Experimental evaluation of shale oil recovery from Eagle Ford core samples by nitrogen gas flooding

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations

Abstract

Production from tight formation resources leads the growth in U.S. crude oil production. Compared with chemical flooding and water flooding, gas injection is a promising EOR approach in shale reservoirs. A limited number of experimental studies concerning gas flooding in the literature focus on unconventional plays. This study is a laboratory investigation of gas flooding to recover light crude oil from nanopermeable shale reservoirs. In this work, the N2 flooding process was applied to Eagle Ford core plugs saturated with dead oil. To investigate the effects of flooding time and injection pressure on the recovery factor, two groups of core-flood tests were performed. In group one, flooding time ranged from 1 to 5 days in increments of 1 day; in the other group, the injection pressure ranged from 1,000 psi to 5,000 psi in increments of 1,000 psi. The experimental setup was monitored using X-ray CT that helped to visualize phase flow and estimate the recovery efficiency during the test. The potential of N2 flooding for improving oil recovery from shale core plugs was examined, and the recovery factor (RF) of each case was presented. The results from group one showed that more oil was produced with a longer flooding time. However, the incremental RF decreased with the increase of flooding time. The oil recovery was significant at the initial period of the recovery process, and a longer flooding time had less effect on extracting more oil. With flooding time constant in 1-day, the results from the second group indicated that RF increased with injection pressure, especially rising pressure, from 1,000 psi to 2,000 psi. The gas breakthrough time became shorter with the increase of injection pressure. The analysis of the CT number showed that the oil recovery process mainly occurred before the gas breakthrough. Once a fluid flow path was established, the injected gas flowed through the limited communication channels; thus, no extra oil could be extracted without increasing the injection pressure. This experimental study illustrates that gas flooding has liquid oil production potential in shale reservoirs.

Original languageEnglish
Title of host publicationSociety of Petroleum Engineers - SPE Improved Oil Recovery Conference
PublisherSociety of Petroleum Engineers (SPE)
ISBN (Electronic)9781613994399
DOIs
StatePublished - 2016
EventSPE Improved Oil Recovery Conference 2016 - Tulsa, United States
Duration: Apr 11 2016Apr 13 2016

Publication series

NameSPE - DOE Improved Oil Recovery Symposium Proceedings
Volume2016-January

Conference

ConferenceSPE Improved Oil Recovery Conference 2016
CountryUnited States
CityTulsa
Period04/11/1604/13/16

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    Yu, Y., & Sheng, J. J. (2016). Experimental evaluation of shale oil recovery from Eagle Ford core samples by nitrogen gas flooding. In Society of Petroleum Engineers - SPE Improved Oil Recovery Conference (SPE - DOE Improved Oil Recovery Symposium Proceedings; Vol. 2016-January). Society of Petroleum Engineers (SPE). https://doi.org/10.2118/179547-ms