Efficiency of reservoir pressure maintenance system in low-permeable heterogeneous reservoirs

2021 ◽  
pp. 63-78
Author(s):  
Yu. A. Plitkina

The article presents a generalization of experience in organizing the reservoir pressure maintenance system in low-permeability reservoirs of Tyumen suite. The author of the article considers the issues of influence of the density of the grid of directional wells and the intensity of waterflooding on the efficiency of the reservoir pressure maintenance system. The question of the need to take into account the orientation of the horizontal wells with multistage hydraulic fracturing system with respect to regional stress in order to minimize the breakthrough of the injected water is disclosed in detail. A comparative characteristic of the efficiency of the reservoir pressure maintenance in the system "along" and "across" of stress is given. A new express method is described for determining the optimal oil production period individually for each injection well, which allows maximizing oil production without additional costs. The author of the article gives recommendations for monitoring and regulating water injection.

2019 ◽  
pp. 81-85
Author(s):  
Damir K. Sagitov

The study of the causes of changes in the effectiveness of the reservoir pressure maintenance system in terms of the interaction of injection and production wells is an important and insufficiently studied problem, especially in terms of the causes of the attenuation of stable connections between the interacting wells. Based on the results of the calculation of the Spearman pair correlation coefficient, the reasons for the change in the interaction of wells during the flooding process at various stages were estimated. Of particular interest are identified four characteristic interactions, which are determined by the periods of formation of the displacement front.


Author(s):  
Sudad H AL-Obaidi ◽  
Miel Hofmann ◽  
Falah H. Khalaf ◽  
Hiba H. Alwan

The efficiency of gas injection for developing terrigenous deposits within a multilayer producing object is investigated in this article. According to the results of measurements of the 3D hydrodynamic compositional model, an assessment of the oil recovery factor was made. In the studied conditions, re-injection of the associated gas was found to be the most technologically efficient working agent. The factors contributing to the inefficacy of traditional methods of stimulating oil production such as multistage hydraulic fracturing when used to develop low-permeability reservoirs have been analyzed. The factors contributing to the inefficiency of traditional oil-production stimulation methods, such as multistage hydraulic fracturing, have been analysed when they are applied to low-permeability reservoirs. The use of a gas of various compositions is found to be more effective as a working agent for reservoirs with permeability less than 0.005 µm2. Ultimately, the selection of an agent for injection into the reservoir should be driven by the criteria that allow assessing the applicability of the method under specific geological and physical conditions. In multilayer production objects, gas injection efficiency is influenced by a number of factors, in addition to displacement, including the ratio of gas volumes, the degree to which pressure is maintained in each reservoir, as well as how the well is operated. With the increase in production rate from 60 to 90 m3 / day during the re-injection of produced hydrocarbon gas, this study found that the oil recovery factor increased from 0.190 to 0.229. The further increase in flow rate to 150 m3 / day, however, led to a faster gas breakthrough, a decrease in the amount of oil produced, and a decrease in the oil recovery factor to 0.19 Based on the results of the research, methods for stimulating the formation of low-permeability reservoirs were ranked based on their efficacy.


2021 ◽  
Author(s):  
Nadir Husein ◽  
Evgeny Aleksandrovich Malyavko ◽  
Ruslan Rashidovich Gazizov ◽  
Anton Vitalyevich Buyanov ◽  
Aleksey Aleksandrovich Romanov ◽  
...  

Abstract Today, efficient field development cannot be managed without proper surveillance providing oil companies with important geological and engineering information for prompt decision-making. Once continuous production is achieved, it is necessary to maintain a consistently high level of oil recovery. As a rule, a reservoir pressure maintenance system is extensively implemented for this purpose over the entire area because of decreasing reservoir pressure. At the same time, it is important to adjust the water injection to timely prevent water cut increasing in production wells, while maintaining efficient reservoir pressure compensation across the field. That is why it is necessary to have a relevant inter-well hydrodynamic model as well as to quantify the water injection rate. There are many ways to analyse the efficiency of the reservoir pressure maintenance system, but not all of them yield a positive, and most importantly, a reliable result. It is crucial that extensive zonal production surveillance efforts generate a significant economic effect and the information obtained helps boost oil production. Thus, the main objective of this paper is to identify a method and conduct an effective study to establish the degree of reservoir connectivity and quantify the inter-well parameters of a low permeability tested field.


2021 ◽  
Vol 1201 (1) ◽  
pp. 012084
Author(s):  
I M Kurchatov

Abstract Failures of reservoir pressure maintenance system at offshore facilities cause production losses and a significant increase in OPEX. Predicting failures of a water injection pump or its parts can highly improve the overall performance by promptly adjusting operating parameters to prevent failure occurrence or by scheduling maintenance to reduce unplanned repairs and to minimize downtime. This is particularly relevant for Arctic offshore projects, characterized by considerable logistical challenges and substantial environmental safety risks. The paper presents a data-analytic approach for failure prediction for the water injection pump operated at the ice-resistant GBS Prirazlomnaya. The study used pump failure history and field sensor data to predict the technical condition and identify a failed component in advance. An ARIMA model implemented in the R software environment was developed for the analysis. The results demonstrate that the approach works appropriately based on the generalized risk assessment and feedback from subject matter experts.


2020 ◽  
Vol 21 (1) ◽  
pp. 39-44
Author(s):  
Ayat Ahmed Jassim ◽  
Abdul Aali Al-dabaj ◽  
Aqeel S. AL-Adili

The water injection of the most important technologies to increase oil production from petroleum reservoirs. In this research, we developed a model for oil tank using the software RUBIS for reservoir simulation. This model was used to make comparison in the production of oil and the reservoir pressure for two case studies where the water was not injected in the first case study but adding new vertical wells while, later, it was injected in the second case study. It represents the results of this work that if the water is not injected, the reservoir model that has been upgraded can produce only 2.9% of the original oil in the tank. This case study also represents a drop in reservoir pressure, which was not enough to support oil production. Thus, the implementation of water injection in the second case study of the average reservoir pressure may support, which led to an increase in oil production by up to 5.5% of the original oil in the tank. so that, the use of water injection is a useful way to increase oil production. Therefore, many of the issues related to this subject valuable of study where the development of new ideas and techniques.


2021 ◽  
Author(s):  
Taras Sergeevich Yushchenko ◽  
Evgeniy Viktorovich Demin ◽  
Rinat Alfredovich Khabibullin ◽  
Konstantin Sergeevich Sorokin ◽  
Mikhail Viktorovich Khachaturyan ◽  
...  

Abstract Wells with extended horizontal wellbore (HW) drilling with multistage hydraulic fracturing (MHF) is necessary for commercial oil production from Bazhenov formation (Vashkevich et al., 2015; Strizhnev, 2019). Today the maximum HW length for Bazhenov formation wells is 1500 m (Strizhnev, 2019, Korobitsyn et al., 2020). In international practice the maximum HW length for shale oil production is around 3000-400 m (Rodionova et al., 2019). Pump Down Perforator (PDP) technology is used for MHF: a liner is run in hole and cemented, then perforation and hydraulic fracturing (HF) are successively performed by stages at equal distances from the end to the beginning of HW to create a branched system of fractures in Bazhenov formation. Performed HF stages are isolated with special packer plugs (insoluble blind, dissolvable blind, insoluble with seat for dissolvable ball or dissolvable with seat for dissolvable ball)) (Mingazov et al., 2020). Consequently, the fluid inflow into the well is occurred along whole HW and the flow rate increases from monotonically from the end to the beginning of HW and has maximum value at last HF stage. The numbers of HF stages are about 24-30 (number of perforating clusters - 100) at one well in Russia and 50 in the world (Alzahabi et al., 2019). One of important parameter during HF is the speed of HF fluid injection into the formation. Tubing outer diameters 114-140 mm. are used in HW to increase the injection rate and reduce friction losses in the well. The flow rate of HF fluid in this case reach to 14-16 m3/min (Ogneva et al., 2020; Astafiev et al., 2015). Monobore wells construction is planned to use with outer diameter 140 mm. A stinger is used as sealing element between tubing and liner to minimizing risk of HF liquids leaks into the annulus (Astafiev et al., 2015). As a result, the inner well diameter from wellhead to bottomhole is around constant in the process of MHF. The pressure in the hydraulic fractures and the collector near fractures after MHF is highly exceeded the initial reservoir pressure. Hence wellhead pressure after MHF in water filled well is about 100-150 bar (Jing Wang et al., 2021). This fact significantly limits downhole well operations because of requires killing (tubing change, let down ESP, etc.). These works are required heavy well killing fluid because of high overpressure. It is undesirable because of it can reduce the fracture conductivity, worse well bottom zone properties and reduce well productivity. Therefore, the well is working at flowing mode in initial period usually until the reservoir pressure in the drainage area is decreased at the hydrostatic level or below (Jing Wang et al., 2021). After that the well can be killing using technical water with a density of 1.01 – 1.07 g/sm3 (the use of well-killing fluid with a density higher than 1.1 g/sm3 is undesirable). The possibility of well flowing working depends on properties of collector and reservoir fluid: High gas-oil ratio (GOR) and reservoir conductivity help well flowing until reservoir pressure drop off hydrostatic pressure.


Author(s):  
A. Kh. Shakhverdiev ◽  
S. V. Arefyev ◽  
A. A. Polishchuk ◽  
B. P. Vaynerman ◽  
R. R. Yunusov ◽  
...  

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.


2013 ◽  
Vol 273 ◽  
pp. 55-59
Author(s):  
Leng Tian ◽  
Ming Xu Ma ◽  
Shun Li He

China has large volumes of low-permeability reservoirs, distributed widely in the Ordos, Karamay and Songliao basins. In the recent decade, a new technology called advanced water injection (AWI), which is to inject water into formation to increase or maintain pressure for 3 to 6 months before oil production, has been applied to efficiently develop low-permeability reservoirs. This paper studies mechanisms and applications of AWI in China. Especially, its resent application in Xifeng oilfield has been described in detail. Most importantly, this paper proposes a simple equation to calculate optimal injected volume of water and pressure rise.


2021 ◽  
Author(s):  
Sudad H Al-Obaidi ◽  
Hofmann M ◽  
Khalaf FH ◽  
Hiba H Alwan

The efficiency of gas injection for developing terrigenous deposits within a multilayer producing object is investigated in this article. According to the results of measurements of the 3D hydrodynamic compositional model, an assessment of the oil recovery factor was made. In the studied conditions, re-injection of the associated gas was found to be the most technologically efficient working agent. The factors contributing to the inefficacy of traditional methods of stimulating oil production such as multistage hydraulic fracturing when used to develop low-permeability reservoirs have been analysed. The factors contributing to the inefficiency of traditional oil-production stimulation methods, such as multistage hydraulic fracturing, have been analysed when they are applied to low-permeability reservoirs. The use of a gas of various compositions is found to be more effective as a working agent for reservoirs with permeability less than 0.005 μm2. Ultimately, the selection of an agent for injection into the reservoir should be driven by the criteria that allow assessing the applicability of the method under specific geological and physical conditions. In multilayer production objects, gas injection efficiency is influenced by a number of factors, in addition to displacement, including the ratio of gas volumes, the degree to which pressure is maintained in each reservoir, as well as how the well is operated. With the increase in production rate from 60 to 90 m3 / day during the re-injection of produced hydrocarbon gas, this study found that the oil recovery factor increased from 0.190 to 0.229. The further increase in flow rate to 150 m3 / day, however, led to a faster gas breakthrough, a decrease in the amount of oil produced, and a decrease in the oil recovery factor to 0.19. Based on the results of the research, methods for stimulating the formation of low-permeability reservoirs were ranked based on their efficacy.


2009 ◽  
Vol 12 (06) ◽  
pp. 865-878 ◽  
Author(s):  
Xin Feng ◽  
Xian-Huan Wen ◽  
Bo Li ◽  
Ming Liu ◽  
Dengen Zhou ◽  
...  

Summary BZ25-1s field in Bohai Bay, China, is characterized as a complex channelized fluvial reservoir in which small meandering channels were deposited at different geological times stacking and cross cutting each other. There are many isolated small reservoir systems following channel distributions. Early production showed steep pressure and production decline. Quick implementation of water injection was needed to arrest the fast production decline and to stabilize reservoir pressure. While designing the water-injection plan, we faced a number of challenges, such as high oil viscosity (˜200 cp), strong heterogeneity, poor reservoir connectivity, complex channel geometry, and irregular well patterns. A workflow integrating geological, well-log, seismic, and dynamic production data was developed to optimize a water injection plan for this field after a short production history. Focuses of this workflow are the selection of injection wells (converted from existing producers), timing of water injection, and the optimization of injection rates. Following the workflow, the optimal water-injection design for the areas around Platforms D and E was developed and quickly implemented within the first year of production. We started with a relatively small water-injection rate and gradually increased the injection rate to avoid the fast water breakthrough and yet to limit the pressure-decline rate. The responses from the water injection were very positive and resulted in stable reservoir pressure and increase of oil production. Before water injection, the production-decline rates were 26 and 47% in Platforms D and E, respectively. After 1 year of water injection, oil-production-decline rates in these two platforms were reduced to 19 and 14%, respectively. The responses of water injection for different well groups were analyzed in a timely fashion and adjustments to injection/production strategies were implemented accordingly. New information revealed from the water-injection response analysis was used to update the geological model to reduce the model uncertainty, as well as to adjust the water-injection strategies for better sweep efficiency. Our experiences showed that such dynamic adjustment of injection and production schedule is very important to achieve better water-injection efficiency for this heavy-oil reservoir with complex channel geometry.


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