Field development. Reservoir engineering. Production
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.
This research is relevant as the development of world energy over the past decades is characterized by increased production and consumption of natural gas. One of the leading gas producing countries is Russia, which accounts for more than 25% of the world’s total gas production. In the Energy Program of the Russian Federation, by 2020, the planned volume of gas production will be 700 billion m3. The development strategy of the gas industry provides for the extraction of residual geological reserves. All these aspects are pushed to create new and effective technologies for gas preparation, as well as modernization of existing technological processes and equipment for gas preparation.
Every year, the role of gas in the global fuel and energy balance is becoming increasingly important. Thus, in 2002, global production amounted to approximately 2.800 billion m3. Of these, only 522 billion cubic meters of gas were produced by Russia’s Gazprom. The growth of gas production in Russia by 2005 was about 5%.
The state of the oil and gas industry is characterized by low automation, the use of obsolete and worn-out equipment, a decrease in gas production in exploited deposits, an ever-increasing remoteness of developing deposits, and so on. In conditions of increased competition from foreign producers, modernization of gas engineering and increasing the efficiency of gas production are vital for ensuring energy security and stable economic development of the country.
The article discusses the problem of exploitation of gas fields, at a late stage of development. The operation is complicated, because of the accumulation of condensation and formation water, a limited number of technological processes are used, as a result of which the productivity of the wells decreases or irreversible gas losses occur during process blowdowns.