CCUS and Comparison of Oil Recovery by Huff n Puff Gas Injection Using Methane, Carbon Dioxide, Hydrogen and Rich Gas in Shale Oil Reservoirs

Abstract

The objective of this paper is to compare oil recoveries by huff ‘n’ puff gas injection using methane (CH4), carbon dioxide (CO2), hydrogen (H2) and rich gas (70% CH4, 20% C3H8, plus 10% C6H14), and to advance some ideas regarding carbon capture, utilization and storage (CCUS) of CO2, and storage of hydrogen when these gases are used in huff ‘n’ puff operations. The procedure considers a real huff ‘n’ puff pilot well in the Eagle Ford shale of Texas with methane injection. Following history match of the pilot well, the injected gas is switched in the reservoir simulator to CO2, H2 and rich gas. Key to success in this process, is geologic containment, which occurs when large volumes of hydrocarbons remain over geologic time in the windows where they were generated. This is the case of the Eagle Ford shale, where hydrocarbons display an upside-down distribution, with oil on the top, condensate in the middle and dry gas at the bottom. Geologic containment permits the implementation of simultaneous huff ‘n’ puff, utilization and storage of CO2 with nil probabilities of leakage. Results show that huff ‘n’ puff gas injection can significantly increase oil recoveries to be 25-35% of the OOIP (depending on the specific injected gas), compared to about 10% by primary means during the simulation time. The benefits of huff ‘n’ puff gas injection are also applicable in other shale reservoirs where oil, condensate and dry gas present an upside down distribution. One example in Canada is the Duvernay shale. Geologic containment allows adequate and safe storage of CO2 and hydrogen without leaks at the end of the huff ‘n’ puff project. This paper also assesses and corroborates the conclusion that "significant improvements in oil recovery can be obtained by injecting gas at larger rates during shorter periods of time (as opposed to injecting gas at smaller rates during longer periods of time)." The same conclusion holds true for methane, CO2, hydrogen and rich gas injection. The novelty of this work is demonstrating the efficiency of CCUS and huff ‘n’ puff gas injection when geologic containment exists in the shale reservoir. It is a solution where everyone benefits and allows to significantly increase oil recoveries, while providing safe storage of CO2 and H2 without any leaks.

Characteristics of Crude Oil Production in Microscopic Pores of CO2 Huff and Puff in Shale Oil Reservoirs

“…CO 2 huff and puff technology in the United States Bakken shale reservoir, Jianghan oilfield salt shale reservoir, Changqing oilfield Jiyuan tight reservoir field test showed good effect of increasing oil production . For the experimental study of indoor CO 2 huff and puff, some scholars compared the mining effects under N 2 and CO 2 injection by carrying out shale oil huff and puff experiments with N 2 and CO 2 injection, and verified the huge potential of CO 2 huff and puff in improving shale oil recovery. − Also, by studying the effects of permeability, fracture, injection pressure, miscible conditions, and soaking time on the huff and puff effect, the best injection parameters were optimized. , CO 2 has a good extraction effect on shale oil. Some scholars studied the effects of injection pressure, soaking time, and fracture number on supercritical CO 2 extraction for shale oil from shale samples in Shengli Oilfield and found that light components could be extracted easily. − CO 2 also has a strong diffusion effect.…”

Experimental Study on Enhanced Methane Detection Using an MEMS-Pyroelectric Sensor Integrated with a Wavelet Algorithm

“…Methane (CH 4 ), as a potent greenhouse gas, warrants attention because of its significant global warming effect compared to carbon dioxide (CO 2 ). − Recent data shows a concerning surge in global atmospheric CH 4 levels since 2007, with a marked increase from 2014 . Concurrently, with governments increasingly focusing on CO 2 issues and the maturation of carbon capture, utilization, and storage (CCUS) technologies, − breakthroughs have been achieved in practical applications like CO 2 -enhanced oil recovery (CO 2 -EOR), coal bed methane (CO 2 -ECBM), and shale gas (CO 2 -ESG). However, the high pressures required to achieve supercritical CO 2 injection states might inadvertently heighten the risk of natural gas (predominantly CH 4 ) leakages, potentially jeopardizing adjacent ecosystems and communities.…”

Compositional Simulation of CO2 Huff-n-Puff Processes in Tight Oil Reservoirs with Complex Fractures Based on EDFM Technology Considering the Threshold Pressure Gradient

“…Among them, CO 2 injection for huff-n-puff oil recovery is the most widely used method. By injecting CO 2 into the formation, the energy of the formation is replenished, and CO 2 storage and displacement of oil are achieved [52].…”