Abstract: In recent years, the technology for horizontal drilling is developing rapidly. Featured by large drainage area, low production pressure, high productivity and broad applicability, the horizontal well has much more unique superiority than vertical well. One of reasons for horizontal well not being popularized extensively is the lag in its production prediction. According to near 200 horizontal well's production data at home, the production decline laws for 8 kinds of reservoirs by horizontal well, such as bottom water, super heavy oil, low permeability and thin bed reservoirs, are presented, with corresponding production formulas and the cumulative production formulas. By using the initial productivity equation and the production decline empirical equation, the future production of a horizontal well could be exactly predicted at designing step of horizontal drilling.

Key words: horizontal well, horizontal drilling, productivity, prediction, formula, equation