Researchers from both industry and academia have studied the tight oil resources intensively in the past decade since the successfully development of Bakken Shale and Eagle Ford Shale and made tremendous progress. It has been recognized that locating the sweet spots in the regionally pervasive plays is of utter significance. However, we are still struggling to determine whether the dominant control on shale well productivity is geologic or technical. Given certain geological properties, what is the best completion strategy?
Most of the previous studies either analyze the completion data alone or divide the entire play into different data clusters by map coordinates and depth, which may neglect the heterogeneity in thickness and reservoir quality parameters. In our study, we first conducted stratigraphic and petrophysical analyses, using the regional variation in depth, thickness, porosity, and water saturation to capture the regional heterogeneity in the Bakken Shale Petroleum System. We selected approximately 2,000 horizontal wells targeting Mid Bakken Formation with detailed completion records and initial production dates during 2013 and 2014. Completion data inputs include normalized stage length, stage counts, normalized volume of fluid, and normalized volume of proppant.
We investigated the relative importance of the geological and completion features exerts on the first-year production. Then we built the neural network model to identify the relationship between the first-year oil production with the important features. We separated the data into three sets for training, validation, and testing. After we trained the model using the training and validation set, we tested the model to estimate its robustness. Then, with given geological input, we provided the completion strategy that optimizes the first-year production.
The developed technique provides a method to identify the best well location, understand the effectiveness of the completion strategy, and predict the well production. While the data used came from wells in the Bakken shale, the methodology applies in a similar way to other tight oil plays.
