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7Бурение скважин и разработка месторождений
Drilling of wells and fields development
2.8.4. Разработка и эксплуатация нефтяных и газовых месторождений
(технические науки)
УДК 622.243(571.12)= 111 DOI: 10.31660/0445-0108-2022-2-53-60 Comprehensive justification of the Tyumen suite development system
Dmitrii S. Berdnikov*, Anastasiia S. Zakharova, Anastasiia E. Sorokina
Tyumen Petroleum Scientific Center LLC, Tyumen, Russia *dsberdnikov@tnnc.rosneft.ru
Abstract. The article objectives are developing hard-to-recover reservoirs and how to maximize oil production by formulating effective solutions for putting hard-to-recover reserves.
US2 is planned to be put into development in 2022 and contains 52% of the initial reserves of the entire field. US2 reservoir complicated by low permeability 0.6 mD, saturated intervals are 9.8 m.
The main method of developing hard-to-recover reserves in Western Siberia fields is horizontal drilling with multi-stage hydraulic fracturing. As a matter of course, well designs were analyzed with different lengths of horizontal shaft and with a different number of hydraulic fracturing ports. Calculations of starting flow rates and production profiles for various well options for a typical well have been performed. The optimal solution was evaluated using the complex parameter NPV and cumulative production.
Keywords: hard-to-recover reservoirs, efficient development, drilling, methodology, low-permeability reservoirs
For citation: Berdnikov, D. S., Zakharova, A. S., & Sorokina, A. E. (2022). Comprehensive justification of the tyumen suite development system. Oil and Gas Studies, (2), pp. 53-60. (In Russian). DOI: 10.31660/0445-0108-2022-2-53-60
Комплексное обоснование системы разработки тюменской свиты Д. С. Бердников*, А. С. Захарова, А. Е. Сорокина
ООО «Тюменский нефтяной научный центр», Тюмень, Россия *dsberdnikov@tnnc.rosneft.ru
Аннотация. Целью статьи является максимизация добычи нефти путем формирования эффективных решений по вводу в разработку трудноизвлекаемых запасов месторождения Т.
Основную часть трудноизвлекаемых запасов (52 %) занимает пласт ЮС2, ввод которого в разработку запланирован на 2022 год. ЮС2 характеризуется низкой проницаемостью 0,6 мД, нефтенасыщенная толщина составляет 9,8 м.
Основным методом разработки трудноизвлекаемых запасов месторождений Западной Сибири является горизонтальное бурение с многостадийным гидроразрывом пласта. В статье проводится анализ конструкций скважин с разной длиной горизонтального ствола и с разным количеством портов ГРП. Выполнены расчеты стартовых дебитов и профилей добычи для различных вариантов скважин для типовой скважины. Оценка оптимального решения проводилась с использованием комплексного критерия NPV и накопленной добычи.
Ключевые слова: трудноизвлекаемые запасы, эффективная разработка, бурение, методика, низкопроницаемый коллектор
Для цитирования: Бердников, Д. С. Комплексное обоснование системы разработки тюменской свиты / Д. С. Бердников, А. С. Захарова, А. Е. Сорокина. - DOI 10.31660/0445-01082022-2-53-60 // Известия высших учебных заведений. Нефть и газ. - 2022. - № 2. - С. 53-60.
Introduction
Currently, the issue of developing hard-to-recover reservoirs is becoming more and more topical. A few of recoverable oil reservoirs in Russia (over 65%) are relating to low-permeability reservoirs. Therefore, the efficient development of hard-to-recover reserves is one of the most important objects of oil and gas companies. The Tyumen suite has great potential, but traditional methods are ineffective for the development of such complicated reservoirs [1, 2].
The article objective is to maximize oil production by formulating effective solutions for putting hard-to-recover reservoirs into development using the example of the US2 reservoir of the T. field.
Object and research methods
The T. field is located in the Tyumen region, on the border of the Khanty-Mansiysk and Surgut regions. The commercial oil and gas content of the field is confined to oil reservoirs: ASb AS4, AS6-2, US0, US2, US4 and USi0. The layers of the Tyumen suite (US2, US4 and US10) are characterized by low permeability values and classified as hard-to-recover reservoirs [3]. These formations contain over 60% of the initial reserves of the entire field. The main part of hard-to-recover reservoirs (52%) is occupied by the US2 layer of the T. field, which is planned to be put into development in 2022 (Tab. 1).
Table 1
Hard-to-recover reservoirs properties
Hard-to-recover reserves (Kd = 0.2) US2 US4 US10
Permeability, mD < 2 ✓ 0.6 ✓ 0.2 ✓ 1.7
Saturated intervals, m < 10 ✓ 9.8 ✓ 5.9 ✓ 9.8
The current design solution is an in-line system with a well spacing 800 m. All wells are horizontal with multistage hydraulic fracturing, horizontal wells with a length of 800 m, at each 4th stage of hydraulic fracturing.
Effectiveness of the existing design solutions of the reservoir US2 was assessed. During the pilot period, 3 wells were drilled (including 2 horizontal wells with a length of 500 m, 5 hydraulic fracturing stages). According at a rough guess of decline rates in oil flowrate, there is a significant excess relative to the design ones (plan -22 %, actual -70 %) (Fig.1). The sharp deviation of the predicted rates from the actual ones is due to the lack of response to injection at the current well spacing.
с «Г
4—I
О с
a>
4-»
<v с
<y
и
1 0.8 0.6 0.4 0.2 0
0.78
0.3
*PTD
Fact
2 3 4 5 6 7 8 9 10 11 12 Month
Fig. 1. Decline rates in oil flowrates
In addition, based on the results of drilling and pilot testing, the geological concept was refined - the permeability increased by 15% and became 0.6 mD.
Taking into account the high rates of decline, a methodology has been prepared to substantiate the optimal system for the development of objects complicated by low permeability (Fig. 2). The main method of developing hard-to-recover reservoirs in Western Siberia fields is horizontal drilling with multistage hydraulic fracturing [2, 4-6].
Fig. 2. Methodology for substantiating the development system
As a matter of course, well designs were analyzed with different lengths of horizontal shaft and with a different number of hydraulic fracturing
ports [7-9]. Calculations of starting flow rates and production profiles for various well options for a typical well have been performed. The optimal solution was evaluated using the complex parameter NPV and cumulative production.
Results and discussion
Based on the results of the analysis of well indicators for similar fields, it is recommended to take the direction of the designed horizontal wells in the azimuth of 165°-345° (along the stress) [10-13]. Based on the results of calculations, for Lgs 800-1300 m, the optimal distance between hydraulic fracturing ports is 90-120 m, and for Lgs 1300-1700 m, the optimal distance between hydraulic fracturing ports is 130-160 m (Fig. 3).
Fig. 3. Determination of the optimal number of hydraulic fracturing ports
Using the complex parameter (1), which takes into account NPV and cumulative production for options with different number of hydraulic fractures and length of horizontal wells, the optimal length of horizontal wells for the US2 formation was determined as 1500 m [14-15].
K = V ^npv * KQ >
(1)
NPV - NPV* Q-Q*
where KNPV =-——-, K0 = —--.
NPV* Q Q*
To determine the ratio of production and injection wells in the US2 formation the following equation was used (2):
(P -PProd\MProd2 KGW = (rres rbh J" ^oil^prod ~
K™dif Dw\ . (2)
For the directional well maintain reservoir pressure system, the ratio of production to injection pressure is 1 : 3, for horizontal wells maintain reservoir pressure system, the ratio is 1 : 1 [16-18].
Using a complex parameter, the optimal time for the injection wells flow-back was determined (Fig. 4), which is 3 months.
Ô о.?
Without flow 3 months 6 months 12 months
back
0.1
0.0 — Without maintain formation pressure
Fig. 4. Determination of the optimal time of injection wells development
To determine the well network, a full-size hydrodynamic model was used, as well as a complex parameter. According to the calculation results, the optimal option is with a grid density of 87 hectares/well and the distance between the rows is 400 m. According to the results of the calculation, the rates of decline are characterized by more optimistic dynamics in comparison with the actual ones (Fig. 5).
1Л
E
V»
f 02 W
<li — PTD -Fact ^—Recommended
.E o
u 1 2345 6789 10 11 12
o
Month
Fig. 5. Decline rates in oil flowrates
Three options were involved in the comparison: "project-technological document" - technological indicators of the current PTD without taking into account the revised geology, "Basic" - solutions of the current project document
applied in an updated geological view, "Recommended" - proposed design solutions based on the results of justification. A detailed description of the options is presented in table 2.
The economic evaluation of the three options showed that the recommended option with a horizontal well length of 1500 m, a distance between hydraulic fracturing ports of 150 m and a grid spacing of 400 m is characterized by the best economic indicators (Fig. 6).
Table 2
Comparison of options
Parameter PTD Basic Recommended
Production well completion type Horizontal well with multifrac
Injection well completion type
Horizontal well length, m 800 800 1500
Distance between hydraulic fracturing ports, m 200 200 150
Distance between the rows, m 800 800 400
Well stock, units 90 103 165
Cumulative oil production (40 years), million tons 11.9 11.2 15.7
NPV, units - 1 1.7
о Ъ
z
TJ
о _
a.
5
1200 1000 soo 600 400 200 0
I
ill IL llli.
11
16
2'
Year
26
3'
36
41
100
SO
60 -Ё
40 J i
20 8 0 5
Well commissioning, basic Well commissioning, PTD Oil production, recommended
Well commissioning, recommended Oil production, basic Oil production, PTD
Fig. 6. Comparison of starting metric options
The application of the recommended design solutions will increase the cumulative oil production relative to the base case by 103%, NPV - by 70%.
Conclusion
In reservoirs with low permeability the main method of developing is horizontal drilling with multi-stage hydraulic fracturing [19-20]. In the course of work well designs with different lengths of horizontal shaft and with a different number of hydraulic fracturing ports were determined by complex parameter.
The formulated approaches to substantiating the development system can be replicated in the fields of Western Siberia, the oil-bearing capacity of which is confined to the Tyumen suite.
References
1. Aliev Z. S., Somov B. E., & Chekushin, V. F. (2001). Justification of the design of horizontal and multilateral horizontal wells for the development of oil fields. Moscow, Tekhnika Publishing House, Tuma group LLC, 192 p. (In Russian).
2. Baluev, A. A., Vityaz, A. V., & Semenenko, A. F. (2019). Selection of the optimal design of the production bottomhole of wells in complex fields of Western Siberia with hard-to-recover reserves. Proceedings of the All-Russian Scientific and Technical Conference dedicated to the 45th anniversary of the Tyumen fuel and energy complex and the 80th anniversary of V. I. Greyfer. Tyumen, 143 p. (In Russian).
3. Belonogov, E. V., Pustovskikh, A. A., Samolovov, D. A., Sitnikov, A. N. (2016). Determination of criteria for choosing the optimal development method in low-permeability reservoirs. SPE-180241-RU. (In English).
4. Fokeeva, L. Kh. (2006). Determination of the optimal trajectory and lengths of multilateral horizontal wells taking into account the characteristics of the reservoir. Oil and Gas Business, (2). (In Russian). Available at: http://ogbus.ru/files/ogbus/authors/Fokeeva/Fokeeva_1.pdf
5. Mukherjee, H., & Economides, M. J. (1988). A Parametric Comparison of Horizontal and Vertical Well Performance. SPE paper 18303. 63rd Annual Technical Conference, Houston, TX, October, 2-5, 1988. (In English).
6. Conlin, J. M., Hale, J. L., Sabathier, J. C., Faure, F. & Mas, D. (1990). Multiple-Fracture Horizontal Wells: Performance and Numerical Simulation. SPE paper 20960. Europec 90, The Hague, Netherlands, October, 22-24, 1990. (In English).
7. Merkulov, V. P. (1958). Le debit des puits devise et horizontaux. Neft. Khoz, 6, pp. 51-56. (In Russian).
8. Giger, F. M., Reiss, L. H., & Jourdan, A. P. (1984). The Reservoir Engineering Aspects of Horizontal Drilling. SPE paper 13024. Annual Technical Conference, Houston, Texas, September, 16-19, 1984. (In English).
9. Giger, F. M. (1985). Horizontal Wells Production Techniques in Heterogeneous Reservoirs. SPE paper 13710. SPE Middle East Oil Technical Conference, Bahrain, March, 11-14,
1985. (In English).
10. Karcher, B. J., Giger, F. M., & Combe, J. (1986). Some Practical Formulas to Predict Horizontal Well Behavior. SPE paper 15430. 61st Annual Technical Conference, New Orleans, LA, October, 5-8, 1986. (In English).
11. Joshi, S. D. (1986). Augmentation of Well Productivity Using Slant and Horizontal Wells. SPE paper 15375. 61st Annual Technical Conference, New Orleans, LA, October, 5-8,
1986. (In English).
12. Babu, D. K., & Odeh, A. S. (1988). Productivity of a Horizontal Well. SPE paper 18298. 63rd Annual Technical Conference, Houston, Texas, October 2-5, 1988. (In English).
13. Kuchuk, F. J., & Goode, P. A. (1988). Pressure Transient Analysis and Inflow Performance for Horizontal Wells. SPE paper 18300. 63rd Annual Technical Conference, Houston, Texas, October, 2-5, 1988. (In English).
