Theme 1 focuses on understanding, modeling, and upscaling the microscopic and macroscopic displacement efficiency when various EOR fluids are injected into a porous rock.
We put equal emphasis on Enhanced Oil Recovery (EOR) operations in chalk and sandstone formations. The environmental impact of the EOR methods will be assessed throughout the run of the Centre.
Primary objective of Theme 1
Optimize the microscopic and macroscopic displacement efficiency in a porous rock from the chemical and mineral compositions of pore fluids and rock grains, considering the sustained diagenesis and translate this knowledge to industry applications.
Secondary objectives of Theme 1
- Develop methods of upscaling pore and core oil recovery to field scale
- Develop methods that can predict transport of chemical compounds from core to field
- A fundamental understanding of wettability and its role in porous media flow from pore-, to core and field scale
- An understanding of the impact and long term effect of EOR technologies on the reservoir
- Evaluate the environmental impact of the EOR methods.
There are several well-studied chemical injection technologies applicable for the fields on the Norwegian Continental Shelf. Thorough laboratory- and modeling studies have been performed, but there are still research challenges.
Field or pilot tests have been rare due to uncertainty of the potential for improving the recovery. Most crucially in order to improve all methods is a proper simulation of the mechanisms on a field scale.
These are the tasks in Theme 1
Task 1: Core scale projects
Task leader: Arne Stavland, research manager, NORCE (email@example.com)
At core scale we focus on IOR mechanisms; improving macroscopic and microscopic sweep efficiency. The key research questions are how chemicals travels through a porous media, the role of mineral wettability in determining the fluid flow in porous media and how to model the chemical systems.
The project DOUCS – Deliverable of an Unbeatable Core Scale Simulator aims to develop a tool for improved simulation of EOR processes at the core scale. Strongly related projects are the two postdoc projects on Integrated EOR for Heterogeneous Reservoirs by postdoc Bergit Brattekås and Description of the Rheological Properties of Complex Fluids Based on the Kinetic Theory by postdoc Dmitry Shogin. In addition, the two PhD projects, Core scale modeling of EOR Transport by PhD student Oddbjørn Nødland and Mechanisms and Flow of non-Newtonian Fluids in Porous Media by PhD student Irene Ringen.
The project Core plug preparation procedures addresses the importance of representative wettability conditions in SCAL and EOR -experiments and aims to develop methods to determine whether reservoir core plugs are contaminated by mud. This project is strongly related to the project Wettability estimation by oil adsorption by the PhD candidate Samuel Erzuah. In the PhD project the main focus is to use a new experimental technique (QCM-D) to measure oil adsorption on mineral surfaces. The QCM-D technique relates the vibrational frequency of a mineral plate to the mass of the adsorbent on the plate.
The project Application of metallic Nanoparticles for Enhanced Oil Recovery, by PhD student Kun Guo, aims to in-situ catalyze decomposition of heavy hydrocarbons leading to lower oil viscosity and improved mobility.
Three PhD projects addresses the effect of pore fluids on the geo-mechanical and wetting properties of chalk materials. The chalk matrix is sensitive to physical forces such as the overburden and pore fluid pressure and chemical interactions inside the cores. In the PhD work we try to relate macroscopic observable oil production, permeability change, and deformation to microscopic changes in the geochemistry by methods developed in Task 2. The PhD thesis are: (i) Thermal properties of reservoir rocks, role of pore fluids, minerals and diagenesis – a comparative study of two differently indurated chalks by PhD student Tijana Voake, (ii) Permeability and stress state by PhD student Emanuela I Kallesten where a close collaboration to Task 2 exist in regard of the application of the developed ‘tool box’ for analytical studies of mineralogical changes in samples of EOR experiments, (iii) How does wetting property dictate the mechanical strength of chalk at in-situ stress, temperature and pore pressure conditions, by PhD student Jaspreet Singh Sachdeva.
Task 2: Mineral fluid reactions at nano/submicron scale
Task leader: Udo Zimmermann, Professor, UiS (firstname.lastname@example.org)
Task 2 focuses on the mineralogical and geological background of tested rock material for a variety of core flooding experiments and to search for the most economic and fastest toolbox of methods to gain substantial results within this objective. Moreover, the testing and application of novel methods produces more insights into chalk and chalk reservoirs while it trains in the same time young researchers on top edge methods and applications.
In this research, we apply state-of-the-art methods, which in several cases had been innovative for the Centre and have been applied in other tasks. We also could show that the same toolbox is useful for the understanding of processes during polymer injection in sandstones.
The task has a well-developed international network including centers of excellence on top level. These institutions are regularly visited by our PhD/MSc students for training and knowledge transfer. Therefore, we can assure that all analytical steps are well controlled and documented when carried out at our collaborating institutions.
The main expertise is related to micron- and nano-sized interactions between fluids and rocks in the framework of IOR research. We apply traditional and non-traditional methods to maintain a strong research position and to assist the other tasks with novel data. We demonstrated the use of automated electron microscopy as a very important and quick tool in regard of the understanding of reservoir rocks. The identification of processes within the scale of micro- and nano-porosity is a very new research focus on a global scale, with a strong potential for a variety of applications, besides IOR, like storage, for example. We also apply new stable isotope methods (e.g. Mo, Cr and Zn) to samples to understand the origin of the reservoirs better, as the depositional parameter seem to influence a wide range of mineralogical processes during flooding of reservoir rocks.
The results are substantial for modelling of pore scale simulations and the understanding of porosity and permeability evolution in Tasks 1 and 3 based on the insights into mineralogical alteration in reservoir rocks. The interdependency of rock mechanics and mineralogy is a central focus of this task as significant mineralogical alterations happen after flooding with ‘Smart Water’ or polymers.
It is obvious that the geological results are paramount for the understanding of subsidence and future modelling of sedimentary basin evolution at the NCS and substantial when evaluating environmental constraints of IOR methodologies and storage options at the same time.
Task 3: Pore scale
Task leader: Espen Jettestuen, research manager, NORCE (email@example.com)
The objective of the pore scale task is to identity mechanisms that influence fluid transport, chemical reactions, and oil recovery. The main topics in this task has been to study the behaviors of polymers and the effect of water chemistry on the strength and structure of the pore space.
In the project "Description of the Rheological Properties of Complex Fluids Based on the Kinetic Theory" kinetic theory is used to predict the polymer fluid rheology from the microscopic description of the polymer. This method has now been used to consider salinity effects and mechanical degradation of the polymer. Journal publications on both topics are planned. Project manager Dmitry Shogin was awarded a VISTA scholarship extending the project duration to 2022. Two PhD students are joining the project. The experimental PhD, Siv Marie Åsen, has started early 2018. The numerical PhD started August 2018.
The PhD project "Experimental investigation of fluid chemistry effect on adhesive properties of calcite grains" studies the adhesion of calcite-calcite surfaces in different brines using atomic force microscopy and atomic force apparatus. These measurements techniques have been extended to work on rough surfaces so that the adhesion force can also be studied as a function of surface topology. The PhD student has received a six months extension to finish the thesis. An article has been published in "Langimur".
Numerical methods are developed in the project "Micro Scale Simulation of Polymer Solutions" to study fluids with non-Newtonian rheology’s on the pore scale. The simulations will be used to understand which polymer properties are important on the Darcy scale. The stability of the code has been improved and can now handle viscosity ratios of 1000-5000. An article has been published in "Physics of Fluids".
The project "Pore scale simulation of multiphase flow in an evolving pore scale" uses a lattice Boltzmann numerical method to study how pore space and wetting are affect by fluid chemistry and flow rates. This method is used on real chalk geometries previous acquired as part of the project. The numerical model has been updated with an improved phase-separation algorithm capable of handling dynamic wetting properties and used to simulate both spontaneous imbibition and relative permeability setups. The results have been presented at the EAGE 2018 Workshop in Copenhagen and EGU 2018 in Vienna.
Task 4: Upscaling and environmental impact
Task leader: Aksel Hiorth, Professor, UiS (firstname.lastname@example.org)
In this task there are two research projects, and two PhD projects. The IORSim project is a collaborative effort between IFE, NORCE, and UiS to develop a simulator that can bridge the gap between the research prototype simulators and industry standard reservoir simulators. IORSim uses the output from ECLIPSE to predict the effect of IOR chemicals not currently included in ECLIPSE. The models implemented in IORSim are based on developments done in Task 1, 2 and 3. Currently the main numerical challenges are to improve the speed of IORSim and to reduce the numerical dispersion. IORSim now runs the Snorre field case, but there are some deviations between IORSim and ECLIPSE. We believe this is due to crossflow in wells, this will be implemented during the next couple of months we. Parallel to this activity we are improving the numerical scheme in IORSim by taking into account higher order terms in the discretization of the transport equations and allowing for local grid refinement in IORSim. We hope to have a successful simulation of the sodium silicate pilot during the spring 2019.
The large (yard) scale project is led by Halliburton, and there is a very good collaboration with activities in Task 1. Chemical systems are tested in the lab, and the plan is to test the same systems on a larger scale as a medium scale before a pilot or full field injection. After the success of Yard Test Phase I (polymer degradation in chokes) there was great interest from TC members to continue to investigate polymer degradation in large sand packs (10 m scale). To better design a yard test, we first investigated polymer degradation in the lab. The lab tests clearly demonstrated polymer degradation increased by increasing the length. However, the degradation is associated with high pressure gradients, on the order of 100 bar/meter, which at field scale is not realistic. These findings had the implication that it is very difficult due to the high-pressure gradients and flow rates to reproduce these experiments at larger scale (large in this context means larger cross section). There was also a concern that a large scale test would not give us any new insight than already gained from the lab investigations. Based on these findings a workshop was organized by Haliburton and new concepts were discussed. Based on the workshop we decided to investigate chemical systems to block high flow pathways – thermal triggered (associative) polymers. Plans for phase II are completed, and the budget decided. We expect the Phase II to start this year and produce data.
The two PhD projects are progressing well, one of the PhD students, Remya Ravindran Nair, has presented 14 times at international conferences and published 5 papers. She will defend the thesis during the spring/summer 2018. The focus has been to determine the efficiency of membranes and membrane system to produce smart water offshore. The second PhD project "Environmental fate and effects of EOR polymers" is led by PhD student Eystein Opsahl. Much work has been spent on establishing lab procedures, which is challenging as the polymer systems are challenging to work with from a toxicological viewpoint.