Various physico-chemical processes are affecting Alkali Polymer (AP) Flooding. Core floods can be performed to determine ranges for the parameters used in numerical models describing these processes. Because the parameters are uncertain, prior parameter ranges are introduced and the data is conditioned to observed data. It is challenging to determine posterior distributions of the various parameters as they need to be consistent with the different sets of data that are observed (e.g. pressures, oil and water production, chemical concentration at the outlet).

Here, we are applying Machine Learning in a Bayesian Framework to condition parameter ranges to a multitude of observed data.

To generate the response of the parameters, we used a numerical model and applied Latin Hypercube Sampling (2000 simulation runs) from the prior parameter ranges.

To ensure that sufficient parameter combinations of the model comply with various observed data, Machine Learning can be applied. After defining multiple Objective Functions (OF) covering the different observed data (here six different Objective Functions), we used the Random Forest algorithm to generate statistical models for each of the Objective Functions.

Next, parameter combinations which lead to results that are outside of the acceptance limit of the first Objective Function are rejected. Then, resampling is performed and the next Objective Function is applied until the last Objective Function is reached. To account for parameter interactions, the resulting parameter distributions are tested for the limits of all the Objective Functions.

The results show that posterior parameter distributions can be efficiently conditioned to the various sets of observed data. Insensitive parameter ranges are not modified as they are not influenced by the information from the observed data. This is crucial as insensitive parameters in history could become sensitive in the forecast if the production mechanism is changed.

The workflow introduced here can be applied for conditioning parameter ranges of field (re-)development projects to various observed data as well.

Keywords:
machine learning, Bayesian Inference, chemical flooding methods, optimization problem, enhanced recovery, objective function, oil production, experiment, Upstream Oil & Gas, concentration
Subjects:
Well & Reservoir Surveillance and Monitoring, Reservoir Characterization, Fluid Characterization, Reservoir Fluid Dynamics, Improved and Enhanced Recovery, Reservoir Simulation, Formation Evaluation & Management, Unconventional and Complex Reservoirs, Information Management and Systems, Phase behavior and PVT measurements
Copyright 2020, Society of Petroleum Engineers
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