Analytical solution of chemical flooding in heterogeneous non-communicating layers with a focus on low salinity water flooding

Hasan Al-Ibadi, Karl Stephen, Eric Mackay

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

As an enhanced oil recovery method (EOR), chemical flooding has been implemented intensively for some years. Low Salinity WaterFlooding (LSWF) is a method that has become increasingly attractive. The prediction of reservoir behaviour can be made through numerical simulations and greatly helps with field management decisions. Simulations can be costly to run however and also incur numerical errors. Historically, analytical solutions were developed for the flow equations for waterflooding conditions, particularly for non-communicating strata. These have not yet been extended to chemical flooding which we do here, particularly for LSWF. Dispersion effects within layers also affect these solutions and we include these in this work. Using fractional flow theory, we derive a mathematical solution to the flow equations for a set of layers to predict fluid flow and solute transport. Analytical solutions tell us the location of the lead (formation) waterfront in each layer. Previously, we developed a correction to this to include the effects of numerical and physical dispersion, based on one dimensional models. We used a similar correction to predict the location of the second waterfront in each layer which is induced by the chemical's effect on mobility. In this work we show that in multiple non-communicating layers, material balance can be used to deduce the inter-layer relationships of the various fronts that form. This is based on similar analysis developed for waterflooding although the calculations are more complex because of the development of multiple fronts. The result is a predictive tool that we compare to numerical simulations and the precision is very good. Layers with contrasting petrophysical properties and wettability are considered. We also investigate the relationship between the fractional flow, effective salinity range, salinity dispersion and salinity retardation. This work allows us to predict fluids and solute behaviour in reservoirs with non-communicating strata without running a simulator. The recovery factor and vertical sweeping efficiency are also very predictable. This helps us to upscale LSWF by deriving pseudo relative permeability based on our extension of fractional flow and solute transport into such 2D systems.

Original languageEnglish
Title of host publicationSPE Europec Featured at 81st EAGE Conference and Exhibition 2019
PublisherSociety of Petroleum Engineers
ISBN (Electronic)9781613996614
DOIs
Publication statusPublished - 3 Jun 2019
EventSPE Europec Featured at 81st EAGE Conference and Exhibition 2019 - London, United Kingdom
Duration: 3 Jun 20196 Jun 2019

Conference

ConferenceSPE Europec Featured at 81st EAGE Conference and Exhibition 2019
CountryUnited Kingdom
CityLondon
Period3/06/196/06/19

Keywords

  • Chemical waterflooding
  • Heterogeneity in a- petrophysical properties and b- wettability preferential
  • Non-communicating layers
  • Wettability alteration models

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geotechnical Engineering and Engineering Geology
  • Fuel Technology

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  • Cite this

    Al-Ibadi, H., Stephen, K., & Mackay, E. (2019). Analytical solution of chemical flooding in heterogeneous non-communicating layers with a focus on low salinity water flooding. In SPE Europec Featured at 81st EAGE Conference and Exhibition 2019 [SPE-195446-MS] Society of Petroleum Engineers . https://doi.org/10.2118/195446-MS