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Date submitted2022-06-20
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Date accepted2023-01-10
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Date published2023-08-28
Laboratory, numerical and field assessment of the effectiveness of cyclic geomechanical treatment on a tournaisian carbonate reservoir
Results are discussed for evaluation of effectiveness of the cyclic geomechanical treatment (CGT) on a Tournaisian carbonate reservoir. Analysis of laboratory experiments performed according to a special program to assess permeability changes for Tournaisian samples under cyclic changes in pore pressure is presented. The main conclusion is the positive selectivity of the CGT: an increase in permeability is observed for samples saturated with hydrocarbons (kerosene) with connate water, and maximal effect is related to the tightest samples. For water-saturated samples, the permeability decreases after the CGT. Thus, the CGT improves the drainage conditions for tight oil-saturated intervals. It is also confirmed that the CGT reduces the fracturing pressure in carbonate reservoirs. Using flow simulations on detailed sector models taking into account the results of laboratory experiments, a possible increase in well productivity index after CGT with different amplitudes of pressure variation was estimated. Results of a pilot CGT study on a well operating a Tournaisian carbonate reservoir are presented, including the interpretation of production logging and well testing. The increase in the well productivity index is estimated at 44-49 % for liquid and at 21-26 % for oil, with a more uniform inflow profile after the treatment. The results of the field experiment confirm the conclusions about the mechanisms and features of the CGT obtained from laboratory studies and flow simulations.
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Date submitted2020-06-16
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Date accepted2020-11-09
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Date published2020-12-29
Investigation of probabilistic models for forecasting the efficiency of proppant hydraulic fracturing technology
To solve the problems accompanying the development of forecasting methods, a probabilistic method of data analysis is proposed. Using a carbonate object as an example, the application of a probabilistic technique for predicting the effectiveness of proppant hydraulic fracturing (HF) technology is considered. Forecast of the increase in the oil production of wells was made using probabilistic analysis of geological and technological data in different periods of HF implementation. With the help of this method, the dimensional indicators were transferred into a single probabilistic space, which allowed performing a comparison and construct individual probabilistic models. An assessment of the influence degree for each indicator on the HF efficiency was carried out. Probabilistic analysis of indicators in different periods of HF implementation allowed identifying universal statistically significant dependencies. These dependencies do not change their parameters and can be used for forecasting in different periods of time. Criteria for the application of HF technology on a carbonate object have been determined. Using individual probabilistic models, integrated indicators were calculated, on the basis of which regression equations were constructed. Equations were used to predict the HF efficiency on forecast samples of wells. For each of the samples, correlation coefficients were calculated. Forecast results correlate well with the actual increase (values of the correlation coefficient r = 0.58-0.67 for the examined samples). Probabilistic method, unlike others, is simple and transparent. With its use and with careful selection of wells for the application of HF technology, the probability of obtaining high efficiency increases significantly.
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Date submitted2014-11-15
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Date accepted2015-01-11
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Date published2015-10-26
On the necessity of taking into consideration the increment of the growing stock in cadastral valuation of lands of forest fund
- Authors:
- V. F. Kovyazin
Currently there are no methods of cadastral valuation of forest land although the area covers 2/3 of the territory of the Russian Federation. In 2002, the Federal Land Inventory Service of Russia proposed a method but it failed to find practical use due to the complicated calculation of the cadastral value according to the Faustmann formula and lack of open access to some information about the forest fund and was totally abolished seven years later. There were several reasons for abolishing the method and the main reason was lack of methods to predict a supply of wood to the age of maturity when the cadastral assessment was carried out in the plantations under the age of main felling. The author proposes to take into account the current growth rate of the growing stock per year on one hectare of land in the cadastral evaluation of forest fund lands. Based on the increment of the growing stock it is possible to construct a mathematical model of changes in the forest reserve to the age of maturity. The author suggests using the existing forest inventory materials to build the model. By updating existing data you can obtain any inventory indices including the growing stock in different age plantations. The resulting inventory of plantations at the age of maturity is recommended for cadastral valuation of the forest fund lands. The calculation of the cadastral value of forest land for one taxation quarter with and without current increment of the growing stock is given and the difference is 37 %.