In response to the strong ambiguity of well testing curves for horizontal wells in the Bohai Oilfield,and the lack of distinct linear flow in the horizontal sections of some wells,a horizontal well testing model was utilized to analyze the changes in well testing curves under three well placement scenarios:the horizontal section located in the middle of the reservoir,at the top of the reservoir,and diagonally traversing the reservoir.The key research objects were identified as two situations where the horizontal section is situated in the middle and top of the reservoir.On this basis,the impact of different well storage coefficients,skin factors,thickness,permeability,and the ratio of vertical permeability to horizontal permeability(Kv/Kh)on the timing and duration of linear flow in the horizontal section was analyzed.The reasons for"pseudo-linear flow"and"short linear flow"in actual curves were summarized.The study results indicate that when the well storage coefficient is less than 1 m3/MPa,as the well storage coefficient increases,there is little difference in the occurrence time of linear flow under the same well placement,but there are differences between different well placement methods.When the horizontal section is located at the top of the reservoir,the onset of linear flow is delayed by 0.8 to 1 logarithmic cycle.When the thickness is greater than 20 m and the horizontal well is positioned at the top of the reservoir,the test curve exhibits"pseudo-linear flow"caused by the top boundary effect during the early period,and the duration is 1 to 5 hours.The results of practical applications are of great significance for correctly understanding the test curves of horizontal wells,which can be used to guide the design and interpretation of horizontal well tests in the Bohai Oilfield.
horizontal wellwell testinglinear flow in horizontal sectionwell placement methodBohai Oilfield
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