Xinjiang Petroleum Geology ›› 2021, Vol. 42 ›› Issue (2): 179-187.doi: 10.7657/XJPG20210208

• RESERVOIR ENGINEERING • Previous Articles     Next Articles

Establishment and Application of a New Analytical Fractional Flow Equation

GAO Wenjun1(), YIN Rui2, GAO Neng1, SHENG Han3, GAO Zhijiang4   

  1. 1. Research Institute of Exploration and Development, Tuha Oilfield Company, PetroChina, Hami, Xinjiang 839009, China
    2. School of Petroleum Engineering, Yangtze University, Wuhan, Hubei 430100, China
    3. EnerTech-Drilling & Production Co., CNOOC Energy Technology & Services Limited, Tianjin 300452, China
    4. Daqing Branch, China Petroleum Logging Co., Ltd., CNPC, Daqing, Heilongjiang 163412, China
  • Received:2020-02-15 Revised:2020-09-18 Online:2021-04-01 Published:2021-04-02

Abstract:

On the basis of determining the new generalized water flooding characteristic curves, by using reverse reasoning methods, the water flooding characteristic curves can be inverted into the laws of water cut variation, and then combined with the Welge equation, the analytical fractional flow equation when water drives oil can be derived. The new fractional flow equation is a transcendental equation, and under certain conditions, it can be simplified to the results of typical oil-water two-phase seepage experiment. If the new analytical fractional equation is combined with the Levinlet function, the relation of oil-water permeability ratio that characterizes the two-phase seepage characteristics can be obtained. The water-flooding experimental data from 4 different types of reservoirs were used to perform fitting, the results showed that the fitting degree of the new equation was high, and the fitting effects were satisfactory. Furthermore, the laws of water cut variation corresponding to the new equation can not only describe the relationship between convex-shaped recovery degree and water cut, but also can describe the correlation between S-shaped, concave-shaped recovery degree and water cut. Taking the reservoirs in Xishanyao formation of Baka oilfield as an example, the analytical fractional flow equation of actual water displacing oil was given by using production data.

Key words: generalized water flooding characteristic curve, water cut variation law, recovery degree, water cut, fractional flow equation, seepage characteristic, oil-water permeability ratio

CLC Number: