EAGE/SPE Workshop on Shale Science 2017

New data on the origin, geological conditions, thermal maturity, generation potential of organic matter from Bazhenov Formation have been obtained. Investigation of content pyrolyzed hydrocarbon components, determination of maturity level and kinetics of thermal kerogen destruction, studying the microstructure and other properties of organic matter of a few sections from Bazhenov Formation from wells of the Frolovskaya Depression were carried out. Application of obtained data for the identification of potential reservoir intervals, calculation of hydrocarbon reserves and resources, petroleum basin modeling and the development of thermal EOR technologies is discussed

The paper presents the results of integrated experimental analysis of residual pore water content in a set of isolated core samples of the Bazhenov Formation taken from a well at one of the oil and gas fields in West Siberia, Russia. Additionally it includes measured values of cation exchange capacity and pore water composition of Bazhenov rocks obtained via composition analysis of water extracts. It was found that the free (presumably capillary) water content is 0.32÷2.53 wt%, the residual pore water content is 0.79÷3.70 wt%. The total amount of Na+, K+ and Cl- in the pore water of the Bazhenov Formation is determined to be 10.65÷79.21 g/L. The measured values of cation-exchange capacity (10.5÷14.72 meq/100 g of rock) correlate well with clay minerals content. Obtained results of the laboratory study was integrated with data of standard well logging suite. Free and residual water content was found to have low degree of correlation to each of logging channels in the suite. This circumstance indicates that it is impossible to get reliable estimate of Bazhenov Formation water saturation from standard well logging dataset, but also that obtained laboratory result is an independent variable of petrophysical model of Bazhenov reservoir rocks.

Mosaic netprotocol of the Bazhenov formation is determined not only by the uneven heating of vysokovitaminnym strata, but variability of the tectonic situation: the situation of the productive strata concerning the various faults and their fracture Operahuset. As a result, on-site Polanowska LOU appeared heterogeneous oil saturation (promising development) zone. The results of the research allow to make the next step in the solution methodology mapping of prospects with the development of the natural manifold, namely to conduct a mineralogical mapping vysokovitaminnym deposits in the area where they are first deposited directly on the early Mesozoic rhyolites (granites Paleozoiskiy young - intrusions) and in places where the lower Jurassic tyre. And second, isolated overlying and underlying sedimentary strata.

Reviewed material shows that multi-scale dolomitization, along with calcitization developed as in rich in organic matter (OM) in rocks and primary sedimentary limestones and calcareous rocks of the Bazhenov-Abalak complex. The flow rates of the wells penetrated these strata, in some cases, may vary greatly as the nature of the relationship between the imposed by dolomitization and sedimentary calcasola complex.

Vysokovitaminnym formation in the Bazhenov formation deposits syngenetic free (scattered) of oil and natural secondary manifold presented bituminoznye organogenic-clay rocks, containing disseminated dolomite in situ are paragenetic processes. The border appearance of scattered secondary dolomite in situ in the bituminous sediments should be considered the contour of the productivity of the Bazhenov formation with the presence of free oil

Currently, this is actual the study of shale oil in terms of creating artificial permeability (i.e. “rock fabric”). Usually the study of oil-bearing objects is limited to valuation the standard geological parameters, which are called ‘volumetric’ (net pay, porosity, permeability, oil and gas saturation, area, etc.), but they are not enough to describe the possibilities of shale oil development with using well stimulation techniques. For this purpose, it proposed to supplement the standard research methods to identify movable hydrocarbons, valuation of geomechanical parameters, lateral and vertical reservoir variability for purposes of drilling long horizontal wellbores. This article focuses on methods that can be used for these case

The increased interest in the development of low-permeability and low-porosity reservoirs leads to the necessity of developing new approaches to quantitative interpretation of geophysical data, providing the acquisition of more detailed information about the structure and properties of sediments by contrast to the traditional approach. The paper proposes techniques for determining the electrical parameters of a consistent geoelectric model explaining the behavior of lateral logging sounding and high-frequency electromagnetic sounding signals measured in vertical wells at intervals of the Bazhenov formation.

The technique is based on the present-day finite element numerical simulation and inversion of electrical and electromagnetic logging signals in a two-dimensional axisymmetric model, taking into account the resistivity anisotropy, dielectric permittivity and its frequency dispersion in the 0.875–14 MHz range. The resulting models fit the measured signals of the both methods within the measurement error, and focused lateral logs, which are not involved directly.

According to the data inversion results at intervals of the Bazhenov formation from more than twenty wells from Fedorovskoe, East-Surgutskoe and Russkinskoye fields, we determined the features of the resistivity anisotropy coefficient distribution and carried out the first numerical experiments to evaluate the values of the effective dielectric permittivity.

Bazhenov formation in point of seismic is clear amplitude marker horizon which is characterized by low values of acoustic velocity and density. The object of seismic forecast for this formation is complicated by the lack of productivity potential intervals clear defined characteristics in well logs, high compositionally-textural heterogeneity and presence of natural fractures. One of the methods to increase forecast reliability is modern technology of quantitative seismic interpretation based on the elastic rock model. Since bazhenov formation productivity potential intervals are mainly associated with dolomitization, which is appeared as a result of epigenetic alternation, it is important to take into account these processes considering areal forecast. To evaluate and analyze the factors influencing the bazhenov formation epigenetic alternation, it is beneficial to use the gravitational and magnetic survey interpretation results which provides data on the pre-Jurassic basement composition responsible for bazhenov deposits alterntion controlling. In this regard bazhenov formation productivity forecast requires to engage all the available geophysical data and multiple seismic processing and interpretation techniques attended by integration and mutual verification of the results. This paper considers the approach to predict sweet-spots of unconventional bazhenov formation on the basis of well data and areal geophysacal exploration methods.

Chemostratigraphy is a direction of science at the intersection of chemistry and stratigraphy dealing with the study of the chemical composition of sedimentary rocks. Lithochemical methods and algorithms of processing chemical datas for a long time and are successfully implemented in local geology as applied to black shale formations for a long time.

The problems of separation and correlation of fine multimineral black slates are one of the problems in the complex development of objects. Chemostratigraphic techniques, applied for the first time in the study of the bazhenov formation, worked well with the lithostratigraphic division of the section of BF in different structural-facies zones of the West Siberian OGP.

Petrochemical modules allow to divide quickly a section of the well material composition to chemotypes and further they can be used as an analog of material and structural types for creation of petrophysical models.

For a partition and correlation of sections of BG it is reasonable to use REE

Typification of a section on the chemical composition directly correlates with physical parameters, and allows for a quantitative basis to differentiate the material composition of rocks on lithochemical-based petrochemical modules.

Summary of all core and exploration research results of the Bazhenov formation are given.Different geological structure of the Bazhenov formation and its oil production and exploration in five regions of West Siberia are given. Relationship between reserviores, exploration conditions and degree of OM catagenesis are mentiond.

During the last recent years VI. Shpilman research and analytical Centre for the rational use of the subsoil carries out detailed studying of the Upper Jurassic Bazhenov Shale that is considered to contain the largest amounts of shale oil resource in the world. The sizable database of geologic information from the whole territory of Khanty-Mansiysk Autonomous Okrug-Ugra, which contains geochemical and lithologic analyses of core samples (from more than 300 wells), data of well tests, logs, seismic information and etc., allows to map various characteristics and construct a model of the Bazhenov shale.

The proved oil presence in the Bazhenov shale (spreading of discovered deposits, oil production rates) is compared with various lithological, mineralogical, geochemical and thermobaric factors. The critical parameters and their values were substantiated: reservoir temperature of the Bazhenov shale, specific hydrocarbon generation and maturation level of kerogen. The map of regional prospects of the Bazhenov shale was predicted by superposition the distributions of abovenamed parameters with taking into account spreading of the “Abnormal Bazhen” zones and hydrocarbon generation area boundaries. Five categories of lands of various degree of prospects are marked out.

The paper concerns the problem of quantitative hydrocarbons evaluation of Bazhenov formation itself. Geological features of formation are defined based on integrated multy-scale study. Differentiation of estimation target in reliance on dominated petroleum occurrence forms is crucial for the concerning formation. Different approaches should be implemented for similar to traditional reservoirs intervals, for rocks containing petroleum in isolated porosity, and for source rocks. Quantitive reserves and resources estimations of kerogen-containing rocks based on pyrolytic parameters should be controlled by volumetric method of evaluation. Objective reserves values could be obtained using pyrolysis before and after extraction and consider dependence between parameters and sample volume.

Accumulation of oil (field) in the domanic sediments is an area of layers distribution or groups of layers into the Domanic section in which oil is found in disseminated state and its petrophysical rock properties give opportunities to take commercial oil flows after carrying out reservoir fracturing. In Russia for commercial development and also pilot projects it is necessary to carry out the estimation reserve at once after deposit discovery. That is why for operative oil reserve estimation for unconventional it is possible use only reserves estimation volumetric method. For oil reserve estimation by volumetric method in Domanic is proposed the algorithm

“Oil slates” or bituminous carbonaceous rocks can be a source as existing, and potential oil. This circumstance shall be considered not only in case of assessment of resource potential, but also in case of development of technology of oil extraction from them. Including deposits of BS source rock, it is necessary to accept that all area of distribution of sediments of the Bazhenov measure and BS cross-section are productive or potentially productive.

Authors on the basis of results of modern researches of a core and techniques of complex interpretation of data of a core and GIS, the analysis of production on a number of fields of the Salym district proved model of cavitated space of rocks of BS developed nonconventional methodical approaches to handling of materials GIS, complexation of geochemical and geophysical parameters, established certain interrelations between petrophysical, mineralogical, geochemical parameters, created algorithms and techniques of determination of subcalculating parameters.

About three categories – amounts of free or mobile V1 oil, amounts of physically connected hydrocarbons or the released V2 oil, amounts of potential oil which can be received in case of kerogen destruction, or the petrogenerative potential of V3 of rocks of BS are recommended to carry out assessment of inventories of hydrocarbonic fluids.

Currently, Bazhenov Formation that contains large amounts of organic matter attracts high interest of oil companies. However, often the organic substance is at an early stage of katagenesis, drilled wells are dry. In this paper we show the results of laboratory experiments on the implementation of kerogen generation capacity and synthesis of oil. It is found that in a closed system in the presence of water at elevated temperatures and formation pressure oil could be produced, the composition of which will vary depending on the stage of katagenesis, temperature and duration of the experiment. This generation potential can be realized almost completely with about 35% of oil in products. Development of the technology for the hydrocracking in the formation can significantly increase the production of all wells, implementing oil factory in situ and producing the necessary products.

The report deals with preliminary test results of procedures for developing non-conventional oil reserves of Bazhenov formation at the Sredne-Nazymskoe oilfield (Joint Stock Company “RITEK”). It also lists the ways of improving the selected concepts for developing hard-to-recover reserves (HTR reserves)

Bazhenov Formation (BF) is the largest oil source rock in Western Siberia with one million square kilometers area. A significant part of BF is low-permeability reservoirs composed of highly organic-rich carbonate and siliceous rocks. Oil deposits of the BF have high vertical and lateral heterogeneity with lack of hydrodynamic connection among productive reservoirs, thus vertical and deviated wells have low oil recovery factor.

The most effective up-to-date technology of oil recovery for the BF is the multi-stage hydraulic fracturing (MHF) in horizontal wells. In ultra-low permeability reservoir with (MHF) of horizontal wells, the only way to maximize drainage area is to create induced fracturing – so-called stimulated reservoir volume (SRV).

In this paper presented results of developed specialized software for modeling (MHF) for low-permeability reservoirs (in particular, the BF) in order to determine the optimum technological parameters for generating an effective fracture network in the formation. Complex analysis of multi-stage hydraulic fracturing effectivity is possible by coupled solving of geomechanical problem of initiation, development and closing of hydraulic fractures and reservoir simulation of the inflow within the configuration of created stimulated reservoir volume.

Shale formations are one of the unconventional reservoirs, development and operation of which requires special technologies. Waterflooding can be used for improving recovery factor in the shale reservoirs under specific conditions. Inorganic salt precipitation can occur during water injection into shale reservoir depending on the pressure and temperature. Scale formation reduces rock permeability, and damages the production equipment. In this work, prediction of barium sulfate scale deposits was investigated at different reservoir pressures (0.1 to 70 MPa) and temperatures (40°C to 150°C). The scaling tendency of barium sulfate was increased by increasing pressure and decreasing temperature. However, temperature did not affect the amount of salt precipitation. In addition, scale inhibition was studied using five different scale inhibitors under static and dynamic conditions. One of them is a new scale inhibitor package. The experimental results showed that the new scale inhibitor had the highest inhibition performance (more than 90%). Temperature and mixing ratio had a negligible effect on the scaling inhibition efficiency. The minimum inhibitory concentration of the new inhibitor package was 25 mg/L. Also, the new inhibitor had an enhanced adsorption and desorption rate on the shale rocks.

There are geological and geochemical characteristics of Central and Eastern Pre-Caucasian khadum deposits in this paper. Geographical demarcation of khadum deposits have been made depending on organic matter TOntent, realized and relict generation potential, hydrogen index, catagenesis grade etc. Estimation of hydrocarbon saturation of studied deposits have been made based on complex analysis of obtained data.

Domanic Upper Devonian deposits of the Timan-Pechora petroleum province are the subject of growing scientific and practical interest from the time of its discovery (late 19th century). And, despite the considerable knowledge database on Domanic organic matter have accumulated geochemists, it still requires more detailed study. This article presents the geochemical characteristics of organic matter of Timan-Pechora Domanic source rock using Rock Eval pyrolysis and the kinetic spectra of kerogen decomposition of sedimentary deposits from different parts of the Timan-Pechora basin. The variety of Domanic kinetics by deep strata and by area of the Timan-Pechora basin were analyzed. Dependence of kinetics from sedimentation conditions is shown. Four regional (sublatitudinal and submeridional) 2D basin models were created using of geochemical results. The results of petroleum basin modelling are performed. The sensitivity study of basin models to the kinetic spectrum change was made. It is shown that use of measured Domanic kinetics instead of published in software kinetics significantly affects basin modelling results. Were estimated the volume of generated by Domanic source rock hydrocarbons with use of different kinetics (published and measured). The difference in Domanic generation between these two scenarios is about 70 Mt of oil.

Shale complexes as unconventional sources of hydrocarbons represent serious competition to oil and gas production from conventional fields over the last years. Undoubted success of shale hydrocarbons exploration in North America contribute to the study of shale complexes in many countries, including European ones, such as the UK, France, Sweden, Germany, Hungary, Romania and others. A role in the allocation of shale areas in the Baltic region is given to the Kaliningrad region of Russia. Authors distinguished on the basis of comprehensive analysis including geochemical, geophysical, lithofacial, paleotectonical, paleontological and other studies, the main promising objects for hydrocarbon searches; areas of their distribution and maximum concentrations (in terms of organic matter content and thickness of promising strata) are contoured; the degree of organic matter katagenesis is determined; geochemical reconstructions of oil formation processes in the Paleozoic sediments of the Kaliningrad region are performed; preliminary assessment of hydrocarbon resources is carried out. And authors gave some general recommendations for the development of these resources.