Quantitative Evaluation of Recovery Mechanisms for Huff-n-puff Gas Injection in Unconventional Reservoirs

Hoffman, B. Todd; Reichhardt, David

doi:10.15530/urtec-2019-147

Cited by 27 publications

(15 citation statements)

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“…The study confirmed that diffusion is the most important parameter in CO 2 injection EOR. Hoffman and Reichhardt, using computational simulation, assessed the role of recovery mechanisms of viscosity reduction, oil expansion, vaporization, and pressure support during H-n-P procedures in the EF reservoir. They proved that vaporization is the most significant for high gas-oil ratio (GOR) reservoirs while oil swelling is the most significant for low-GOR reservoirs.…”

Section: Gas-eor Mechanism In Shale/tight Reservoirsmentioning

confidence: 99%

Huff-n-Puff Technology for Enhanced Oil Recovery in Shale/Tight Oil Reservoirs: Progress, Gaps, and Perspectives

et al. 2021

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In recent times, particularly in the 21st century, there has been an alarming increase in the demand for global energy, along with continuous depletion in conventional oil reservoirs. This necessity has incentivized interested scholars and operators worldwide to seek alternative oil resources. To secure such accelerating energy demand, considerable effort has been directed toward the development of previously unconventional oil formations that, in past decades, had remained sidelined. Although shale oil reservoirs have seen tremendous success over the past decade, the continued challenges of rapidly declining oil flow rates and oil retention in the pores continuously persist. Substantial attempts have been made to improve shale-bypassed oil recovery; however, there is little data about the accessibility on recovery mechanisms, especially in the oil field. Furthermore, approachesparticularly, Huff-n-Puff (H-n-P) experiments using conventional proceduresfail to properly represent field conditions and they generate deceptive findings, because the utilized cores are not simulated under realistic reservoir conditions, leaving the significance of critical factors unclear. Therefore, this review study comprehensively and specifically discusses the feasibility of enhanced oil recovery (EOR) methods in unconventional oil reservoirs. Beside addressing the validity of the currently applied H-n-P technology in shale/tight oil reservoirs and underlining some critical gaps regarding laboratory results, modified technology is proposed in this paper for a better field future performance. The study is divided into sections, and each section analyzes the role of one specific H-n-P portion in detail, such as preferable injected solvents, their mechanisms, and critical factors affecting H-n-P recovery. The exceptions to this are the first and second sections, which provide a brief introduction about shale and tight oil reservoirs, a history of applied technology, and the method’s current problem statement. In the Introduction section, the authors will justify why this Review fills a critical gap in the field. Within the assessment study, great focus is given to the H-n-P technique, its parameters, and effective processes. In the final sections, carefully chosen experimental results and tools are reviewed to highlight the controversy and state “the gap”.

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Section: Gas-eor Mechanism In Shale/tight Reservoirsmentioning

confidence: 99%

Huff-n-Puff Technology for Enhanced Oil Recovery in Shale/Tight Oil Reservoirs: Progress, Gaps, and Perspectives

et al. 2021

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“…After an optimum soaking time, the well will return to production (puff process) (Zhou et al, 2018). Using the huff and puff EOR process can activate production mechanisms such as viscosity reduction (Sayegh and Maini, 1984), oil swelling (Hoffman and Reichhardt, 2019), reservoir re-pressurization (Zhang et al, 2004), and solution gas drive (Monger et al, 1991). There are many parameters that can affect the huff and puff performance, including soaking time, injection rate, injection pressure, number of cycles, and injection fluid composition, which need to be optimized for its field application to achieve maximum oil recovery or profits.…”

Section: Introductionmentioning

confidence: 99%

Performance of CO2 Foam Huff and Puff in Tight Oil Reservoirs

2022

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The challenges associated with unconventional reservoirs are related to their intrinsic nature: extremely low porosity and permeability. Combinations of horizontal wells and multistage hydraulic fracturing techniques have been developed to overcome the production obstacles and unlock the vast amount of oil in place in such formations. However, oil production still exhibits a sharp decline within the first 2 years after the stimulation, leading to an oil recovery of less than 15%. Thus, enhanced oil recovery methods need to be investigated to further increase the production rates and the recovery. In this study, laboratory experiments and numerical simulations were conducted to evaluate the performance of the CO2 foam huff and puff process and its impacts on oil recovery in tight oil formations. More specifically, the foam half-life was measured as a function of surfactant concentration and followed by the foam drainage ratio and its rheological properties in the subsequent tests. Reservoir simulations were conducted using the lab data and the field data collected from Cardium formation. Sensitivity analyses were finally carried out to investigate the effects of controlling variables on the CO2 foam performance. Experimental results revealed that the optimal surfactant concentration was found to be 0.2%, which is the critical micelle concentration point. Simulation results show that CO2 foam huff and puff can increase the oil recovery by more than 11% compared to that of the primary production. Moreover, sensitivity analyses show that the production time, injection time, and soaking time are the main effecting parameters, while the injection rate and the incremental injection rate are less important.

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“…And the process can be miscible or immiscible, depending on the reservoir pressure and the composition of the injected gas and the oil. The primary recovery mechanisms for such process are oil swelling, oil viscosity reduction, vaporization, and pressure support [5]. It is documented that several hundred wells have been converted to cyclic gas injection up to date in the Eagle Ford Shale play in the United States with pleasant performance reported.…”

Section: Introductionmentioning

confidence: 99%

Conformance Control for Tight Oil Cyclic Gas Injection Using Foam

et al. 2022

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Cyclic gas injection has been proven to be an effective enhanced oil recovery (EOR) technique for tight oil reservoirs. During such processes, we expect recovery mechanisms such as oil swelling, oil viscosity reduction, vaporization, and pressure support, which highly relies on the successful conformance control of the injected gas. In this work, we present the numerical simulation study of using foam for improving the conformance control of cyclic gas injection in tight oil reservoir. We focus on improving two categories of conformance control problems using foam, making the injection profile for single well more evenly distributed and mitigating the gas breakthrough to adjacent wells through the connected hydraulic fractures in a multiwell setting. The simulation results show that foam has shown major impact in improving the gas conformance control in both cases. Typical recovery factor improvements are estimated to be up to 1% for lean gas injection in this tight oil reservoir. In conclusion, we have demonstrated the great potential of using foam to improve the conformance in tight oil cyclic gas injection process.

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Quantitative Evaluation of Recovery Mechanisms for Huff-n-puff Gas Injection in Unconventional Reservoirs

Cited by 27 publications

References 0 publications

Huff-n-Puff Technology for Enhanced Oil Recovery in Shale/Tight Oil Reservoirs: Progress, Gaps, and Perspectives

Huff-n-Puff Technology for Enhanced Oil Recovery in Shale/Tight Oil Reservoirs: Progress, Gaps, and Perspectives

Performance of CO2 Foam Huff and Puff in Tight Oil Reservoirs

Conformance Control for Tight Oil Cyclic Gas Injection Using Foam

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