anomaly of the image of the oil from the well 70 is indicated by a dashed line (

) The geochemical anomaly, as shown in Fig. 4, is localized within the Popovkin structure and extends further east and northeast of well 1, as well as east and southeast of well 2 beyond the survey site. The direction of propagation of the geochemical anomaly in Fig. 4 is marked by an arrow (

)

). Аномальные области с контуром изолиний 75-100% вероятности перспектив нефтеносности также выделены в западной части участка исследований, которые характеризуют дополнительные, вполне возможно самостоятельные, нефтеперспективные геохимические объекты, но в связи с их малым размером они не представляют практического интереса.In the southern part of the Popovkinsky uplift, a less stable geochemical object was identified by 6 anomalous sampling points (points No. 424110, 423939, 422891, 424042, 423936 and 422846), in Fig. 4, the geochemical anomaly is highlighted by a dot-dash line (

) Anomalous areas with contour contours of 75-100% probability of oil prospects are also highlighted in the western part of the research area, which characterize additional, quite possibly independent, oil-prospective geochemical objects, but due to their small size they are not of practical interest.

The results of geochemical studies at the Popovkinsky uplift made it possible to establish two promising contours of the probability of oil content, which served as a reason to recommend exploration wells 1 and 2 for drilling.

Drilling a well 1, as shown in Fig. 5, uncovered a hydrocarbon deposit of the Bashkirian stage of the Middle Carboniferous in the range of absolute elevations of 900-880 m. Drilled well 2, as shown in Fig. 5, discovered the oil productive deposits of the Kashirsky, Vereiskian horizons of the Bashkirian stage of the Middle Carboniferous in the intervals - 780-760 m and - 900-880 m. The geological section of wells 1 and 2 is shown in Fig. 5, where the oil-perspective intervals and horizons are highlighted. Thus, the drilled wells confirmed the multilayer reservoir.

Thus, it is shown that the proposed method has increased accuracy in determining oil deposits. The method is able not only to establish the presence of an oil field, but also to separate individual oil deposits in one field and even draw contours of the deposit.

The application of the proposed method will improve the accuracy of detection of oil deposits.

Claims (1)

A method of searching for hydrocarbon deposits based on the principle of passive adsorption, including placing sorbers-collectors in the soil openings, carrying out technological exposure for sorption by sorbers-collectors of hydrocarbon gases, extracting sorbers-collectors, analyzing samples, determining hydrocarbon gases in samples by passive adsorption to within 1 picogram, comparison of analysis results with reference data, interpretation of data in the algorithm of the training system and mapping using analysis of the main components entents, discriminant analysis and hierarchical cluster analysis, according to the trained criteria, reservoir simulation, characterized in that reusable collectors are used as sorbers-collectors, at least 150 hydrocarbon compounds are distinguished in the analysis, when holes are placed in the soil sorbers-collectors the soil is formed with a metal rod to a depth of about 0.5 m, the placement of sorbers-collectors is carried out on the area of the proposed field, while in the places of elevations of the alleged productive strata, sorbers-collectors are placed on a dense grid with a distance between sorbers-collectors of 250-400 m, outside the elevations, sorbers-collectors are located at a distance of up to 30% of the length of the rise along a rare grid with a distance between sorbers-collectors of 500-800 m.

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