The Study on the Influence of Acidification on the Pore and Seepage Field of Carbonate Reservoir
The mineral composition and content distribution of carbonate rocks in QiXia reservoir formation and porosity and permeability parameters at different acidification time are measured by laboratory experiments. The dynamic changes of pore pressure and borehole wall seepage field during acid fracturing process were simulated by software, the results show that acidification has a significant effect on the porosity and permeability characteristics. The porosity increases as a whole and there are differences in permeability changes. During the production process after acid fracturing, pore pressure relief in the borehole wall varies with the different drawdown pressure. The conductivity of crack seepage is significantly higher than that of base rock. The higher the drawdown pressure is, the greater the crack pore pressure relief, and the larger the reduction range and the influence area of the pore pressure around the well will be. The conductivity of acid fracturing crack is higher than that of the reservoir base rock, and the permeability of matrix is weak. The higher the drawdown pressure difference is, the higher the decreasing amplitude of pore pressure around acid fracturing cracks is, the faster the pressure relief speed is, and the larger the influence area is.
KeywordsCarbonate rock Acidification Matrix Fracture Pore Seepage field
- 5.Talbot, M.S., Gdanski, R.D.: Beyond the Damkohler Number: A New Interpretation of Carbonate Wormholing %J Europec/EAGE Conference and Exhibition (2008)Google Scholar
- 6.Lu, Q., Lu, G., Prioul, R., et al.: Impact of Fluid Acidity on the Time-Dependent Initiation of Hydraulic Fractures in Carbonate Rocks. %J Rock Mechanics & Rock Engineering, vol. 51, pp. 3895–3906. 1 Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, PA, USA 2 Schlumberger-Doll Research, Cambridge, MA, USA 3 Schlumberger Dhahran Carbonate Research, Dhahran, Kingdom of Saudi Arabia 4 Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA, USA (2018)Google Scholar
- 7.Liu, X.J., et al.: Study on the influence of acid on borehole wall stability and critical pressure difference in limestone formation. Drill. Prod. Technol., 112–115 (2007)Google Scholar
- 8.Li, Y.M., et al.: Wormhole dissolution pattern study in complicated carbonate rock based on two-scale continuum model and equivalent seepage theory. Nat. Gas Geosci., 121–127 (2016)Google Scholar