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Results
Evaluation of the efficiency of steam and solvent composition injection based on the results of pilot field tests (Russian)
Khisamov, R. S. (PJSC TATNEFT) | Zakirov, I. S. (Almetyevsk State Oil Institute) | Zakharova, E. F. (Almetyevsk State Oil Institute) | Ganiev, B. G. (PJSC TATNEFT) | Amerkhanov, M. I. (PJSC TATNEFT) | Akhmetzyanov, F. M. (PJSC TATNEFT)
To date significant reduce of bituminous oil viscosity is the only way to start its production. Among the most common injected agents is steam, solvent or their combinations. When developing bituminous oil reserves, due to their high viscosity, modern approaches are required, from creation of new solvent compositions to implementation of cost-effective technologies for natural bitumen production. Cyclic steam – solvent stimulations results in residual bituminous oil recovery and increase of bituminous oil displacement efficiency. The article presents the results of pilot tests of steam and solvent composition injections. The solvent composition was developed at Almetyevsk State Oil Institute during the implementation of the project with federal support in 2017-2020 to increase the efficiency of bituminous oil reserves development in marginal zones of deposits under conditions of high reservoir heterogeneity. Previously laboratory studies ware carried out and solvent composition was developed. During filtration tests this solvent effectively reduced oil viscosity and prevented asphaltene precipitation in the reservoir, resulting in an increase of displacement efficiency. These results were fully confirmed in pilot tests. According to the results of pilot tests injection of developed solvent composition into steam-cycle wells increases oil production rate of steam-cycle wells due to additional oil recovery with the solvent in comparison with pure steam injection. Moreover, it was found that the injected solvent spread laterally through the reservoir and reached neighboring pairs of injection and production wells operating in the steam-gravity drainage mode. As a result due to solvent injection areal sweep efficiency increases and additional oil reserves are involving into development.To date significant reduce of bituminous oil viscosity is the only way to start its production. Among the most common injected agents is steam, solvent or their combinations. When developing bituminous oil reserves, due to their high viscosity, modern approaches are required, from creation of new solvent compositions to implementation of cost-effective technologies for natural bitumen production. Cyclic steam – solvent stimulations results in residual bituminous oil recovery and increase of bituminous oil displacement efficiency. The article presents the results of pilot tests of steam and solvent composition injections. The solvent composition was developed at Almetyevsk State Oil Institute during the implementation of the project with federal support in 2017-2020 to increase the efficiency of bituminous oil reserves development in marginal zones of deposits under conditions of high reservoir heterogeneity. Previously laboratory studies ware carried out and solvent composition was developed. During filtration tests this solvent effectively reduced oil viscosity and prevented asphaltene precipitation in the reservoir, resulting in an increase of displacement efficiency. These results were fully confirmed in pilot tests. According to the results of pilot tests injection of developed solvent composition into steam-cycle wells increases oil production rate of steam-cycle wells due to additional oil recovery with the solvent in comparison with pure steam injection. Moreover, it was found that the injected solvent spread laterally through the reservoir and reached neighboring pairs of injection and production wells operating in the steam-gravity drainage mode. As a result due to solvent injection areal sweep efficiency increases and additional oil reserves are involving into development.
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
To produce heavy crude oil and natural bitumen, thermal recovery methods have been commonly used. According to PJSC TATNEFT, for fourteen years of development of heavy oil fields, more than 45 million tons of steam at temperature of more than 200°C has been injected into subsurface formations. One of the most effective technologies for producing ultra-viscous crude oil and natural bitumen is the steam assisted gravity drainage (SAGD) process. To ensure high efficiency and safety of the SAGD technology, an operator must control the SAGD process and perform a large bulk of chemical-analytical and other types of analyses of produced fluids. The paper discusses possible negative aftereffects of SAGD termination following the lengthy period of steam injection. In SAGD, the injected steam serves the two purposes: fills the void space left by the heavy oil, and maintains the temperature in the steam chamber. The latter purpose is very important, since cooling of the steam chamber may lead to decrease of the reservoir pressure and the abrupt steam condensation, which, in its turn, may result in pay rock deformation, extensive land surface subsidence, behind-the-casing flows, contamination of the overlying formations, including aquifers. Obtaining analytical estimates of the steam mass to maintain the steam chamber temperature is an important tool of the SAGD process control, along with the 3D thermohydrodynamic modeling. The authors present an analytical technique to separate the injected steam into the steam mass to maintain the steam chamber temperature and the steam mass to provide the steam chamber growth. The technique is based on the material balance equation and the estimate of the steam-condensate mixture density in reservoir conditions.
- Europe > Russia > Volga Federal District > Tatarstan > Volga Urals Basin > Ashalchinskoye Field > Ufa Formation (0.99)
- Europe > Russia > Volga Federal District > Tatarstan > Volga Urals Basin > Ashalchinskoye Field > Sheshminskiy Formation (0.99)
Assessing the applicability of chemical agents for the development of high and ultra-high viscosity oil fields of Tatneft PJSC (Russian)
Amerkhanov, M. I. (Tatneft PJSC) | Beregovoi, Ant. N. (TatNIPIneft) | Rakhimova, Sh. G. (TatNIPIneft) | Knyazeva, N. A. (TatNIPIneft) | Ziatdinova, R. Sh. (TatNIPIneft) | Razumov, A. R. (TatNIPIneft)
The Republic of Tatarstan possesses considerable high- and ultra-high viscosity oil reserves. The latter are localized at relatively shallow depths (primarily up to 200 m), but fall under the category of hard-to-recover due to high viscosity reaching in-situ as high as 100 Pa·s and even higher. High-viscosity oil fields are developed under conventional natural drive utilizing the reservoir energy or under waterflood, that fail to provide high oil recovery factors. Ultra-viscous oil is recovered using thermal methods. Steam-assisted gravity drainage is the most extensively used method in Tatneft Company. Although this technology has already proven its efficiency, various factors affect ultra-viscous oil production in the Company: complex geological structure of the fields (small thicknesses, heterogeneous structure with low-permeability shale interlayers, vertical and horizontal variations in oil saturation and permeability, moving oil-water contact); vertical viscosity variations; substantial costs associated with steam generation and injection; considerable expenses on treatment of produced fluid. These factors are detrimental to the economics of ultra-viscous oil field development projects that often are rendered unprofitable without tax incentives. Chemical (thermal-chemical) treatments may improve economic efficiency of high- and ultra-high viscosity oil production, when heat and steam generation does not require considerable costs. In light of the above, assessment of applicability of chemical agents and compositions thereof to enhance the efficiency of high-viscosity field development becomes of utmost importance.
Improved production performance of heavy oil reservoirs with compacted and shaled-out interlayers (Russian)
Zaripov, A. T. (TatNIPIneft) | Razumov, A. R. (TatNIPIneft) | Beregovoy, Ant. N. (TatNIPIneft) | Knyazeva, N. A. (TatNIPIneft) | Vasilyev, E. P. (TatNIPIneft) | Amerkhanov, M. I. (Tatneft-Dobycha)
Currently underway is commercial production of extra-viscous oil in the fields of the Republic of Tatarstan using steam-assisted gravity drainage (SAGD) technique. A large amount of updated field data obtained during appraisal drilling as a preparatory stage for extra-viscous oil production operations, systematization of geophysical and geological data with rock typing, paleogeographic reconstructions and modeling enabled identification of the zones exhibiting oil saturation heterogeneity and complex geological structure. A significant factor interfering with the production of extra viscous oil is the presence of shaled-out interlayers associated with lack of reservoir continuity, when a sharp change of facies types from predominantly sandstone to interbedding clays, siltstones and sands is observed in shallow marine shelf conditions on bar slopes and barrier islands. Prior to operation of horizontal wells drilled in such zones a number of issues shall be tackled. Firstly, it is necessary to select optimal compositions depending on rock mineralogy, calculate the required injection volume and concentration of chemical agents, which will also depend on rock characteristics (the clay and carbonate component), such that the injection volume be large enough to provide the desired benefits, on the one hand, and not too large to favor the formation of direct flow channels between parallel horizonal (injection and production) wells which will further lead to steam breakthrough. Negative effects on tubing string and perforation interval shall be minimized through selection of optimal composition and treatment strategy. To date, combined efforts of specialists from research and production departments of Tatneft Company resulted in development of the technology that mitigates detrimental effects of the above-mentioned factors during the development of extra-viscous oil reservoirs using SAGD technique.
- Geology > Petroleum Play Type > Unconventional Play > Heavy Oil Play (1.00)
- Geology > Geological Subdiscipline (0.90)
- Geology > Rock Type > Sedimentary Rock (0.89)
The PDF file of this paper is in Russian. Currently, pilot project on heavy oil production by SAGD technology is being implemented in Tatarstan fields. An essential factor complicating heavy oil production is presence of oil-water transition zones penetrated by production wells. Other adverse factors include presence of gas and water zones, lack of distinct reservoir continuity, mudded interlayers, high variability of OWC depth over short intervals in new fields and uplifts. All these factors result in either man-induced or natural migration of underlying mineral waters into the overlying fresh water aquifers. At the same time, a number of issues should be addressed prior to production operations, including selection of optimal composition based on rock mineralogy in the interwell space, and calculation of the required injected amount and concentration of chemicals, which will depend on reservoir rocks (clay and carbonate content). On the one hand, the amount of the injected composition should be sufficient for efficient treatment of the interwell space; on the other hand, it is necessary to prevent channeling between parallel horizontal wells (injector and producer), which will eventually result in steam breakthrough. It is critical to solve the problem of minimizing the adverse impact on the tubing string and the screen pipe by selecting an optimal composition and stimulation option. Some engineering aspects must also be addressed concerning treating either the entire horizontal wellbore or the selected borehole sections. This will require application of emulsion compositions. To date, due to concerted efforts of engineers from scientific and production units of Tatneft PJSC, a suite of technology has been developed to significantly mitigate the negative effect of the above-mentioned factors when producing heavy oil by SAGD method.
- North America > United States (0.29)
- Europe > Russia > Volga Federal District > Republic of Tatarstan (0.24)
Development of chemical system to remove inorganic scale from oilfield equipment during heavy oil production (Russian)
Khisametdinov, M. R. (TatNIPIneft, RF, Bugulma) | Ganeeva, Z. M. (TatNIPIneft, RF, Bugulma) | Zholdasova, E. R. (TatNIPIneft, RF, Bugulma) | Nuriev, D. V. (TatNIPIneft, RF, Bugulma) | Amerkhanov, M. I. (Tatneft PJSC, RF, Almetyevsk)
The PDF file of this paper is in Russian. One of the most common ways of carbonate scale removal is cyclic flushing of pumps and filters with hydrochloric acid which is noted for its high dissolving capacity and low price. Application of this technique requires considering the effect of high reservoir temperatures which intensify reactivity of typical acid solutions and reduce the efficiency of scale inhibitors, resulting in substantial increase of downhole equipment corrosion rate. Nonaggressive chemicals are available that are used for dissolving inorganic salts of calcium, magnesium, and iron, while simultaneously preventing their re-deposition by aggregating cations in chelates. One of such chemicals is disodium EDTA (Trilon B). This paper presents the results of laboratory experiments for Trilon B-based solution development to remove scale under high-temperature conditions, as well as the results of corrosiveness reduction tests. Three various solutions were tested for corrosiveness. Minimal rate of corrosion for Trilon B-based solution was determined at 130°C. Quantitative and qualitative chemical analysis of scale composition was performed. Pilot tests of a new solution proved its high efficiency in scale removal from downhole pumping equipment. Laboratory and pilot tests showed that Trilon B-based solution is more efficient in removing inorganic scale from oilfield equipment during heavy oil production, compared to inhibited hydrochloric acid.
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Constituents > Salts/Sulphates/Scales (0.91)
Innovative solution for enhanced of oil recovery at shallow deposits of heavy oil (Russian)
Amerkhanov, M. I. (Tatneft PJSC, RF, Almetyevsk) | Zaripov, A. T. (TatNIPIneft, RF, Bugulma) | Beregovoy, Ant. N. (TatNIPIneft, RF, Bugulma) | Knyazeva, N. A. (TatNIPIneft, RF, Bugulma) | Belov, V. I. (TatNIPIneft, RF, Bugulma) | Razumov, A. R. (TatNIPIneft, RF, Bugulma)
The PDF file of this paper is in Russian. Tatneft came up with its heavy oil production program in 2005. In 2006, the pilot project was launched at Ashalchinskoye heavy oil field from drilling of three pairs of dual-wellhead wells with horizontal sections of the length 200–400 m. The first success promoted drilling of conventional single-wellhead horizontal well pairs with steam-assisted gravity drainage becoming the primary production method. In 2012, the project has gained a new momentum after the Russian Government introduced its tax incentives on production of heavy oil with in-situ viscosity of as high as 10,000 mPa⋅s. From then on, large-scale commercial production of shallow heavy oil has got underway in the Republic of Tatarstan. Over the course of project evolution, the Company's specialists has met various challenges, starting from selection of the optimal field development system and best strategies for drilling paired horizontal wells with optimal trajectories, selection of downhole equipment and advantageous pump operational characteristics and ending with field treatment and transport of produced oil with development of surface facilities construction projects. To date, the majority of complex challenges have been successfully addressed. This resulted in the increase of daily heavy oil production in Tatneft from several dozens of tones at the beginning of pilot production to more than 5 thousand tones. As of March 2018, cumulative heavy oil production has exceeded 3.8 million tons. One of the successful examples of innovative solutions is a novel, field proven technology which involves temporary shut-off the unwanted water production in paired horizontal production wells that penetrated water-producing intervals.
- Asia (0.55)
- Europe > Russia > Volga Federal District > Republic of Tatarstan (0.54)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > Europe Government > Russia Government (0.45)
- Government > Regional Government > Asia Government > Russia Government (0.45)
- Europe > Russia > Volga Federal District > Tatarstan > Volga Urals Basin > Ashalchinskoye Field > Ufa Formation (0.99)
- Europe > Russia > Volga Federal District > Tatarstan > Volga Urals Basin > Ashalchinskoye Field > Sheshminskiy Formation (0.99)
Analysis of causes for scaling on downhole pumping equipment in Ashalchinskoye heavy oil field (Russian)
Ibragimov, N. G. (Tatneft PJSC, RF, Almetyevsk) | Amerkhanov, M. I. (Tatneft PJSC, RF, Almetyevsk) | Beregovoy, Ant. N. (TatNIPIneft, RF, Bugulma) | Rakhimova, Sh. G. (TatNIPIneft, RF, Bugulma) | Ziatdinova, R. Sh. (TatNIPIneft, RF, Bugulma) | Khanipova, Yu. V. (TatNIPIneft, RF, Bugulma)
The PDF file of this paper is in Russian. In this work the authors have focused on analysis of causes for scale formation on pumps and downhole equipment in wells producing heavy oil. Thirty-three scale samples recovered from wells with downhole pumps failures have been analyzed. Various factors can contribute to emergency situations: carbonate salts may precipitate because of high mineralization of produced formation water and high temperature at the inlet of downhole pumps, or because of clogging of pump parts with formation particles, or solids. So, the problem must be addressed differently in each case. The first step is to determine why certain scale is formed on downhole equipment of SAGD-wells. To do this, pump inlet must provide for temperature sensors and solids sensors to detect solids content in produced water. Also, produced water quality must continuously be analyzed for physicochemical properties and composition. Then, parameters that characterize produced water saturation with carbonate salts are calculated. If these parameters are critical, salting inhibitors are injected into downhole equipment and bottomhole formation zone.If scale source is formation rocks, which is the case in unconsolidated rock, formation fines will enter the wellbore even at low differential pressure. In this case, gravel packs can be a useful tool to control scale formation. Also, this problem can be addressed by injecting polymer or hydrophobic systems into formation bottomhole zone, or at least, the well can be circulated with large volumes of aerated fluid. Of course, all these methods come at a cost; however, workover operations because of electric submersible pumps failure and the resultant well shutdown are translated eventually in much higher loss of profits.
World experience of solvents injection for extraction of heavy oil and solvent-based processes potential in TATNEFT PJSC heavy oil fields (Russian)
Yakubov, M. R. (A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center of RAS, RF, Kazan) | Amerkhanov, M. I. (Tatneft PJSC, RF, Almetyevsk) | Khisamov, R. S. (Tatneft PJSC, RF, Almetyevsk) | Khanipova, Yu. V. (TatNIPIneft, RF, Bugulma)
The PDF file of this paper is in Russian. Well-known technology of solvent-based recovery of heavy (extra-viscous) oils and bitumens has a number of indisputable advantages. They include the possibility of development of thin oil reservoirs, reduced or zero water consumption, significant decrease in the capital and operating expenditures, and reduction of the overall power consumption up to 85 %. The results of the current pilot projects show that this technology is competitive even in conditions of low oil prices. Physical simulation of the oil displacement process in conditions corresponding to the Ashalchinskoye field allows evaluating the applicability of composite solvents based on light aliphatic and aromatic hydrocarbons. It was established that application of the composite solvent based on the light saturate hydrocarbons only leads to deposition of the oil residues enriched with asphaltenes (up to 50–60 %) in the pore space. With the increase of proportion of aromatic hydrocarbon (toluene) in the composite solvent, precipitation of asphaltenes is decreased proportionally. Experimental simulation revealed the optimal concentration of aromatic hydrocarbon in the composite solvent based on pentane-hexane fraction for effective displacement of the extra-viscous oil. The velocity of the oil displacement and the volume of recoverable oil are both increased when the amount of asphaltenes deposited in the pore space is decreased. Various synthetic and natural amphiphilic substances behaving as inhibitors of asphaltene deposition process can be used in the composite solvent instead of toluene and other aromatic hydrocarbons.
- North America > Canada (0.29)
- Europe > Russia > Volga Federal District > Tatarstan (0.25)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Europe > Russia > Volga Federal District > Tatarstan > Volga Urals Basin > Ashalchinskoye Field > Ufa Formation (0.99)
- Europe > Russia > Volga Federal District > Tatarstan > Volga Urals Basin > Ashalchinskoye Field > Sheshminskiy Formation (0.99)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Oil sand, oil shale, bitumen (1.00)
- Reservoir Description and Dynamics > Improved and Enhanced Recovery (1.00)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Inhibition and remediation of hydrates, scale, paraffin / wax and asphaltene (1.00)
Intensification of thermal steam methods of production of heavy oil using a catalyst based on cobalt (Russian)
Sitnov, S. A. (Kazan (Volga Region) Federal University, RF, Kazan) | Petrovnina, M. S. (Kazan (Volga Region) Federal University, RF, Kazan) | Feoktistov, D. A. (Kazan (Volga Region) Federal University, RF, Kazan) | Isakov, D. R. (Kazan (Volga Region) Federal University, RF, Kazan) | Nurgaliev, D. K. (Kazan (Volga Region) Federal University, RF, Kazan) | Amerkhanov, M. I. (Tatneft PJSC, RF, Almetyevsk)
The pdf file of this paper is in Russian. The article aims to study the possibility of improving the efficiency of thermal steam methods of production of high-viscosity oil based on the results of laboratory modeling of catalytic and non-catalytic aquathermolysis. Study was conducted on the sample of high-viscosity oil of Ashalchinskoye field in conditions close to reservoir under thermal steam treatment: an initial pressure of 3 bar, temperature 150 and 180°C for 6 hours while adding the precursor (jointly and individually) of the catalyst and proton donor in the amount of 1% by weight of oil. Study presents the results of determining the viscosity-temperature characteristics and group composition by the SARA method of original and transformed oils. It is found that the oil samples after non-catalytic thermal steam exposure, both at 150°C and 180°C, are characterized by higher values of viscosity in comparison with other research subjects. It is connected, apparently, with the formation of high molecular weight alkanes as a result of the recombination of the destroyed fragments of high molecular weight components. In addition, the result of thermal steam exposure is a more dense structure due to the lack of protons available to bond with the formed radicals to prevent the process of increasing the molecular weight of the oil system. It is shown that the use of the catalyst, the active form of which is formed in situ, in combination with a protons donor allows to reduce the content of asphalt-resinous compounds. This provides an irreversible decrease in viscosity of produced oil, facilitates further transportation and processing.
- Europe > Russia > Volga Federal District > Tatarstan > Volga Urals Basin > Ashalchinskoye Field > Ufa Formation (0.99)
- Europe > Russia > Volga Federal District > Tatarstan > Volga Urals Basin > Ashalchinskoye Field > Sheshminskiy Formation (0.99)