Identification and Modeling of Inter-Reservoir Cross-flow Using a Novel Material Balance Method

Abstract

A detailed material balance study of the Northern Area Deep reservoirs was conducted to address anomalous trends identified from p/Z analyses. The material balance study was conducted using a novel application of Petroleum Experts' MBal software, and determined that previously unrecognised volumes of gas were cross-flowing between reservoirs predominantly behind casing in the wells. The magnitude of the cross-flow volumes significantly impacted well and reservoir performance, but were unable to be modelled or quantified. The approach that was adopted to model the inter-reservoir cross-flow using MBal as a “sub-surface abacus”, whereby injection of gas into the reservoirs was introduced manually to represent influx due to cross-flow. Additional production (on top of allocated produced volumes) was introduced to model the corresponding efflux of gas. Manually maintaining a volumetric balance between the efflux and influx profiles was difficult, but achievable, and provided an internally consistent method to model the complex dynamics of this reservoir system. Detailed simulation studies have been recently conducted on the Northern Area Deep reservoirs and have complemented the findings from this material balance study. The MBal model has been updated regularly with over 6 years of additional production and pressure data, and the model is still holding a good history match. This has provided high confidence in the model's robustness, and validates the adopted methodology, which has broader applications to enable material balance modelling of “non-geological” inter-reservoir cross-flow. The purpose of this article is to present the methods and practices employed in this process and to show how they can be applied to other fields/reservoirs.

Effect of Acetylation on the Physicochemical Properties of Starch Extract from Caladium bicolor

“…Diop et al found that the solubility of maize starch decreased with increasing DS between 1.83 and 2.9. Because of the intricate interplay between the physicochemical properties of acetylated starches and the degree of substitution, this research focuses on the isolation and characterization of C. bicolor acetylated and unmodified starch [16].…”