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October 10, 2007
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Home / Issue Archive / 2007 / May #5 / RITEK Develops a Steam-gas Generator Operating on Monopropellant for Production of High-viscous Oil and Bitumen

№ 5 (May 2007)

RITEK Develops a Steam-gas Generator Operating on Monopropellant for Production of High-viscous Oil and Bitumen

High-viscous oil and bitumen are not the most popular types of hydrocarbons at present; however, some countries select these hydrocarbons as an alternative to traditional crude oil and gas.

 

By Elena Zhuk

Particular prospects of their utilization are related to introduction of the technologies of synthetic crude oil production. Almost half of the Canadian oil is synthetic; rates of bitumen recovery and oil production on its basis are increasing steadily in Venezuela. World reserves of high-viscous oil and bitumen are predicted in the amount of approximately 790-900 billion tons, which will enable synthesizing of 400-500 billion tons of liquid fuel. Will the Russian operators be able to make use of this offer of the subsoil? 

"We have to involve in development reserves in low-permeable reservoirs of the Jurassic and Achimov deposits of West Siberia, reserves of high-viscous oil of carboniferous deposits, and also reserves of the Permian deposits of natural bitumen in Tataria", - said Valery Graifer, General Director of the innovation company RITEK. - Development of bitumen reserves is of great importance for Tataria and Bashkiria, but it is impossible to develop the deposits over there in the same way it is done in Canada, because the pay beds are much deeper, and applying this method, operators would have to sacrifice a large volume of arable lands. Modern generation of engineers and scientists has to solve these complicated technical problems".


Correspondent of "Oil & Gas Eurasia" was told by the Department of Scientific and Technical Development of the Company, how RITEK handles production of high-viscous oil and bitumen, and also development of low-permeable reservoirs.  


"High-viscous oil is oil which contains oxygenated component, tar, asphaltenes, such elements as sulfur, and organo-metallic compounds. It is difficult to process this oil, it is hard to pump it due to high viscosity, it flows poorly in the wellbore, and even having large reserves, it is difficult to have high production rates, - said Rafkhat Maksutov, Chief Specialist of the Department. - As at present oil is processed mostly into fuel, lighter types of oil are estimated higher, which can be used for production of gasoline, diesel fuel, etc.  And high-viscous oil is cheaper, it belongs to the category of low-grade hydrocarbons, and there is no chase for this type of oil with the aim of receiving high profit yet. On the other hand, there are areas where such type of oil is recovered utilizing thermal methods, for example, Sakhalin; LUKOIL ("Komineft") has a thermo-carboniferous deposit of the Usinsk field, reserves of which amount to hundreds million tons. High-viscous oil is produced there with the help of surface steam generators. Bitumen deposits can be developed in similar way". Resources of natural bitumen in Tatarstan, being a promising raw material for obtaining an alternative energy carrier, petrochemical products, road and construction materials of high quality, are estimated in the amount of 2-7 billion tons.


Even in the Soviet time, scientists of research association "Soyuztermneft" noticed that oil viscosity increase to about 25-35 CP resulted in at least triple reduction of production, when over 80 percent of oil remained in the reservoir.  At the same time, when oil is heated, its viscosity decreases sharply, and mobility increases, therefore, to improve oil recovery, it was proposed to utilize thermal methods, which so far have no serious alternative for development of the fields of high-viscous oil and bitumen.


The most widely spread thermal methods are steam-thermal and steam-and-gas methods.  "When we inject steam in the well, - commented Maksutov, - the following phenomenon takes place: if generated steam has temperature 300 degrees and pressure 100 atmospheres at the surface, when it comes to the bottomhole, due to heat losses in surface and downhole pipelines, temperature of the heat carrier decreases, steam condenses, and water falls out. Therefore, due to heat losses, fraction of dry steam can appear to be less than half. Thus, now we are developing a method for running a steam-gas generator to the bottomhole and for generating not only steam, but steam-and-gas mixture.  Another reason of low efficiency of steam methods is that being injected to the formation, steam cools and condenses; its volume decreases dozens of times, and therefore, displacing ability of such steam is not high; so, to "push" heat deeper, we inject all combustion products into the formation. Performance index of this process is about 95-98 percent".


The problem of reserves' recovery from low-permeable reservoirs is not less urgent.   Previously oil was replaced by water, but oil pools often have low-permeable solid blocks, and water by-passes them leaving large oil zones not covered. Displacing agent could be much more efficient if it had viscosity similar to that of oil, therefore, at present scientists suggest utilizing a gas component in the displacement process; this component, in contrast to water, is hydrophobic and easier penetrates into thin pores.  


The technology of water-and-gas treatment, which is already applied by some Russian companies, is realized by RITEK in a special way. According to professor Maksutov, "We utilize associated gas at pressure close to atmospheric one (maximum 4-5 atmospheres) for displacement, but we need to get 300-400 atmospheres. As the Company has many small fields, it would be uneconomical to fabricate a large gas treatment unit. The matter is that we need to inject all produced gas into the formation, but this gas contains rich fractions. During compression, some sediment settles which cannot be compressed, thus, after each stage, it is necessary to drain condensate as it is difficult to re-inject it into the formation, and there is no appropriate equipment for that. Besides, in our case we deal with high-viscous oil with low gas-oil ratio".   


RITEK specialists believe that new methods will find wide application in the Russian oil fields. If we consider application of steam-and-gas methods, the Russian Federation has over six billion tons of remaining booked reserves of high-viscous oil of А+В+С1 categories, major part of which is located in Tyumen Oblast and Republic of Tatarstan.  In Tatarstan, high-viscous oil makes over 89% of total reserves of the Company, which illustrates general forecast numbers: it is predicted that by 2020, production of high-viscous and sour oil in the republic will reach approximately two-thirds of the total volume of production of so-called "black gold". At the same time, dozens of billion tons of Russian oil could become an object for application of the water-and-gas treatment technology.  


At present, these technologies are at the testing and acceptance stage. Water-and-gas treatment method is being implemented in the Vostochno-Perevalnoye field; a project for the Sredne-Khulymskoye field is being finalized. In the course of the project realization, all associated gas will be re-injected to the formation, which will help to stop gas flaring. The program of the development tests of steam-and-gas methods has been realized since the beginning of 2006 at the proving ground in Krasnodar where conditions close to wellbore ones at the depth of 100 m are simulated. "If it becomes necessary to fix something in the real situation at the depth of 1000 meters, we shall have to pull out thousands of meters of pipes, etc., - explained R.Maksutov. - Testing of the method on wells in Tatarstan is scheduled for the second half of this year".


Rafkhat Maksutov has been working on development of thermal methods of oil recovery enhancement for about thirty years. "Such a steam-generating complex utilizing a monopropellant is being developed for the first time", - said Gennady Orlov, Deputy Head of the Department of Scientific and Technical Development of RITEK. Monopropellant ("know-how" of the Company) is a water solution of nitrates and is utilized for generation of heat and gas, i.e. injected solution turns into water steam, nitrogen and CO2.


The new unit is designed to facilitate production of high-viscous oil and natural bitumen. "The first period of bottomhole steam generator development is related to 1970-1980.  Then such problems existed as necessity of utilizing compressors, high expenses. Today specialists of RITEK put new life into this idea. In 2004, Rafkhat Maksutov recalled the idea of monopropellant and put it forward again.  Compared to steam injection from the surface, expenses on utilization of a bottomhole steam generator are significantly lower. Field tests will provide definite numbers. Certainly, previously we also had some developments. Development of absolutely new technologies and equipment is a risky and expensive thing. The greater is expected effect, the higher is the risk, as a rule.  The first such unit fabricated by us was working on hydrogen fuel. By the way, it is in operation now!", - said Orlov.


 "I think that RITEK spends more money (in percent of the profit) on research work compared to many large companies. It handles the fields, which are small in reserves and located far from the industrial centers, and, therefore, their development is uneconomic. - Orlov says. - Multi-pay zones, marginal wells, high-viscous oil... At present, if companies have not much money available, they do not seriously undertake development of these areas. In my opinion, the characteristic feature of our activity is that the Company is developing integrated technologies, such as water-and-gas, steam-and-gas treatment, and so-called "intelligent" field. These are front-lines of our activity".


The Company included such areas of activity as designing of equipment and technology for steam-and-gas treatment of beds containing high-viscous oil reserves, designing of equipment and technology for efficient associated gas utilization, establishment of a system of intelligent management of field development in a special section of top-priority innovation programs described in the "Concept of Long-term Program of Scientific and Technical Development for the Period of 2006-2015".


RITEK's contribution in the development of cutting-edge technologies was recently acknowledged by the Federal Agency for Science and Innovations, that honoured the company as the winner of the competition "Creation and implementation of an innovative technological complex for extraction of hard-to-recover and non-traditional raw materials (kerogen, oil-bearing sand, high-viscous oil)". In partnership with the Gubkin State Oil&Gas University and the scientific and technological corporation ITIN, the Company was awarded a state contract in the amount of 210 mln rubles for the next three years.

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