Performance of a tight reservoir horizontal well induced by gas huff–n–puff integrating fracture geometry, rock stress-sensitivity and molecular diffusion: A case study using CO2, N2 and produced gas

Lele Wang, Bing Wei, Junyu You, Wanfen Pu, Jinyu Tang, Jun Lu

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

This work provides a comprehensive workflow with practical guidelines for integrating fracture-geometry, rock stress-sensitivity, and gas molecular diffusion to evaluate the performance of a tight reservoir horizontal well induced by gas Huff–n–Puff (HnP). The laboratory measurements and field results were integrated in numerical simulation. The stress-sensitivity led the permeabilities of the matrix and fractures to significantly decrease during primary depletion and HnP stages, thereby impairing well productivity. Rigorous characterizations of fracture-geometry and rock stress-sensitivity are crucial for history-matching and oil recovery simulation. During produced gas HnP, the cumulative oil production was reduced by 4.6% original oil in place (OOIP) because of the stress-dependent permeability. The hysteresis in fracture-permeability noticeably decreased the transport of mass and pressure but hardly affected the short-term production owing to the rapid closure of fractures during puff stage. The final oil recoveries induced by gas diffusion were 0.4%, 0.04% and 0.35% OOIP by CO2, N2 and produced gas HnP, respectively. The produced gas HnP process produced the highest efficiency of enhanced oil recovery than CO2 and N2 owing to its significant pressurizing effect and lower gas-oil ratio. Minimum-miscibility-pressure should not be the primary consideration for gas HnP in tight reservoirs.

Original languageEnglish
Article number125696
JournalEnergy
Volume263
DOIs
Publication statusPublished - Jan 15 2023

Keywords

  • Fracture-geometry
  • Gas huff–n–puff
  • Gas molecular diffusion
  • Horizontal well performance
  • Rock stress-sensitivity
  • Unconventional resources

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Modelling and Simulation
  • Renewable Energy, Sustainability and the Environment
  • Building and Construction
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Pollution
  • Mechanical Engineering
  • General Energy
  • Management, Monitoring, Policy and Law
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering

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