Non-stationary Waterflooding Research Articles

Updating a reservoir geological model in order to optimize waterflooding when extracting residual oil reserves from stagnant zones

Background. In the Russian Federation, as well as in many other oil and gas producing countries, waterflooding technology is frequently used as a secondary method of oil production. This technology is aimed, on the one hand, at reservoir pressure maintenance (RPM), and, on the other, at enhancing oil recovery and intensifying oil production. The negative consequences of non-stationary waterflooding can be the premature watering of the produced wells and the imbalance of the reservoir pressure maintenance system, as well as the formation of stagnant and weakly drained zones of the reservoir with residual reserves of hard-to-recover oil.Aim. To improve the efficiency of non-stationary waterflooding under the conditions of high geological and anthropogenic heterogeneity of oil and gas reservoirs in a floating oil reservoir propped up by edge and bottom waters.Materials and methods. We used geological and field information collected on the site of the AB1-2 development object of the Kechimovskoye field in the Western Siberian region. A new methodological approach to optimizing the process of non-stationary waterflooding under complicated conditions of geological and anthropogenic heterogeneity is proposed, including the construction of an improved geological model and the solution of a number of experimental problems using the Hurst method, the Pareto distribution principle and the theory of catastrophes.Results. Using a new version of the geological model of the area of the AB1-2 development object of the Kechimovskoye field and the available geological and field information, we clarified the position of the oil-water contact (OWC) and the correlation of the well section, taking into account the working intervals of production and injection wells. Geological and technical measures were formulated to improve the efficiency of the object under development.Conclusions. An effective development of the geologically complex AB1-2object of the Kechimovskoye field is impossible without updating its geological model. Such updating should be aimed at determining the location of residual reserves in the area and section of the reservoirs, identifying the regularities of the mechanism of oil reserve recovery, assessing the efficiency of the reservoir pressure maintenance system, and developing complex geological-technological measures for achieving the approved value of the final oil recovery factor. The expected efficiency of the proposed optimization methodology provides for additional oil production, a reduction in the flow rate of injected and withdrawal of produced water.

Development of devices for implementation pulse nonstationary waterflooding

To further improve the efficiency of the non-stationary flooding (acceleration of capillary impregnation oil closed pores) at the bottom of injection wells installed devices, creating pulses in the pumped liquid, with a packer. The article deals with a device designed for this purpose. A mathematical model of the device and output expressions to define the basic operating parameters of output. For comparison of theoretical calculations show the results of bench testing device. In view of previous research, the authors of substantiated the effectiveness of such devices for the nonstationary flooding in the system to maintain reservoir pressure. The preliminary positive data on fishing the use of these devices in the fields of NC «Rosneft» in 2015-2016.

Development of the non-stationary waterflooding technology

The article analyzes the non-stationary waterflooding technology. The basic physical principles of the technology are described. The reasons for its low popularity among subsoil users are revealed. The article aims to substantiate the relevance of non-stationary technologies, conduct experimental-industrial works to adapt and create new non-stationary technologies, and determine conditions for their effective application. In the 1990s, Western technologies were widely used in the oil industry. Non-stationary waterflooding was not included in the list of these technologies. Despite its relative simplicity, the practical implementation of the non-stationary waterflooding technology requires preparation works. Non-stationary waterflooding is one of the most knowledge-intensive methods of enhanced oil recovery. Non-stationary waterflooding tends to “age”, i.e. its effectiveness decreases over time, which requires constant changes in the technology and its combination with other methods.

Forecasting the use of non-stationary waterflooding in the conditions of oil deposits in Western Siberia

The researchers have developed simplified models of the studied formations in the Langepasneftegaz TPP to forecast the effectiveness of using non-stationary waterflooding with flow control and flow diverting technologies. To increase oil recovery and intensify the influx of oil from the reservoirs, they recommended the integration of technologies. The article shows that complex technologies for impacting oil and gas deposits using non-stationary waterflooding aimed at increasing the oil recovery coefficient and limiting the movement of water in the reservoir while stimulating the bottom-hole zones of the reservoir will significantly increase the efficiency of field development.

ПРИМЕНЕНИЕ ИНСТРУМЕНТОВ DATA MINING ПРИ ПЛАНИРОВАНИИ НЕСТАЦИОНАРНОГО ЗАВОДНЕНИЯ

ПРИМЕНЕНИЕ ИНСТРУМЕНТОВ DATA MINING ПРИ ПЛАНИРОВАНИИ НЕСТАЦИОНАРНОГО ЗАВОДНЕНИЯ

Changes in formation pressure and technological efficiency of unsteady flooding in double permeability reservoirs having different productivity rates

Unsteady waterflooding went through several stages. Within the pilot works in April 2009, cyclical water injection was started in Block 7 (central section). In addition, alternate water injection into the horizons of the Jurassic and Cretaceous sediments of Block 10 began. For this purpose, injection wells equipped with devices for simultaneous separate water pumping were used. The significant effect of non-stationary waterflooding in the experimental sections allowed for the application of the technology in other blocks. The technology implementation scheme was applied for injection wells of Blocks 6 and 10. Since July 2010, cyclic injection has been used for many wells. Periods of non-stationary operation of injection wells were determined experimentally. The reservoirs with heterogenous permeability containing highly permeable and low-permeable layers are the most optimal ones. The heterogenous structure of the reservoir provides a large contact area between layers with different permeability levels which allows for non-stationary effects due to the occurrence of overflows between the layers. It can reduce the water content of the products and increase oil production.

Application of the non-stationary waterflooding technology and periodical operation of production wells for heterogeneously permeable reservoirs

Application of the non-stationary waterflooding technology at the Kumkol field (the Republic of Kazakhstan) had a number of unsolved problems. The main problem is correct selection of parameters for the non-vascular flooding technology - an amplitude and a cycling impact frequency. The amplitude of impact is determined by the capabilities of the reservoir pressure maintenance system (RPM) and the ability of the reservoir to absorb large volumes of water. The impact frequency is a more unstable parameter depending on the structure of the reservoir and saturation of heterogeneous fluids. For the Kumkol field conditions, the void reservoir space has a complex multi-level structure. There are pore reservoirs with different permeability rates, highly permeable layers located over the deposits, filtration channels with very high permeability (cracks, a super collector). In addition, there are three phases of reservoir fluids (oil, water, free gas). All this creates uncertainty in setting frequency parameters of the non-stationary waterflooding method. The article deals with the issue of determining frequencies of impact.

To the issue of optimizing the application of the sealing equipment in the injection well at the long-term pulsed water injection into it

When determining the operability of the sealing elements, it is necessary to take into account the overall movement of the packer during operation, which it passes before the damage of the sealing elements when fixing the leakage failure in the annulus. It should be noted that as the frequency and the amplitude of the pressure of injected liquid pulses increase, the distance travelled increases proportionately. According to preliminary calculations, the average leakage volumes of injected fluids are in the range 0,005 ... 0,1 cm3/m2with the prevalence of possible leakages at the level of 0,05 cm3/m2. As a result of preliminary calculations, it was found that the average performance of mechanical packers in the case of nonstationary waterflooding impulse before identifying significant leaks was 30,000...50,000 km. It should be taken into account that with increasing frequency and amplitude of the pressure of pulses in the injected fluid, the operability and longevity of the packer seal reduce. The article suggests recommendations for improving the reliability of packers for long-term pulsed water injection into injection wells.

Прогнозирование надежности колонны насосно-компрессорных труб при импульсном нестационарном заводнении

Прогнозирование надежности колонны насосно-компрессорных труб при импульсном нестационарном заводнении

Modelling and assessing the effectiveness of developing the Shumovskoye field

With the depletion of light oil stock, the heavy high-viscosity oil stock is rising. In this regard, there appear the technologies allowing to provide industrial levels of high-viscosity oil extraction. Therefore, the research of effective methods of developing heavy high-viscosity oil pools is one of the important development directions in the oil industry. One of the most cost-effective technology is non-stationary waterflooding (NW). There are currently not so many examples of using the technology of non-stationary waterflooding at the HVO pools. This is due to the fact that waterflooding as a development method has low efficiency at the HVO pools. The obtained results, based on modelling, showed that the technology of non-stationary impact is quite effective.

Recommendations on thermal non-stationary waterflooding when modeling oil field development

The work shows the efficiency of non-stationary waterflooding at first and second exploitation zones under contemporary conditions of Severnye Buzachi oil field. Moreover, at the sites with cyclic treatment, the volume of non-stationary waterflooding significantly decreased due to implementation of the technology of thermal treatment. The problem is the choice of a most preferable oil production method in terms of technological and economical conditions of high-VI oil reservoir development. However, the most important issue is the study of the possibility to combine two said technologies with joint benefit from their strong points for the sake of maximum oil displacement efficacy.

Forecasting the parameters of non-stationary water flooding of oil deposits

Non-stationary flooding and water withdrawal with changing the direction of filtration flow as a secondary advanced recovery method allow enhancing oil deposit coverage by filtration processes, reducing or eliminating the amount of bypassed oil in productive formations. Process modelling should be provided for correct forecast about the efficiency of non-stationary formation stimulation. A formation model was designed for modelling cyclic water flooding. There are cross-flows between interlayers of reservoir robbing which have different porosity and permeability properties and unbalanced thrust in pore space. It is noted that when applying ordinary water flooding, high formation heterogeneity, higher than average oil viscosity and low permeability make it impossible to reach even average efficiency of oil pool development. The choice of a stimulation technique and its justification is an important step of planning in order to apply non-stationary stimulation. A possibility to apply non-stationary flooding efficiently for the analysed object has been established.

Complex research of the application of the non-stationary waterflooding in interrelationship with other EOR methods

The article is concerned with the application of non-stationary waterflooding (NW) on the example of «LUKOIL-Western Siberia» fields. The experience of selection of candidate wells for NW has been analyzed, and the criteria for selecting an area for the application of the method have been developed, taking into account the conduct of other oil recovery enhancement operations (EOR) in the near regions. Recommendations are given on the use of NW in conjunction with other methods of EOR.

HISTORY OF NON-STATIONARY WATER FLOODING TECHNOLOGY DEVELOPMENT AT KUMKOL OIL FIELD

In the article introduction and development stages of non-stationary waterflooding technol-ogy are considered at Kumkol oil field example. It is shown that the history of non-stationary waterflooding application at Kumkol oil field allows to determine the main trends of technology development. The application of non-stationary waterflooding begins as pilot-industrial work on a designated site. In this case, most often begin with the application of cyclics, i.e. all injection wells simultaneous discon-nection/activation of the site during the half cycle period. The analysis of the results of pilot-industrial works makes it possible to decide on the extension of the sections or on the application of non-stationary waterflooding on the entire site (oil field). In this case, the experience of managing the operation of injection wells in a batch mode without complica-tions in the reservoir pressure maintenance system is analyzed. During the time passing, the efficiency of the cyclic water injection technology starts decreas-ing, that needs using new types of non-stationary waterflooding. At the Kumkol oil field, the cyclic mode was replaced by non-stationary waterflooding + change in the direction of the filtration flow due to the selection of injection wells groups, each of which operates in its mode. However, this technology also begins «aging» with time and efficiency reduces. Further development of non-stationary waterflooding is associated with a combination of cyclic water injection and high-water-producing wells periodic operation. This direction of non-stationary waterflooding has great flexibility and can be constantly modified.

IMPROVED SEWAGE TREATMENT SYSTEM AT THE PULSED NON-STATIONARY WATERFLOODING

Background In order to maintain reservoir pressure for injection into the wells, it is preferable to use wastewater that is produced together with the hydrocarbon liquid. After separating it from oil in integrated oil treatment plants, it becomes necessary to clean it before injection into the reservoir. Aims and Objectives Based on the analysis of existing wastewater treatment systems before their injection into wells, develop an improved application scheme that does not require significant material investments for its implementation. Results The application of the sewage treatment system will reduce the occupied areas of the purification system by combining them into one, improve the quality of treatment, obtain additional sources of recycled water for technical use and provide the required volume of water for pulsed non-stationary water flooding.

Исследование процессов стационарного и нестационарного заводнения трещиновато-пористых коллекторов

Исследование процессов стационарного и нестационарного заводнения трещиновато-пористых коллекторов

Расширение опыта применения технологии нестационарного заводнения с применением технологии изменения направления фильтрационного потока на примере месторождения Северные Бузачи

Расширение опыта применения технологии нестационарного заводнения с применением технологии изменения направления фильтрационного потока на примере месторождения Северные Бузачи