No 13 (2014)
- Year: 2014
- Articles: 10
- URL: https://ered.pstu.ru/index.php/geo/issue/view/128
Abstract
At the time when oil and gas prospecting on the territory of the Kogalymneftegaz business unit becomes more challenging advanced models to forecast oil and gas content of the traprock acquire particular economic value. At present there are some data both on the areas containing hydrocarbon accumulation and those where prospecting drilling was performed but no hydrocarbons discovered. On the basis of the statistic material available it is suggested to develop a method of forecasting oil and gas content using probabilistic statistical models. Geologic mathematical models are constructed by means of comprehensive application of the correlation, discriminant and regression analyses. This approach transforms a multidimensional problem into a one-dimensional problem. This allows interpreting geologic and statistical data with higher quality. In doing so, parameters are used in comprehensive manner, which conditions high reliability of the probabilistic statistical models to forecast oil and gas content. All these areas have to be described by the same parameters which should be calculated prior to deep prospecting drilling. This allows building probabilistic statistical models which in practice may be used for evaluation of an oil and gas content of the undeveloped traprocks. Thanks to the method devised a traprock drilling priority may be determined, normalising oil production on the territory of Kogalymneftegaz.
Keywords: hydrocarbons, oil and gas content, forecast, regression equation, correlation relationship, coefficient of correlation, parameter informativeness, linear discriminant analysis, multidimensional regression analysis.
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Abstract
Capabilities of the modern software toolkit IRAP RMS by ROXAR are exploited: tools of a stratigraphic, lithologic and petrophysical modelling, allowing three-dimensional parameters of lithology, the oil-saturated volume Kп, Kн, maps of effective and effective-oil-saturated layers, as well as the results of a hydrodynamic modelling. To evaluate correctness of the three-dimensional models built a comparison of geological and hydrodynamic characteristics of the deposits is required. The problem was solved by the elements of mathematical statistics, i.e. a step-by-step discriminatory analysis for which variables were selected on the basis of the 3D modelling results presented in the form of geological and hydrodynamic characteristics of the object explored. The analysis generated probabilistic parameters for identifying observations as belonging to the main development site – the deposit near the well 1 , for geological (Рг.п) and hydrodynamic (Ргд.п) deposit parameters, coupled with the integrated probabilistic parameter Рк. Additionally, probability maps and scattering graphs were produced which made it possible to identify two main areas: 1) one with the observations belonging to the Nozhovskoye upheaval deposit, near the well 1; 2) another with the observations not belonging to the Nozhovskoye upheaval deposit.
Keywords: deposit, pay bed, upheaval, seismic survey, 3D geological model, lithologic modelling, reservoir, cap rock, field, petrophysical modelling, estimating of crude oil, 3D hydrodynamic model, correlation coefficient, discriminatory analysis, probability map.
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Abstract
Drawing on the research performed and the analysis of the control of hydrofracturing parameters, a problem is being solved of designing an automated measuring system making use of instruments and tools of inertial navigation which permit a higher accuracy of measuring error angles of mounting the plates for research equipment, considering dynamic measurement error. Enhanced features of the measurement system are provided by additional measurement of spatial angular deviations and azimuth misalignment angle of the plates.
The paper evaluates accuracy parameters of spatial angular deviations of the plates for GIS-tools from calibration errors, installation errors, tilt angles, initial tool misorientation. It is suggested to apply methodology of measurement system development to solve the problem of orientation of tiltmeters, instruments for control and monitoring of fracture growth following hydrofracturing, taking account of tolerances not considered during hydrofracturing. The methodology allows solving the problem of assuring accuracy in measuring parameters of hydrofracturing due to proper tiltmeters installation and orientation (during microseismic logging and measurement of deposit's deformation angles) both on daylight surface and inside a well; due to meeting requirements to set tiltmeters into a null (initial) position and the position in which their mutually perpendicular axes (X and Y) are precisely aligned with the cardinal directions. The method to control angle-error parameters of the plates may be of use to machine construction, machine-tool manufacture, geology and geophysics, oil-and-gas well construction.
Keywords: measuring navigation heads, tiltmeter, well, coordinate inaccuracy and receiver orientation, accelerometer, orientation, spatial azimuth and horizon angle deviations, azimuth misalignment angle of the plates for the equipment to control and analyze a fracture growth.
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Abstract
Development of the producing wells leads to gradual degradation of reservoir properties of the bottom-hole area and skin factor increase. Choking the bottom-hole area is mainly caused by formation of asphaltene-resin-paraffin deposits and clogging of pore channels by rock particles when a fluid moves towards the borehole bottom. Different stimulation techniques are implemented in order to improve pressure communication between the reservoir and the well, recover bottom-hole area permeability and reduce the skin factor. Oil well acidizing is the most common treatment. To stimulate oil extraction from carbonate reservoirs hydrochloric acid-based compounds are widely applied. There exist the optimum parameters that allow performing oil well acidizing with ultimate efficiency. A rate of acid compound injection into the bottom-hole area is one of such parameters. The optimum injection rate to produce a high-conductivity channel requires a minimum amount of acid compound.
The paper explores the effects of core sample characteristics and laboratory test conditions on the sample permeability following acidizing. The results of laboratory tests of the effects of acid compounds on the samples of carbonate productive sediments located at Perm krai deposits have been analyzed with a step-by-step regression analysis. A number of parameters affecting the acidizing efficiency have been determined. It is proved that the conclusion about the critical (optimum) rate, formulated in our previous paper, has a significant statistical justification.
Keywords: carbonate reservoir, bottom-hole area, acid compound, core sample, regression analysis, optimum parameters, injection rate, pore volume.
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Abstract
Improving efficiency of the reservoir pressure maintenance is an issue of current importance for oil producing companies. Cyclic fluid injection is one of the effective methods to improve water energy use by generating the unsteady pressure field within the reservoir, resulting in a better oil recovery. Despite simplicity of the technology, in certain circumstances it may be ineffective.
The article presents the method to produce the static model which allows estimation of probability of the positive effects from cyclic fluid injection, taking account of geological and technological conditions. The analysis of production facilities applying cyclic fluid injection was carried out for oil fields located in Perm krai. Calculations of technological efficiency of unsteady flooding were performed in two ways: the first implies plotting characteristics of the Maksimov's oil drive in the modified coordinates; the second draws on a diagram of specific well discharge well versus the current oil recovery factor set forward by Lysenko. The statistic analysis revealed geological and technological parameters which have the greatest impact on cyclic fluid injection effectiveness. For the deposits developed with reservoir pressure maintenance the forecast models are built that enable to evaluate probability of positive technological effects of the cyclic injection applied.
Keywords: cyclic injection, sweep efficiency, driving-out parameters, technological effect, linear discriminant function, probabilistic estimate, statistical model, enhanced oil recovery, reservoir pressure maintenance, formation heterogeneity, specific oil production.
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Abstract
The Nozhovskaia group of oil fields is located in the south of Perm krai and is operated by the Lukoil-Perm company. To reveal complications in development of these fields, the analysis of complicating factors , namely geological and physical characteristics of the reservoir, physico-chemical composition of the oils was performed. The stages of development of the fields of the Nozhovskaia group were defined. An analysis was done of lift methods sequence in active wells and the main reasons for well servicing, as well as of the complicated wells making 67 % of the total well stock. The main complications relate to asphaltene-resin-paraffin deposits (ARPD) and highly viscous water-oil emulsions.
The following complicating factors in development of the Nozhovskaia group of oil fields were revealed: a low permeability of producing reservoirs, low reservoir temperatures, high well stream watering, extra high-viscosity oil with high content of paraffins, sulphur and non-hydrocarbon components. The dominating complication is caused by intensive formation of ARPDs. The main method to control ARPDs draws on paraffin inhibitors that demonstrate the best cost efficiency and technical performance. Cleaning of the downhole pumping equipment and pipes from ARPDs is carried out by hot-oil and resolvents. To optimize the costs of well inhibitor protection a detailed evaluation of the used inhibitors efficiency is required, as well as special selection of new inhibiting compositions with demulsifying effects and field tests of innovative methods of their application by pumping them into a well face and bottom-hole area.
Keywords: producing well, lift method, asphaltene-resin-paraffin deposits, oil extraction complications, reservoir and fluid properties, paraffin inhibitors.
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Abstract
The quality of designing locomotives for mine railway is conditioned by extensive and in-depth knowledge of the processes occurring in different units and components parts, by ability to make the calculations required and select proper parameters of the locomotive. A modular approach to locomotive design allows constructing locomotives of the different adhesive weight and with different motive power arrangements, requiring fundamental scientific justification. Hence the need to explore the main regularities in evolution of dynamic properties of the system 'underframe – drive – track'. The task to investigate fluctuations of drive segments of a mine locomotive, as well as nature and conditions of the tractive and breaking effort realisation comes to multivariate calculations of a multimass system under variable numeric input values of its parameters. Finding a range of stable motion of the locomotive hauling a cart set was performed by solving a differential equation system. Mathematical model parameters were found by calculations made in modern CAD-CAL applications for the built 3D-models that represent actual inertia, geometric and kinematic parameters of the mine haulage vehicle.
The basic construction of the E10 articulated locomotive designed and manufactured with the participation of the authors has proven cost effectiveness of the technical solutions suggested. Among the factors of cost effectiveness there were reduction of battery supply, decrease of capital and operational costs, increase of locomotive availability factor, improved safety on grades of 30–50 ‰.
Keywords: sectional mine locomotive, drive, mechanical operations, traction, breaking, tractive section, safety, output, traffic, interchangeability, mathematical model, cost effectiveness.
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Abstract
Outburst hazard control is performed by acoustic signals during treatment and operation of the face equipment in the working area using the APSS-1 unit and programming and computing suite. Real-time processing of the signal obtained was performed on the PC following the algorithm by Makiivka Research Institute. The analysis of the results of mine studies has shown that the warning 'Danger' in the unhandled area of the coal bed was reported at a rate of 0.03 time/m, or once per each 33.3 m of face advance; in the area processed by hydrodynamic impact no 'Danger' warning was received. The 'higher risk' warning in the unhandled area was reported at 0.14 time/m, or once per 7.1 m of face advance; in the processed area at 0.03 time/m, or once per 33.3 m of advance, which is 4.7 times more rare. Research on hydrodynamic impact effects on outburst hazard factor for the coal bed located at the 24th western inclined face has showed that as the length of the console of the main and immediate roof grew the value of outburst hazard factor went constantly up. Prior to face penetration into the processed area 30 out of 1000 measurements reported outburst hazard factor surpassing 3. The highest value made 4.8 (a critical value for the given conditions kв = 3). Within the areas from PK68 to PK67+6 there were registered twelve highest values. Coal extraction from the processed area produced an outburst hazard factor of 2.1 (following 450 measurements), while the average value on a section 220 m long, from PK56 to PK34, made 0.84.
Hydrodynamic impact improves dramatically a condition of a coal bed in terms of outburst hazard, which is conditioned by lower content of methane, coal wetting and roof sheeting favouring even deformations and rock pressure redistribution.
Keywords: intensification of coal bed degassing, production wells, hydrodynamic impact, methane desorption, outburst hazard, relieved area, degassing factor.
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Abstract
55 years after the Starobinskoye potassium salts deposit was put into service significant reduction of mineral reserves in active mines has been noticed. In some years to come it may lead to gradual extinction of a subsurface ore extraction. To maintain current performance new possibilities are being investigated in the mines, aimed at enhancing the raw materials base. Technical solutions for mining reserves of the new fields are being assessed. Nevertheless, the age of the active mines at Belaruskali JSC may be prolonged by mining the resources left in panel barriers (safety pillars) which width varies between 40 and 200 m, depending on the specific mines.
The article presents the results of assessment of feasibility of mining the resources stored in safety pillars. A possibility of re-entry of the aged mine workings operated 20 to 30 years ago by means of repair-and-renewal operations has been explored. It is established that the age of the restored mine workings, even in the absence of additional measures of protection and support, will be not less than three years. This makes their re-entry possible and reduces the cost of preparatory work in mining the pillars previously left undisturbed.
Keywords: Starobinskoye potassium salts deposit, abandoned longwall, rock fall, discharge area, drift boundary failure, working repair, safety pillar, convergence of working walls, deformation rate, distortion, working age.
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Abstract
To prevent the process of condensation in shallow underground workings, mining companies implement the air conditioning system (ACS). The existing ACS consume enormous amounts of electricity, hence many businesses refuse to apply them. However, without ACS problems with moisture precipitation occur. This aggressive medium is particularly dangerous for an electric equipment, as well as explosion-resistant equipment. The paper outlines a concept of the ACS design based on positive overall natural draft between two mine shafts, generated by heat convection. This phenomenon is due to the fact that a warmer (lighter) air tends to lift up while a cooler to go down. In doing so, air is fed to the underground part of a mining enterprise in amounts exceeding standard requirements. Such a design allows switching an operation mode of the main fan to lower pressures, thus reducing energy consumption. The saved electric energy can be used to power ACS. In this layout energy efficiency of air handling increases considerably, while problems of moisture precipitation in the underground mine space are solved.
Keywords: air conditioning system, energy efficiency, evaporator, condenser, main fan, overall natural draft, intake shaft.
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