Multivariate Time Series Modelling Approach for Production Forecasting in Unconventional Resources

Abstract

Abstract Evaluating the potential of the unconventional resources is a key for the development of this type of reservoirs. The currently adopted models for the well production forecast including decline curve analysis often fail to capture the complexity of flow performance by over-simplifying it and cannot produce reliable results due to the operational problems and most importantly the inadequate production history. In this study, a deep learning approach is developed to predict the long-term well performance based on a moderate duration of production data. A data-driven procedure was implemented based on deep neural networks for flowrate predication using multivariate inputs. The production forecast was formulated as a time series regression problem where multiple inputs including tubing-head pressure and bottom-hole temperature are used as the input of a reverse model that estimates flow rate. Different recurrent neural networks (RNNs) including Long Short Term Memory, Gated Recurrent Units, and Bidirectional Recurrent Neural Networks were tested in this study to select the most time-efficient and accurate model of production forecasting. The method presented in this paper provided a time efficient process which learned multi-domain sequence and was used to forecast production in unconventional resources. The developed deep learning networks did not require any feature handcrafting and could learn directly form the raw data. Reconstructed and predicted flowrates using deep learning was also used to estimate missing flowrate history. The study showed that deep neural networks have great capability to tolerate noise and optimize computation when multivariate input is used. The technique can also be applied to other type of forecasting problems of prediction of pressure and rate in conventional reservoirs, prediction rate from temperature, and multi-well production forecasting.