This thesis work, developed in collaboration with Eni, focuses on the understanding and 3D numerical modeling of the Low Salinity Polymer (LSP) injection technique for Enhanced Oil Recovery (EOR). The aim of the work is to identify a robust tool to model the process and estimate the additional oil recovery that can be achieved by applying it. LSP is an emergent hybrid EOR technique designed to increase the oil production from a field. The process aims to exploit the benefits of the synergistic effect obtained by the injection of polymers, usually dissolved in high salinity water (HSP), and of Low Salinity Water (LSW). This technique allows to uniform the injection front thanks to the high viscosity of the polymeric mixture and to alter, through the low salinity water, the wettability of the rock/oil/water system towards a more favorable condition for the oil mobilization and production. Moreover, the injection of polymer in LSW allows a saving in terms of quantity of polymer used. It is well known that the use of LSW allows to reach high viscosity values with lower polymer concentrations with respect to HSW. The INTERSECT (IX, Schlumberger) reservoir simulator, version 2019.1, has been successfully tested to model the recovery process. Firstly, the activity has been focused on analyzing and modeling the process on a laboratory scale. Then, it has concerned the evaluation of the technique on the reservoir scale, modeling its application in a field of the Eni portfolio. An oil-saturated core experiment has been carried out in the Eni laboratories by injecting LSP following a flushing with HSP. The LSP incremental oil recovery compared to HSP has resulted to be 8%. The experiment has, then, been modeled using IX, activating the option of polymer flooding with salinity dependence, tested in this thesis work for the first time. Subsequently, the results of the experiment modeling have been applied to a sector of the field identified to perform forecast analyses. The conducted simulations have shown that the LSP technique is effective. However, in specific areas of the reservoir, this efficiency is attenuated by the high salinity of the formation water, which generates increases in salinity in the injection area, impairing the LSW benefits and reducing the mixture viscosity. From a preliminary economic analysis, LSP appears to be a cost-competitive technique compared to HSP.
Questo lavoro di tesi, sviluppato in collaborazione con Eni, è incentrato sulla comprensione e sulla modellazione numerica 3D della tecnica di iniezione di polimeri in acqua a bassa salinità (LSP – Low Salinity Polymer) per il recupero avanzato del petrolio (EOR – Enhanced Oil Recovery). Scopo del lavoro è identificare uno strumento robusto per modellare il processo e stimare i recuperi di olio addizionali ottenibili a seguito di una sua applicazione. LSP è una tecnica EOR ibrida emergente volta ad aumentare la produzione di petrolio da un giacimento. Il processo mira a sfruttare i benefici dell’azione sinergica derivanti dall’iniezione di polimeri, solitamente disciolti in acqua ad alta salinità (HSP – High Salinity Polymer), e di acqua a bassa salinità (LSW – Low Salinity Water). Tale tecnica permette di uniformare il fronte di iniezione grazie all’alta viscosità della miscela polimerica e di alterare, attraverso l’acqua a bassa salinità, la bagnabilità del sistema roccia/olio/acqua verso una condizione più favorevole per la mobilitazione e produzione dell’olio. L’iniezione in LSW permette, inoltre, un risparmio in termini di quantità di polimero utilizzata. È infatti noto che l’utilizzo di LSW consente di raggiungere valori di viscosità elevati con concentrazioni minori di polimero rispetto al caso di iniezione in acqua ad elevata salinità. Per la modellazione del processo di recupero è stato testato con successo il simulatore di giacimento INTERSECT (IX, Schlumberger), versione 2019.1. L’attività si è inizialmente concentrata sull’analisi e modellazione del processo su scala di laboratorio, per poi passare a valutarne l’applicazione su scala di giacimento, modellando il processo in un campo del portafoglio Eni. È stato, quindi, eseguito nei laboratori di Eni un esperimento in carota satura di olio iniettando LSP a seguito di un flussaggio con HSP. Il recupero incrementale di petrolio rispetto ad HSP è stato dell’8%. L'esperimento è stato poi modellato utilizzando il simulatore IX, attivando l’opzione di iniezione di miscele polimeriche in acqua a bassa salinità, testata per la prima volta in questo lavoro di tesi. Successivamente, i risultati della modellazione dell’esperimento sono stati applicati ad un settore del giacimento identificato per effettuare analisi previsionali. Le simulazioni svolte evidenziano che la tecnica LSP è efficace. Tuttavia, in determinate aree del giacimento l’efficacia è attenuata dall’alta salinità dell’acqua di formazione che genera incrementi di salinità nella zona di iniezione con conseguenti riduzioni di viscosità della soluzione iniettata. Da una preliminare analisi economica, LSP risulta essere una tecnica competitiva in termini di costi rispetto ad HSP.
Testing an enhanced oil recovery hybrid technique : low salinity polymer injection
STEFANO, ANDREA
2018/2019
Abstract
This thesis work, developed in collaboration with Eni, focuses on the understanding and 3D numerical modeling of the Low Salinity Polymer (LSP) injection technique for Enhanced Oil Recovery (EOR). The aim of the work is to identify a robust tool to model the process and estimate the additional oil recovery that can be achieved by applying it. LSP is an emergent hybrid EOR technique designed to increase the oil production from a field. The process aims to exploit the benefits of the synergistic effect obtained by the injection of polymers, usually dissolved in high salinity water (HSP), and of Low Salinity Water (LSW). This technique allows to uniform the injection front thanks to the high viscosity of the polymeric mixture and to alter, through the low salinity water, the wettability of the rock/oil/water system towards a more favorable condition for the oil mobilization and production. Moreover, the injection of polymer in LSW allows a saving in terms of quantity of polymer used. It is well known that the use of LSW allows to reach high viscosity values with lower polymer concentrations with respect to HSW. The INTERSECT (IX, Schlumberger) reservoir simulator, version 2019.1, has been successfully tested to model the recovery process. Firstly, the activity has been focused on analyzing and modeling the process on a laboratory scale. Then, it has concerned the evaluation of the technique on the reservoir scale, modeling its application in a field of the Eni portfolio. An oil-saturated core experiment has been carried out in the Eni laboratories by injecting LSP following a flushing with HSP. The LSP incremental oil recovery compared to HSP has resulted to be 8%. The experiment has, then, been modeled using IX, activating the option of polymer flooding with salinity dependence, tested in this thesis work for the first time. Subsequently, the results of the experiment modeling have been applied to a sector of the field identified to perform forecast analyses. The conducted simulations have shown that the LSP technique is effective. However, in specific areas of the reservoir, this efficiency is attenuated by the high salinity of the formation water, which generates increases in salinity in the injection area, impairing the LSW benefits and reducing the mixture viscosity. From a preliminary economic analysis, LSP appears to be a cost-competitive technique compared to HSP.| File | Dimensione | Formato | |
|---|---|---|---|
|
TESI_02.11_FINAL.pdf
non accessibile
Descrizione: Tesi
Dimensione
6.17 MB
Formato
Adobe PDF
|
6.17 MB | Adobe PDF | Visualizza/Apri |
I documenti in POLITesi sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
https://hdl.handle.net/10589/151359