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Abstract Unconventional oil wells exhibit rapid decline in oil production rate and low ultimate oil recovery, even though the lateral drilling and completion technology have advanced drastically in the past decade. The petroleum industry has been seeking to develop economic enhanced oil recovery methods to improve the overall recovery factor. The gas huff-n-puff process has been performed and shown the potential of improving the recovery factor from tight oil reservoirs. The objective of the study was to investigate the performance of huff-n-puff EOR in Midland Basin. The studied section of the field contains 2 horizontal producers. The wells produced on primary production for 3 years. The sector was selected as a candidate for performing gas huff-n-puff to enhance the oil recovery factor. Recently, this huff-n-puff EOR project has been performing in the studied volatile oil field in the Permian Basin. In this study, compositional reservoir simulation was used to predict the performance of enhanced oil recovery. A sector model was built for the area selected as the prospective candidate for gas injection. An Embedded Discrete Fracture Model (EDFM) was used for modeling the fractures and stimulated reservoir volume (SRV). A Peng-Robinson equation-of-state model was prepared based on the early produced samples from the wells. A thorough phase behavior analysis was conducted to understand the miscibility of the injected field gas and the in-situ fluid. A Bayesian Assisted History Matching (AHM) algorithm with a neural-network-proxy sampler was applied to quantify uncertainty and find the best model matches for the pair of wells in the Wolfcamp B and C formations of Midland Basin. From 1400 total simulation runs, the AHM algorithm generated 100 solutions that satisfy predefined selection criteria. Even though the primary production were the same for the two wells, the forecasts were dissimilar. It is discussed that the dissimilarity in huff-n-puff performance between two wells is caused by interwell communications. The well interference through fracture hits play an important role in the studied reservoir. The field data show the pressure communication between the two wells. Also, the injected gas was observed in the offset wells about one month after the start of injection. Several long fractures were added to the reservoir model to capture the characteristics of fracture interference. The prospects of EOR were proven decent for the wells of interest. We reported 29% and 82% incremental recovery for the P50 predictions of wells BH and CH, respectively. The results of field operation have been in agreement with the simulation forecasts after two cycles of gas injection and production.