Predicting Waterflooding Performance in Low-Permeability Reservoirs With Linear Dynamical Systems

SPE Journal ◽  
2017 ◽  
Vol 22 (05) ◽  
pp. 1596-1608 ◽  
Author(s):  
Dashun Wang ◽  
Di Niu ◽  
Huazhou Andy Li

Summary Several interwell connectivity models such as multiple linear regression (MLR) and the capacitance model (CM) have been proposed to model waterflooding performance in high-permeability reservoirs on the basis of observed production data. However, the existing methods are not effective at characterizing the behavior of transient flows that are prevalent in low-permeability reservoirs. This paper presents a novel dynamic waterflooding model that is based on linear dynamical systems (LDSs) to characterize the injection/production relationships in an oil field during both stationary and nonstationary production phases. We leverage a state-space model (SSM), in which the changing rates of control volumes between injector/producer pairs in the reservoir of interest serve as time-varying hidden states, depending on the reservoir condition. Thus, the model can better characterize the transient dynamics in low-permeability reservoirs. We propose a self-learning procedure for the model to train its parameters as well as the evolution of the hidden states only on the basis of past observations of injection and production rates. We tested the LDS method in comparison with the state-of-the-art CM method in a wide range of synthetic reservoir models including both high-permeability and low-permeability reservoirs, as well as various dynamic scenarios involving varying bottomhole pressure (BHP) of producers, injector shut-ins, and reservoirs of larger scales. We also tested LDS on the real production data collected from Changqing oil field containing low-permeability formations. Testing results demonstrate that an LDS significantly outperforms CM in terms of modeling and predicting waterflooding performance in low-permeability reservoirs and various dynamic scenarios.

2014 ◽  
Vol 644-650 ◽  
pp. 5065-5070
Author(s):  
Shuai Jiang ◽  
Zheng Ming Yang ◽  
Xue Wei Liu ◽  
Meng Ting Wang ◽  
Qian Zhang

With the development of the global oil industry,the production of the normal or high permeability reservoirs decline rapidly. Therefore, more and more low permeability reservoirs are used to the production stimulation. The oilfields overseas make great contribution to CNPC. The HF oilfield is one oilfield that the CNPC have in overseas. The HF oilfield is mainly the low permeability carbonate reservoirs which make it not easy to economically exploit. Due to the reason that the low permeability carbonate reservoirs present small porosity and the fluid’s flow situation in the low permeability carbonate reservoirs, the flow doesn't obey the Darcy's law. Thus it is greatly necessary to study the non-Darcy percolation characteristics. In this paper, the HF ‘s low permeability is tested and the threshold pressure gradient test is finished ,according to the experiment results, the nonlinear percolation ‘s law ,which is suited to HF-oil field , is illustrated and the reservoir classification is achieved.


Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 600 ◽  
Author(s):  
Long ◽  
Wang ◽  
Zhu ◽  
Huang ◽  
Leng ◽  
...  

Polymeric nanoparticle suspension is a newly developed oil-displacing agent for enhanced oil recovery (EOR) in low-permeability reservoirs. In this work, SiO2/P(MBAAm-co-AM) polymeric nanoparticles were successfully synthesized by a simple distillation–precipitation polymerization method. Due to the introduction of polymer, the SiO2/P(MBAAm-co-AM) nanoparticles show a favorable swelling performance in aqueous solution, and their particle sizes increase from 631 to 1258 nm as the swelling times increase from 24 to 120 h. The apparent viscosity of SiO2/P(MBAAm-co-AM) suspension increases with an increase of mass concentration and swelling time, whereas it decreases as the salinity and temperature increase. The SiO2/P(MBAAm-co-AM) suspension behaves like a non-Newtonian fluid at lower shear rates, yet like a Newtonian fluid at shear rates greater than 300 s−1. The EOR tests of the SiO2/P(MBAAm-co-AM) suspension in heterogeneous, low-permeability cores show that SiO2/P(MBAAm-co-AM) nanoparticles can effectively improve the sweep efficiency and recover more residual oils. A high permeability ratio can result in a high incremental oil recovery in parallel cores. With an increase of the permeability ratio of parallel cores from 1.40 to 15.49, the ratios of incremental oil recoveries (low permeability/high permeability) change from 7.69/4.61 to 23.61/8.46. This work demonstrates that this SiO2/P(MBAAm-co-AM) suspension is an excellent conformance control agent for EOR in heterogeneous, low-permeability reservoirs. The findings of this study can help to further the understanding of the mechanisms of EOR using SiO2/P(MBAAm-co-AM) suspension in heterogeneous, low-permeability reservoirs.


2011 ◽  
Vol 317-319 ◽  
pp. 2432-2435
Author(s):  
Yu Xue Sun ◽  
Fei Yao ◽  
Jing Yuan Zhao

In the process of low-permeability sandstone reservoir exploitation, stress sensitivity takes place with the effective stress rises gradually, which will cause permeability decline. Allowing to the condition of in-situ stress, the study and experiment on the rock core in Jilin oil field Fuxin326 oil layer are presented. The experimental results show that the stress sensitivity of this oil layer is small; the regularity of permeability changes is in accordance with exponential function. The stress sensitivity of high permeability core is larger than that of low permeability core. Moreover, experimental and theoretical analysis shows that low permeability core has a larger permeability loss than high permeability core in loading and unloading process where elastic plastic deformation of rock will happen, which is the major reason that permeability loss can not return completely.


2010 ◽  
Vol 20 (09) ◽  
pp. 2795-2808 ◽  
Author(s):  
JOSEP FERRER ◽  
M. DOLORS MAGRET ◽  
MARTA PEÑA

Piecewise linear systems constitute a class of nonlinear systems which have recently attracted the interest of researchers because of their interesting properties and the wide range of applications from which they arise. Different authors have used reduced forms when studying these systems, mostly in the case where they are observable. In this work, we focus on bimodal continuous dynamical systems (those consisting of two linear systems on each side of a given hyperplane, having continuous dynamics along that hyperplane) depending on two or three state variables, which are the most common piecewise linear systems found in practice. Reduced forms are obtained for general systems, not necessarily observable. As an application, we calculate the dimension of the equivalence classes.


2020 ◽  
Vol 17 (34) ◽  
pp. 892-904
Author(s):  
Zinon A KUANGALIEV ◽  
Gulsin S DOSKASIYEVA ◽  
Altynbek S MARDANOV

The main part of Russia's hard-to-recover reserves is 73% for low-grade and carbonate reservoirs, 12% for high-viscosity oil, about 15% of extensive sub-gas zones of oil and gas deposits and 7% of reservoirs lying at great depths. The development of such stocks with the usage of traditional technologies is economically inefficient. It requires the application of new technologies for their development and fundamentally new approaches to design, taking into account the features of extraction of hard-to-extract reserves (HtER). The purpose of this research is to find ways to improve the performance of low-permeability reservoirs. To accomplish this task, the Novobogatinsk South-Eastern Oil Field has been taken as an example and described. The necessary properties of production facilities in the field are highlighted, along with economic feasibility and technological efficiency. The reserves involved in the development are determined and, thanks to the knowledge of the geological oil reserves of the deposits, the potential oil recovery factor is calculated with the existing development technology. As a result of the research, development options were worked out with the results of the calculation of design indicators for the field as a whole. The comparison of oil recovery schedules and ORI, as well as the layout of wells, have been presented. As a result of the study, a description of 3 options for the development of design indicators for the field as a whole is given. The figures show oil production graphs, as well as location patterns. The authors of the study conclude which of the recommended development options can help extract maximum oil reserves.


2018 ◽  
Vol 785 ◽  
pp. 34-39
Author(s):  
Vadim Aleksandrov ◽  
Marsel Kadyrov ◽  
Andrey Ponomarev ◽  
Denis Drugov ◽  
Mikhail Zavatskij

One of the acutest problems in the oil and gas industry is the efficient development of low-permeability reservoirs in Jurassic sediments. At that, the choice of efficient technologies can be made basing on the analysis of field-geological and laboratory data, as well as the analysis of previously conducted activities with account of facies genesis of reservoir rocks in the wells, where the geotechnical activities (GTA) are realized. The research objective is the assessment of bottomhole formation zone (BFZ) results for the YUS11 development wells at the Fainsk oil field with the application of hydrocarbon solvents and acid compounds. Using detailed field-geological analysis, the data obtained after the processing of a bottomhole formation area of the development wells with the application of hydrocarbon solvents and acid compounds was assessed.


2013 ◽  
Vol 274 ◽  
pp. 153-156
Author(s):  
Rong Hua Li ◽  
Jun Ting Zhang ◽  
Cheng Lin Zhang ◽  
Huan Huan Zhang ◽  
Peng Qu

Layer system subdivision and adjustment is applied in oilfield development to ease the contradiction in inner-layer and interlayer and implement separated layer water flooding well, which is a major adjustment measure to improve developing effects. YSL is a typical low-permeability oil field, whose petrophysics is poor, and which exist many problems, such as apparent contradictions between layers, and poor development effects through separated zone water injection and so on. In this article, the thickness of barriers, injection profile, permeability contrast and remaining oil distribution are analyzed comprehensively. So a reasonable method is also proposed. Much weakness that factors are not comprehensive in adjustment method and that the problems in the development process are not accurately reflected is overcome, which exists in the past methods. The adjustment means can utilize poor thin layers better, reduce invalid water injection and ease the contradictions between layer, and oilfield development effects are improved eventually. It is a reference and guidance for other blocks or oilfield which exist the same problems.


2021 ◽  
pp. 014459872199560
Author(s):  
Zhaosheng Wang ◽  
Lianbo Zeng ◽  
Jiangtao Yu ◽  
Zhenguo Zhang ◽  
Siyu Yang ◽  
...  

Carbon dioxide (CO2) flooding is an effective method to enhance oil recovery in low-permeability reservoirs. Studying key geological factors controlling oil displacement efficiency is of great significance to the CO2 injection scheme design in low-permeability reservoirs. Focusing on low-permeable H reservoir in Songliao Basin, China, this paper describes the contact and connection of sand bodies, natural fractures and high-permeability zones with core samples, log data and experiment firstly. After that, the impact of interaction of sand body connection, natural fracture and high-permeability zone on oil displacement efficiency is determined by using geological and dynamic data in CO2 injection area. Results indicate that the connection of single sand bodies between injectors and producters wells primarily controls CO2 flooding in low-permeability reservoirs. Furthermore, coupling of sand body connection, natural fractures and high-permeability zones is the key geological factor governing oil displacement efficiency of CO2 injection in low-permeability reservoirs, where well or generally-connected sand bodies can improve the efficiency significantly. Meanwhile, the dominant seepage channels in other directions have no influence on producers, which is beneficial to improve CO2 flooding efficiency.


Author(s):  
Вадим Александрович Чемеков ◽  
Артем Маратович Шагиахметов

Сейчас, когда истощение базы углеводородного сырья происходит все быстрее, разработка залежей низкопроницаемых коллекторов требует дополнительных методов стандартных способов эксплуатации. Одним из методов добычи трудноизвлекаемых запасов является многостадийный гидроразрыв пласта, который позволяет существенно увеличить эффективность эксплуатации горизонтальных скважин. Now, when the depletion of the hydrocarbon base is faster, the development of low-permeability reservoirs requires additional methods of standard operating methods. One of the methods for extracting hard-to-recover reserves is multi-stage hydraulic fracturing, which can significantly increase the efficiency of horizontal wells.


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