Statistical Approach to Forecasting Gas-Oil Ratios & Solution Gas Production for Shale Oil Reser

Date: Tuesday, 6 December 2016 Speaker: Dr. John Lee, Ph.D. Energy Navigator Location: Calgary Petroleum Club Time: 11:30 - 1:00 pm Cost: $45 SPE Members, $55 Non-members, $15 Students

This presentation will discuss a novel method of forecasting oil and gas production from liquid-rich (volatile oil) shale reservoirs using a statistical technique, “Principal Components Methodology (PCM).”

In our study, we simulated production of fluids with different compositions for 30 years with the aid of a commercial compositional simulator. We then applied PCM to the production data from several representative wells by determining the principal components of the production profiles. These principal components were then used to forecast oil production and gas-oil ratios for wells with production histories ranging from 0.5 to 3 years, and the results were compared to simulated data. Following this validation of the methodology, we then applied PCM to field data and further validated the method using hind-casting.

Various factors, most notably multi-phase flow effects, have plagued the task of forecasting production from liquid-rich shale reservoirs. Neither traditional nor more recent decline curve analysis (DCA) methods have been completely adequate. The PCM method enables us to obtain the production decline structure that best captures the variance in the data from the representative wells considered. This new technique eliminates the need for parameters like the Arps’ hyperbolic decline exponents (b values) and the task of switching from one DCA model to another when flow regimes change. It also allows us to forecast production without necessarily using diagnostic plots. With PCM, we have been able to forecast oil and gas production from shale reservoirs with reasonable accuracy.