Methods of determining commercial oil flow standard in shale reserves estimation: a case study of Permian Lucaogou formation in Jimusar depression

The shale oil is significantly different from conventional reservoirs in reservoir characteristics, development methods and production performance.The conventional method of determining commercial oil flow standard is no longer applicable.On the basis of break-even principle and cash flow method, a standard calculation model of commercial oil flow for shale oil is established combined with the “two-stage” decline producing pattern and the consideration of time value of fund.The standard commercial oil flow index includes the minimum initial stable production, minimum cumulative production and minimum net pay thickness.A standard plate is built according to the standard calculation model of commercial oil flow, drilling investment, costs, oil-gas price and reservoir parameters of shale oil.This standard plate different commercial oil flow will be determined at different oil price and different length of horizontal well section.The plate shows that the minimum initial stable production, minimum cumulative production will be increased along with the increase of the horizontal section, while the minimum net pay thickness decreased.When the oil price is 70 /bbl, and the horizontal section increased from 1 500 m to 2 00 m, the minimum initial stable production and minimum cumulative production will increase from 19.51 t/d and 1.92×10⁴ t to 23.04 t/d and 2.27×10⁴ t, respectively.The minimum net pay thickness decreases from 9.42 m to 8.67 m.