Field development. Reservoir engineering. Production
The article discusses the effectiveness of the method to increase the productivity of wells when they are treated with aqueous solutions of binary mixtures. After injection of the solution into the formation, an exothermic reaction of interaction between the components of the binary mixture accompanied by the evolution of gases is initiated. The impact on the bottomhole zone of oil wells of heated chemical reaction products is combined and reduces to three phenomena: the warming of the rock and the oil in it; cleaning of the bottomhole zone from paraffins, resins and colmatizing sediments; expansion of natural cracks and the appearance of artificial cracks. As a result of the treatment near the well, two regions are formed: with increased conductivity and high temperature (where the viscosity of the oil decreases). The sizes of the areas may not coincide. Each region contributes to an increase in the productivity of the well. In the work by methods of mathematical and numerical modeling, the processes of thermal effect of chemical reaction products to the formation are investigated and the increase in the flow rate of the well is estimated due to the decrease in the viscosity of oil. A mathematical model of the reacting process for a binary mixture in a porous media, its filtrations and influence on a reservoir system is proposed. The numerical solution of the problem was carried out on the basis of the OpenFOAM open integrated platform. The results of numerical modeling of the reaction process of a binary mixture and the subsequent extraction of oil from a heated reservoir are presented. Estimates of the temperature increase and the size of the heating region during the exothermic chemical reaction in the pore space, as well as the expected increase in oil production and the duration of the effect were obtained. The cases of different concentration of active substances are investigated. The high economic efficiency of the method for increment well production is shown
Many oil deposits of Russia quickly become mature production fields having an adverse effect on the economic feasibility of their development. This fact makes the oil companies improve methods and recovery techniques of these fields to lower the costs of oil reservoir engineering.
Large oil companies apply for well clusters modernization to decrease well service costs. With time the extracted oil becomes more and more viscous therefore there is a problem of decreasing this viscosity. The article considers the transition from the scheme of one-line crude oil gathering system to separate gathering. The modernized cluster has a special water feed station providing a decrease in oil viscosity up to the values comparable to water viscosity by injecting purified and treated water from water-injection pumping station.
The price of the equipment after modernization is more expensive due to a large number of expensive motor operated valves, but it is justified by metering units’ maintenance with non-stop production. Also, the maintainability of the equipment is improved, because the most of the installations are on the surface now. The repair teams do not need to remove faulty items from the ground for troubleshooting. The corrosion protection of the equipment is also improved because the modernized cluster is supplied by inhibiting corrosion protection of pipelines made by chemical injection skid.
Thus, the optimization of oil and gas well clusters organization could become an expensive enterprise, but it is quite justified as in the long term it is favourable.
One of the most important factors, which define the efficiency of sucker rod pump operation, is the filling coefficient of rod pump. The dominant influence on the rate of filling of liquid of the rod cylinder exerts the gas content in the well output and also the presence of the volume, which is placed between suction and discharge valves of the pump in the extreme bottom position of plunger and named as harmful (dead) space of sucker rod pump.
In the paper the processes, which occur in the under–plunger space of rod pump during pumping of gas–liquid mixture, are considered and the influence of the volume of dead space on the character of these processes is estimated quantitatively. The analysis of the known models is presented, which describe the hydraulics of sucker rod pump, and a model is proposed, which accounts for the processes of mixture compressibility in the under–plunger space and the equilibrium processes of gas dissolution and extraction from oil in details. On the base on the constructed mathematical model the method of estimation of limits of possible volume of dead space change is proposed, which allows to keep the filling coefficient value close to the maximum level at given conditions.
Currently, the share of produced together with oil in the fields gas usage does not reach the levels determined at the legislative level. According to official data, no more than 80% of the produced gas is used advantageously (the normative value is 95%). Combustion of associated petroleum gases is accompanied by the consumption of oxygen and the release of excess heat. This is detrimental to the ecology of the Earth, contributes to the greenhouse effect.
On the other hand, the combustion of gas produced with oil is irrational in the use of raw materials and creates lost commercial profit. The article considers the direction of utilization of associated gas as a raw material for obtaining high-quality motor fuel and other hydrocarbons, including synthetic oil. The process consists of autothermal reforming and the Fischer-Tropsch process.
A brief review of the experience of using such plants abroad is presented. The characteristics of plants for the production of ultra-clean diesel fuel with the use of APG gas caps for the fields of the Near Abroad of Russia are used as raw materials for APG.
The results of the analysis of the economic feasibility of the installation with a minimum consumption of associated gas of 50 million m3/year are shown. The main technical parameters of the plant are presented: productivity for the main product – diesel ultrapure fuel of the Arctic grade – and associated hydrocarbon products.
The dependence of the main performance indicators of the plant on its main product productivity is constructed. The range of productivity from 7000 tons/year to 141500 tons/year is considered. It is shown that with an increase in the capacity of the installation, the payback period, taking into account the discounting, is reduced, reaching 4 years at maximum power. At the same time, CAPEX costs about 180 million US dollars.