Cleanup Model Parameterization, Approximation, and Sensitivity

摘要

Methods and systems for generating and utilizing a proxy model that generates a pumping parameter as a function of contamination. The pumping parameter is descriptive of a pumpout time or volume of fluid to be obtained from a formation by a downhole sampling tool positioned in a wellbore extending into the formation. The contamination is a percentage of the fluid obtained by the downhole sampling tool that is not native to the formation. The proxy model is based on a true model that utilizes true model input parameters that include the pumping parameter, formation parameters descriptive of the formation, and a filtrate parameter descriptive of a drilling fluid utilized to form the wellbore. The output of the true model is the contamination as a function of the pumping parameter. The proxy model utilizes proxy model input parameters each related to one or more of the true model input parameters.

主权项

1. A method comprising:
operating a processing system comprising a processor and a memory to generate a proxy model by utilizing a true numerical model, wherein:
the true model utilizes a plurality of true model input parameters that include:
a pumping parameter descriptive of a pumpout time or volume of fluid to be obtained from a subterranean formation by a downhole sampling tool positioned in a wellbore extending into the subterranean formation;a plurality of formation parameters descriptive of the subterranean formation; anda filtrate parameter descriptive of a drilling fluid utilized to form the wellbore;the output of the true model is contamination of the obtained fluid as a function of the pumping parameter;the proxy model utilizes a plurality of proxy model input parameters each related to one or more of the true model input parameters;the output of the proxy model is the pumping parameter as a function of the contamination; andgenerating the proxy model comprises:
utilizing the true model to generate a plurality of true solutions for each of a plurality of different combinations of values of each of the plurality of true model input parameters; andestimating fitting parameters of the proxy model utilizing the true solutions.