Study On The Drainage Radius And Productivity Calculation Of Tight And Condensate Gas Reservoir

Fracturing of tight gas well productivity prediction is of great significance for gas reservoir development design and reasonable allocation.Physical simulation experiments show that pressure sensitive effect,threshold pressure gradient and other seepage characteristics are exist,So Darcy's law is no longer applicable.Meanwhile,there are still condensate phenomenon in the tight and condensate gas reservoir.The main work of this paper includes the following aspects.First,using physical simulation derived empirical formula of pressure sensitive effect and threshold pressure gradient.And using the limit of boundary pressure gradient to deduce the calculation formula of gas drainage radius.Secondly,Using the conformal mapping method,the complex seepage problem of fractured wells becomes into one dimensional flow.The productivity calculation formulas of the gas reservoir fractured wells and fractured horizontal well are derived,considering threshold pressure gradient and pressure sensitive effect.In order to compare the post-fracture response,the productivity calculation formulas of vertical well and horizontal well that are not fractured are derived.Then it also tries to use a more simple method to calculate gas condensate reservoirs Productivity.Final,sensitivity analysis was performed.Pressure sensitive effect and threshold pressure would reduce production,while productivity is more sensitive to pressure sensitive effect,especially when in high pressure difference.For hydraulic fracturing horizontal well,longer Horizontal length,more and longer fractures would bring higher production,but with the increasing of these factors,yield increasing is getting smaller,distribution of fracture is dense in the middle and sparse on both ends,helping improving the production.when producing pressure difference is smaller,precipitation velocity of condensate oil is quicker,hampering the flow of gas,reducing productivity.