Abstract
After the successful results of the first polymer injection pilot in El Trébol field (started in 2022) that demonstrated substantial bypassed oil after 47-years under waterflood, the next step of the project is to move towards the expansion of polymer injection to other areas. De-risking new potential polymer injection areas has a high impact on the design of the EOR development plan for the entire field.
The objective of this paper is to show the integrated workflow for the 3D Full-Field reservoir modeling containing 405 drilled wells, 850 meters of stratigraphic column and 90 years of production history to unlock EOR potential.
The FullField model area covers approximately 26.4 km2 called "Bloque III" in the El Trébol Field. We tested different facies modelling algorithms to evaluate the lateral connectivity of the sand bodies and different variograms and their azimuth. The workflow for dynamic simulation is divided into 3 parts.1) Geological models section shows the different geological scenarios we tested with different degrees of lateral connectivity of the sand bodies. 2) The dynamic reservoir simulation section shows the different tuning parameters, the variables used for sensitivity analysis, and the optimization variables that we use for history matching, and 3_The forecast section shows the uncertainty parameters that we tested for the forecasting scenarios.
For initialization, we ran cases from the capillary-gravity equilibrium beginning in 1937 (+85 years of production history). We used dummy injector wells to ensure water injection rate at different well intervals during the life of the injection wells. The History matching strategy was based on a partial and incremental history matching according to the development of the field over the years. To design the EOR Field development plan, we determined the sweet-spot polymer injection areas and the target main channels using the in-situ oil tracers which were added to rank the different injection patterns. We also considered the restrictions from roads and surface facilities to make the project more valuable. We used a clustering or grouping process where we used all runs of uncertainty parameter sensitivities to detect groups of curves with similar characteristics in terms of cumulative oil production and maximum oil rate. we use a reduced set of curves that contains one production profile per group to obtain the maximum, average, and minimum incremental oil profiles. The application of tertiary recovery techniques by polymer injection can significantly increase oil production in the field in terms of 8-14% OOIP and prolong its useful life.
The methodology used in this study can be applied to other fields with similar characteristics. The 3D modeling and numerical simulation results allowed us to conceptualize the expansion strategy for polymer injection across the whole field using the model (+50 polymer injector).