Injecting gas into tight formations is considered challenging, especially when dealing with ultra-low permeability values as low as 100 nd. Moreover, well spacing between wells may significantly restrict the injection of gas from one well to another. The huff 'n' puff method may be considered one of the most promising methods for tight oil formations for two reasons: it can be conducted using only one well and it may be utilized in horizontal wells with minimal effort and technical issues. As a result, overcoming the injectivity issues in tight formations and achieving a higher oil recovery factor is possible using huff 'n' puff. Studying the performance of huff 'n' puff techniques under different conditions may lead to a better understanding of improving the oil recovery factor of tight oil reservoirs. This paper studies the optimization process of the huff 'n' puff method in tight oil formations by measuring the impact of injection time, soaking time, production time, and fracture geometry on the gas cycling performance. A compositional simulation study was conducted and three main factors were used to study the performance of huff 'n' puff: formation permeability, distance between fracture stages, and oil recovery factor. Five permeability values, 1 md, 0.1 md, 0.01 md, 0.001 md, and 0.0001 md, were used to build five simulation models, then these models were used to study performance, and define the huff 'n' puff optimization process for each model. The results of the first part of the compositional simulation study showed that the oil recovery was improved when the huff 'n' puff process was applied, even with an ultra-low permeability value. Second, short production and injection time showed better performance compared to long production and injection time. Soaking time showed no significant impact on the huff 'n' puff performance. Hence, it is recommended to perform the huff 'n' puff process with a very short soaking time, or to eliminate the soaking stage. Third, fracture halflength and height had an impact on the huff 'n' puff performance. At a long fracture half-length and height, a higher oil recovery factor was observed. Finally, this study provides insight into the huff 'n' puff process in tight and ultra-tight oil formations and illuminates the best scenarios in which to apply huff 'n' puff.
|State||Published - 2017|
|Event||SPE Abu Dhabi International Petroleum Exhibition and Conference 2017 - Abu Dhabi, United Arab Emirates|
Duration: Nov 13 2017 → Nov 16 2017
|Conference||SPE Abu Dhabi International Petroleum Exhibition and Conference 2017|
|Country/Territory||United Arab Emirates|
|Period||11/13/17 → 11/16/17|