Abstract:

Based on evaluating the H production rate decline curve, this paper focuses on the curve’s limitations and adjusts it by theory derivation. A new type of production rate decline curve, which accords with the conservation principle, and its decline factor solution are shown in this paper. The H production rate decline curve and adjusted curve are then used to predict the production of a fractured horizontal gas well in the stage of production rate decline. Finally, a match analysis is used between the results of this calculation and numerical simulation. The results show that on the one hand the new decline curve suggested by this paper keeps the merit of the H decline curve of linking smoothly between initial decline period and production-ascending period or stable production period, on the other hand it makes up the defect of the H decline curve of producing large prediction error when the decline time-point 0 cannot be decided precisely. By using this new method, the prediction precision is enhanced, and the application scope is enlarged. This new type of production rate decline curve can be used in practical prediction calculation.

Key words: production rate decline, conservation principle, prediction, numerical simulation, match analysis