Quantification of Simulation Model Grid Size Impact on Polymer Flooding Application in Heavy Oil Heterogeneous Reservoir

Abstract

Polymer flooding can be a viable alternative to enhance oil recovery of heavy oil fields. The comparison of water and polymer flooding requires a reliable reservoir numerical model to safely ensure the decision analysis including uncertainties and involving a significant amount of simulation runs. Reservoir engineers usually work-around this problem using fast models to reduce computational time; however, it is important to maintain the reliability of heterogeneous reservoir models. Therefore, the proposed work demonstrates how the grid size impacts on accuracy of results and both the time and computational resources. In addition, it is performed an analysis to establish how the typical physical phenomena related to the polymer flooding impact the applicability of the proposed methodology. A highly heterogeneous heavy oil field is used in our proposed studies. The application is conducted to assist pilot test wells. Initially, the definition of the reference strategy (OTM) is presented. In this case study, the OTM strategy is based on the optimization of location and number of wells. Secondly, the effect of grid size on the process is evaluated through two procedures: (1) DA method: a selection of grid size defined by drainage area of the selected wells; and (2) UP method: upscaling is performed in the simulation model. Then, production parameters resulting from models of both procedures (DA and UP) are compared with OTM results. The definition of which procedure is better to represent the wells of interest is performed. Finally, the impact of three polymer flooding physical phenomena (degradation, adsorption and Non-Newtonian effect) on production results is presented, in order to verify the accuracy of the generated fast models in maintained considering these effects. The DA method present good accuracy for reservoir response compared to the reference OTM results. Differently, UP models are not as accurate as DA models for production results indicators. In conclusion, the application of the methodology allows choosing the DA over the UP technique to support our decision in the investigated recovery methods, showing a reliable and fast procedure. Finally, this procedure shows excellent applicability and robustness when a typical polymer flooding study is carried out: the evaluation of physical phenomena impact on production results based on wells of interest.

Application of horizontal well discontinuous chemical flooding technology in Bohai oilfield

“…Rego FB, Botechia VE, etc. conducted grid quantitative calculation on the sweep effect of polymer flooding in heterogeneous heavy oil reservoirs, and analyzed the adaptability and accuracy of this algorithm in the process of polymer flooding in heterogeneous reservoirs (Rego et al, 2016). Hussein Hoteit established a dynamic change model of permeability during chemical flooding, which can calculate the resistance coefficient during chemical flooding and the residual resistance coefficient of subsequent water flooding .…”

Modelos rápidos de simulação aplicados à Injeção de polímeros em reservatórios heterogêneos

“…No último capítulo são apresentadas as conclusões deste trabalho e também sugestões para trabalhos futuros. REGO et al, 2016). Desta forma, é possível manter a confiabilidade dos resultados para uma determinada região de forma ágil, diminuindo o tempo de cada simulação a ser realizada pelo estudo.…”

“…Segundo Rego et al (2016), alguns dos desafios típicos para a seleção de estratégias de produção relacionados à simulação numérica de reservatórios são:…”