CC BY
8EARTH SCIENCES
APPLICATION FEATURES OF SINGLE-LIFT UNITS FOR DUAL COMPLETION OF FACILITIES
OF MIDDLE AND LOWER CARBONIC STRATA
Semanov A.
Deputy Head of Geological and Hydrodynamic Modeling and Development Department No. 4
PJSC TATNEFT, Almetyevsk, Russia Semanova A. PJSC TATNEFT, Almetyevsk, Russia Fattakhov I.
Doctor of Technical Sciences, Associate Professor, Professor of Department of Exploration and Development of Oil and Gas Fields
Ufa State Petroleum Technical University (Oktyabrsky Branch), Oktyabrsky, Russia Head of the department for organization of enhanced oil recovery operations
PJSC TATNEFT, Almetyevsk, Russia https://doi.org/10.5281/zenodo.7032048
Abstract
More efficient technologies should be introduced when developing mature fields to maintain the profitability of oil production. This article considers a unit for dual completion of several facilities, which makes it possible to develop strata, the individual exploitation of which is unprofitable. The considered unit also makes it possible to develop multilayer facilities in a single grid. Today there are many different types of dual completion units, the application of which depends on geological and physical characteristics of the facility and technical characteristics of the well. By design, dual completion units can be divided to single-lift and dual-lift units. The advantage of the dual-lift scheme is the ability to obtain direct information on the flow rate, water cut of the strata being developed and the bottom hole pressure of the upper stratum. During the application of the single-lift scheme, there is no possibility to directly determine the performance of each facility. The need to use single-lift schemes for dual completion is determined by the fact that small-diameter well technologies are actively used today. In a number of cases, when connecting the productive stratum with the implementation of single-lift dual completion, it was not possible to achieve an increase in the flow rate. The performed studies showed that the predicted oil flow rate was not achieved due to the decrease in productivity of the upper horizon and lack of bottom hole pressure control in the lower facility, as well as a requirement for the presence of differential pressure between the facilities for the correct work of equipment. One of the solutions to this problem is the introduction of more advanced units for dual completion.
Keywords: oil production technologies, dual completion, bottom hole pressure, dual completion single-lift unit, unit with dividing piston.
Mature fields development should be carried out using more efficient technologies that provide an acceptable level of profitability. Well operation is often hampered by the problem of simultaneous fluid production from several productive horizons having different filtration-volume properties, as well as different characteristics of stratum oil and energetic states [1-2, 8, 19].
The technology of dual completion makes it possible to develop several facilities simultaneously without waiting for depletion of the lower strata. This production method allows to develop layers the separate exploitation of which is unprofitable. It also makes it possible to develop multilayer deposits as a single grid [3-5, 14, 16].
To date, there are a large number of different layouts of equipment for dual completion [11, 12, 15]. The choice of unit type depends on geological and physical properties of strata, technical arrangement and well condition. The peculiarities of unit design and choice of technological scheme are influenced by gas-oil ratio, stratum temperature and pressure, presence of mechanical impurities, composition of produced fluid, diameter of production string. According to the operating method, the technology can be divided into two types: simultaneous separate extraction of fluid from each of the separated facilities (dual completion) and simultaneous separate injection of the agent. Dual completion units can be divided into single-lift and dual-lift schemes (Figure 1).
Figure 1-Design scheme of layouts for dual completion: a) single-lift; b) dual-lift
The dual-lift configuration consists of a dual outfit, a packer to decouple the facilities, an anchor connecting the two lifts and two rod-depth pumps, with a rocker or chain drive used as the surface drive. Advantages of dual-lift scheme are the possibility to obtain direct measurements of fluid flow rate, watercut of connected facilities and pressure at the bottom hole of the upper facility.
The single-lift configuration (Figure 2), unlike the dual-lift configuration, includes only one bottom hole sucker-rod pump, the facilities are separated by a packer, and fluid enters the pump through the main and side suction (auxiliary) valves that are connected with
the stratum. The fluid from the area with lower bottom hole pressure enters through the main valve, while the fluid from the area with higher bottom hole pressure enters through the auxiliary valve.
In case of single-lift configuration, the production watercut and fluid flow rate cannot be determined directly [20]. However, it is possible to determine bottom hole pressure of the upper facility by the dynamic level. The load drop in the dynamogram (Figure 3) can be used to calculate the bottom hole pressure and the flow rate ratio. The plunger retooling can be used to leave one facility in operation, the top or the bottom one, depending on the location of the lateral suction valve.
Figure 2- Schematic diagram of a classic single-lift unit
Figure 3- Dynamogram of the dual completion single-lift system
To date, the technology of drilling small diameter wells is widely used. Most of them are drilled in multilayer fields [18]. In this regard, there is a necessity of using single-lift units for dual completion. Many wells currently use the classic dual completion single-lift units (Figure 2).
However, in a number of cases when connecting productive stratum with implementation of dual completion single-lift unit one could not reach the flow rate increment, in particular, when connecting Kizelovskiy horizon to Vereiskian one, oil flow rate increment was not obtained at several wells [6, 7, 9, 10].
The initial analysis showed that this problem is also relevant for other middle and lower carbonic strata. Compared were the average oil flow rates of wells by facility operating with single-lift dual completion and without dual completion. Figure 4 shows a graph comparing wells with and without dual completion and the number of wells involved in the calculation. The figure shows that the average flow rate of wells without dual completion is significantly higher than that of wells equipped with single-lift dual completion.
>. < C3
■a
S •» o
• -With dual completion -Without dual completion The number of wells
• • • • / * without dual completion • The number of wells with dual completion
• • Vv • •
• • •
• • • • • • • • •
• • • • • • • •
• • •
60
40
30
5
20
10
1 3 Î 7 9 11 13 1? 17 19 21 23
Month
Figure 4-
Dynamics of well performance equipped with and without single-lift dual completion, Vereiskian horizon
The performed studies (dynamic level measurements, installation of a pressure gauge, retooling of the plunger, analysis of the dynamogram history) showed that the decrease in productivity of the Vereiskian horizon was due to a drop in the dynamic level below the stratum top, which resulted in pore collapse, whereas gas release in the bottom-hole zone reduced the phase permeability of oil. The planned flow rate for the Kize-lovskiy horizon was not achieved since there was no bottom hole pressure control at the lower facility. The withdrawals from the facility decreased, dynamic level increased, but it was impossible to control these processes since the pressure measurements from the lower facility were not carried out. To control bottom hole pressure, it is necessary to lower a hydraulic smart controller into the well. At the same time, lowering of hy-
draulic smart controller for bottom hole pressure measurements in small diameter wells (dstnng=102 mm) is complicated.
A major problem is that the classic single-lift unit works only when there is a bottom hole pressure difference between the exploited facilities. Given the loss in production rate and the results of all the work done, it can be concluded that the dual completion technology between the middle and lower carbonic strata needs to be changed.
The following alternative units for dual completion can be used to solve this problem:
• Dual completion unit with dividing piston and product mixing. The scheme is shown in Figure 5a.
• Dual completion unit with dividing piston and additional lifting (dual completion AL). The scheme is shown in Figure 5b.
Figure 5 - Scheme of dual completion unit with dividing piston
a) With product mixing;
b) With separate lifting.
Figure 5 shows the dual completion unit with dividing piston. The advantage of this unit is that it works when there is no differential pressure between the facilities. The operating dynamogram of this unit can have a reverse step (Figure 6). Figure 5b shows a similar unit, but with separate lifting. As the string of rods moves upwards the fluid from the lower facility moves to the
extension and the lower part of the cylinder. Upon reaching the end of the lateral valve, the dividing piston stops and the fluid from the upper facility flows into the pump cylinder. When the plunger moves downward, the fluid of upper facility is displaced into hollow rods, the fluid from lower facility is displaced into tubing after the plunger reaches the dividing piston [13, 17].
Displacement of piston rod (mm)
Figure 6 - Operating dynamogram of the dual completion single-lift system with dividing piston
To evaluate the effectiveness of the dual completion unit with dividing piston, it was put into practice in 10 wells of middle or lower carbonic strata. The dual completion unit with a dividing piston has shown higher efficiency compared to the classic single-lift unit. This primarily can be explained by the fact that the
unit works effectively even without pressure differences between facilities.
One of the disadvantages of the dual completion unit with a dividing piston is that it can only be used in a production string with a diameter of 146 mm or more.
It is recommended to test this unit in simultaneous separate exploitation of middle and lower carbonic strata. However, in this case, the dual completion unit with dividing piston does not solve the problem of reducing the dynamic fluid level below the perforation interval. So, the following variants of exploitation of facilities of middle and lower carbonic strata are used:
• Operation of facilities by separate grid for maximum output;
• Operation of facilities as part of the existing technology with potential loss of production;
• Development of new technology to reduce production losses when working as part of dual completion.
References:
1. M. R. Arisar, M. Z. Hingoro, F. Abro, S. Na-wab, I. A. Hullio Optimizing the Production from a Multizone Well by Selecting Appropriate Completion for a Well of Tal Block Pakistan / Engineering, Technology & Applied Science Research Vol. 9, No. 3, 2019, 4108-4111 https://doi.org/10.48084/etasr.2677.
2. S. Hamid, Ricki Jannise, G. Garrison, M. Coffin New Technology Provides Zonal Pressure Maintenance in Single Trip Multizone Completions / SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, October 2017. Paper Number: SPE-187221-MS. https://doi.org/10.2118/187221-MS.
3. T. Grigsby, Ricki Jannise, A. Goodman, B. Techentien, Michael Schexnailder, Guy Navaira The Successful Development and Installation of a New Single-Trip Multizone Completion System Developed for the Deepwater Gulf of Mexico Lower Tertiary Formation / Paper presented at the Offshore Technology Conference, Houston, Texas, USA, May 2016. Paper Number: OTC-27222-MS. https://doi.org/10.4043/27222-MS
4. S. Jacob, Khalid M. Naimi Advanced Well Completion Designs to Meet Unique Reservoir and Production Requirements / Paper presented at the SPE Saudi Arabia Section Technical Symposium and Exhibition, Al-Khobar, Saudi Arabia, April 2014. Paper Number: SPE-172215-MS. https://doi.org/10.2118/172215-MS.
5. K. Muradov, E. Eltaher, D. Davies Reservoir simulator-friendly model of fluid-selective, downhole flow control completion performance / Journal of Petroleum Science and Engineering Volume 164, May 2018, Pages 140-154.
6. Babichev, I.N., Fattakhov, I.G., Kuleshova, L.S., Zaripov, L.F., Morozov, M.A. Potential for the wellbore zone development using the dynamic impact / IOP Conference Series: Earth and Environmental Science, 2019, 378(1), 012111.
7. Nurgaliev, R.Z., Kozikhin, R.A., Fattakhov, I.G., Kuleshova, L.S., Gabbasov, A.Kh. Prospects for the use of new technologies in assessing the impact of geological and technological risks / IOP Conference Series: Earth and Environmental Science, 2019, 378(1), 012117.
8. Nurgaliev, R.Z., Kozikhin, R.A., Fattakhov, I.G., Kuleshova, L.S. Application prospects for new technologies in geological and technological risk assessment / Gornyi Zhurnal, 2019, (4), p. 36-40.
9. Kozikhin, R.A., Daminov, A.M., Fattakhov, I.G., Kuleshova, L.S., Gabbasov, A.K. Identifying the efficiency factors on the basis of evaluation of acidizing of carbonate reservoirs / IOP Conference Series: Earth and Environmental Science, 2018, 194(6), 062013.
10. Bahtizin, R.N., Nurgaliev, R.Z., Fattakhov, I.G., Andreev, V.E., Safiullina, A.R. On the question of the efficiency analysis of the bottom-hole area stimulation method / International Journal of Mechanical Engineering and Technology, 2018, 9(6), p. 1035-1044.
11. Аминев, М.Х. Скважинное оборудование для ОРЭ: новые разработки, внедрение, сервис / М.Х. Аминев // Инженерная практика. - 2011. - № 3. - С. 28-35.
12. Гарифов, К.М. История и современное состояние техники и технологии ОРЭ пластов в ОАО «Татнефть» / К.М.Гарифов // Инженерная практика.
- 2010. - № 1. - С. 19-29.
13. Гарифов, К.М. Применение одновременно-раздельной эксплуатации пластов в ОАО "Татнефть" / К.М. Гарифов, А.В. Глуходед, Н.Г. Ибрагимов, В.Г. Фадеев, Р.Г. Заббаров // Нефтяное хозяйство. - 2010. - № 7. - С. 55-57.
14. Дияшев, Р.Н. Особенности разработки многопластовых объектов / Р.Н. Дияшев и др. - Экспресс-информ. ВНИИОЭНГ. Сер. «Нефтепромысловое дело»,1987. - 203 с.
15. Емельянов, А.В. Скважинные компоновки для одновременной добычи и обработки ПЗП / А.В. Емельянов // Инженерная практика. - 2011. - № 3.
- С. 58-62.
16. Мищенко, И.Т. Скважинная добыча нефти / И.Т. Мищенко. - М.: «Нефть и газ», 2003.- 816с.
17. Ибрагимов, Н.Г. Новые технические средства одновременно-раздельной эксплуатации, разработанные в ОАО "Татнефть" / Н.Г. Ибрагимов, В.Г. Фадеев, Р.Г. Заббаров, Р.Н. Ахметвалиев, К.М. Гарифов, А.Х. Кадыров // Нефтяное хозяйство. -2008. - № 7. - С. 79-81.
18. Хисамов, Р.С. Особенности геологического строения и разработки многопластовых нефтяных месторождений / Р.С. Хисамов. - Казань: изд-во «Мониторинг», 1996.- 288 с.
19. Егорова Ю.Л., Низаев Р.Х., Иванов А.Ф., Фаттахов И.Г. Использование геологического и гидродинамического моделирования для изучения пространственного ориентирования трещин в карбонатных коллекторах на основе трассерных методов исследования / Нефтяная провинция. № 1(17) 2019, стр. 116-125.
20. Фаттахов И.Г., Кулешова Л.С., Якубова Д.И., Мурдашева Л.В., Гафаров Р.Р., Шайдуллин Р.Р. Оценка эффективности водоизоляции на основе модельных исследований / Материалы 45-й научно-технической конференции молодых ученых, аспирантов и студентов. - Уфа: Изд-во УГНТУ, 2018. - С. 180-182.
