A model for nitrogen injection in horizontal wells of tight oil reservoirs

Gao, Jiaxi; Yao, Yuedong; Liu, Zheng; Jin-xin, Wang

doi:10.1080/15567036.2021.1903622

Cited by 1 publication

(1 citation statement)

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“…Tight oil reservoir is a trendy topic for exploration and development as a typical unconventional petroleum resource (Zhou et al 2021;Zhu et al 2019;Annual Energy Outlook 2020;Ali et al 2020). The technically recoverable resources of tight oil in China are predicted to be about (20-25) × 10 8 t, which is an important replacement resource (Song et al 2020a;Qin et al 2021;Gao et al 2021). Tight oil is light in quality and contains dissolved gas.…”

Section: Introductionmentioning

confidence: 99%

Influence of reservoir lithology on porous flow resistance of gas-bearing tight oil reservoirs and production forecast

Rao

Yang

Zhang

et al. 2021

J Petrol Explor Prod Technol

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The release of dissolved gas during the development of gas-bearing tight oil reservoirs has a great influence on the effect of development. In this article, the high-pressure mercury intrusion experiment was carried out in cores from different regions and lithologies of the Ordos Basin and the Sichuan Basin. The objectives are to study the microscopic characteristics of the porous throat structure of these reservoirs and to analyze the porous flow resistance laws of different lithology by conducting a resistance gradient test experiment. A mathematical model is established and the oil production index is corrected according to the experiment results to predict the oil production. The experimental results show that for tight reservoirs in the same area and lithology, the lower the permeability under the same back pressure, the greater the resistance gradient. And for sandstone reservoirs in different areas, the resistance gradients have little difference and the changes in the resistance coefficients are similar. However, limestone under the same conditions supports a much higher resistance gradient than sandstone reservoirs. Furthermore, the experimental results are consistent with the theoretical analysis indicating that the PVT (pressure–volume-temperature) characteristics in the nanoscale pores are different from those measured in the high-temperature, high-pressure sampler. Only when the pressure is less than a certain value of the bubble point pressure, the dissolved gas will begin to separate and generate resistance. This pressure is lower than the bubble point pressure measured in the high-temperature and pressure sampler. The calculation results show that the heterogeneity of limestone reservoirs and the mismatch of fluid storage and flow space will make the resistance, generated by the separation of dissolved gas, have a greater impact on oil production.

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Section: Introductionmentioning

confidence: 99%