Design of Alkaline-Polymer Flooding in the Matzen Field, Austria - Technical & Economic R&D Evaluation of the planned AP Pilot

Verena Leitenmüller

Research output: ThesisDoctoral Thesis

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Abstract

Enhanced oil recovery (EOR) techniques enable displacement of trapped oil, which is more difficult to extract than mobile oil & can be displaced by chemical flooding. Alkali-polymer (AP) flooding represents an option in which AP containing water is injected. Injection of alkali solution leads to several chemical reactions, including alkali-oil interaction to generate in-situ soaps (emulsions), alkali-reservoir rock and alkali-water-reaction. Use of alkali-polymer formulations lowers interfacial tension, emulsifies trapped oil & sweeps generated in-situ soap to the producer wells. This thesis yields a precise overview about the implementation of alkali-polymer flooding in the Vienna Basin. Technical & economic studies were conducted to reduce uncertainties of the planned prospect & explain the performance of the used alkali lyes. Implementation of EOR further supports the increase of the ultimate recovery & prolongs the field lifetime of the described oilfield. Different alkali lyes were examined & their performance was verified in different studies. Currently sodium carbonate (Na2CO3) is mostly screened & applied as alkali lye for alkali-polymer/ alkali-polymer-surfactant floods. K2CO3 was additionally examined & showed more promising results than Na2CO3. Usage of co-solvents didn’t enhance in-situ soap generation or reduce emulsion viscosity. Oils from the 8.TH & 16.TH were tested, whereby both reservoirs showed promising results. Phase experiments were carried out to get a better understanding for the in-situ soap generation of the alkalis. In order to find the optimal chemical formulation, the fluid-fluid interaction was examined through viscosity & interfacial tension measurements. Additionally, differences in the in-situ soap generation of the oils could be identified & successfully verified, as well as described through the biodegradation model. Alkali-rock interaction was analyzed to avoid dissolution of the reservoir rock in alkaline environment during injection. Reservoir rock samples were exposed at reservoir temperature for 90 days in autoclaves containing the alkali lyes (NaOH, Na2CO3 and K2CO3). The autoclaves were sampled in periodic time intervals & the aqueous phase was analysed. Furthermore, the interaction of alkalis with gravel pack material (Carbolite® & Swarco® glass beads) was evaluated. Usage of NaOH led to massive alterations and dissolution of the reservoir rock & the gravel pack material, whereas carbonate-based alkalis showed only minor alterations. Treatment of back-produced polymer-containing water (HPAM) is a key task for successful chemical flooding. A water treatment plant in pilot scale was operated, using breakthrough polymer-containing water. The impact of HPAM on a corrugated plate separator, a flotation unit & a nutshell filter was evaluated. Re-injection water quality is crucial for EOR techniques & leads to significant water treatment costs. The achieved results showed no influence on the mechanical treatment step by HPAM, whereas the chemical step (flotation) suffered most, especially when HPAM can’t be removed through the flotation chemicals from the aqueous phase, which results in operative challenges in the nutshell filter. Another chemical package was tested, whereby it was possible to treat successfully breakthrough polymer water. An economic evaluation model for research & development (R&D) projects for the upstream segment was developed. It provides a concept funnel, discusses relevant R&D key performance indicators (KPIs) and combines economic KPIs with R&D KPIs. As environmental aspects become more relevant in the upstream business, it's essential to include them in project evaluations in terms of life cycle assessments. Technological, economic & environmental aspects are combined in this developed R&D model & were tested on the alkali-polymer project. All executed studies verified that use of K2CO3
Translated title of the contributionDesign von Alkali-Polymer Fluten im Matzen-Feld, Österreich - Technische und wirtschaftliche F&E-Evaluierung des geplanten AP-Piloten
Original languageEnglish
QualificationDr.mont.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Posch, Wolfgang, Assessor B (internal)
  • Hofstätter, Herbert, Assessor A (internal)
Publication statusPublished - 2019

Bibliographical note

embargoed until 14-05-2021

Keywords

  • Chemical flooding
  • AP-Flooding
  • Water treatment
  • In-situ soap generation
  • Life cycle assessment
  • K2CO3
  • R&D project maturation funnel
  • Vienna Basin

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