Evaluation of the Low-Pressure, Low-Yield and Stable Production Capacity of Shale Gas Wells

In the middle and later stages of shale gas well production, the pressure output drops rapidly and the liquid carrying capacity is weakened, resulting in liquid accumulation, which seriously affects the production of gas Wells and even stops production. In order to further study the flow pattern of shale gas tubing running on gas well production in Weiyuan area, the updip horizontal well casing, tubing production simulation experiment, wellbore flow pattern change, wellbore pressure drop calculation and critical liquid carrying flow rate are comprehensively utilized. This paper selects the well flow pattern discriminant plate, revises the well pressure drop model and liquid carrying model, and analyzes the oil and casing flow characteristics, well pressure drop model and liquid carrying model according to the characteristic system of Weiyuan area, providing a theoretical basis for the optimization of tubing parameters. The results show that: (1) under the same gas-liquid volume, the inclined section is the most difficult to carry liquid, followed by the vertical section, and the last is the horizontal section; (2) Four kinds of flow patterns suitable for Weiyuan area are optimized, in which D-R model and AIZI model are used for vertical segment, Kaya model is used for inclined segment, and Mandhane model is used for horizontal segment; (3) The new model can accurately reflect the variation trend of liquid holdup with apparent gas and liquid flow rates at different inclination angles. The deviation of measured values is small and stable, and the accuracy is greatly improved, reaching more than 90%. It is considered that the research results have guiding significance for the stable production capacity of shale gas Wells in low pressure and low production stage.