Research On Decrease Rule Of Gas Well In Deep Volcanic Gas Reservoir Of Xushen Oilfield

With the additional development of deep volcanic gas reservoir ,it's urgently to take the study of gas well(production,pressure) decline rule of deep gas resercoir . The normal study method of decline rule is utilizing the actual productive data to define the decline parameters , which is log-log graph decline rule mostly. Predecessors have submitted many methods to define the decline parameters through utilizing the actual productive data, including mainly the H.C.Slider's curve offsetting method ,C.U.IKOKU's try and error method , J.M.Campbell's type curve matching method ,bivariateregression analysis , interpolation method , iteration method , nonproportionality matching method , duplex cut-and-try method , series expansion method , straight-line analysis method , filter after statistics and analysis method etc.The major study method of decline rule used in this article is presented by J.J.Arps , which define the (production,pressure) decline type and initial decline rate of gas well and then define the gas field's decline rule by means of the development state and character of deep pebbly sandstone and volcanic rock , the alternation relation between production and time , cumulative production and time , instantaneous production and time. By means of the decline rules , take the gas field's dynamic analysis and production prediction .The final computational solution divide the production tendency of wells in research zone into four types , they are depletion decline , exponential decline , hyperbolic decline and a kind of model of Wengcycle of which gas well production is in the rising stage or stabilized production stage . The concrete result is 3 wells of 15 wells will be in the stabilized production stage or go into the decline stage if they continue to product with the old productive pattern , the 3 wells can only calculate with Wengcycle model . And the other 12 wells which producted with the current productive pattern have be in the decline stage , the one is hyperbolic decline , the 5 is depletion decline and the 6 is exponential decline .In the process of caculating with decline model , the relations of every well among production time,production and cumulative production are not permanent , but they are dynamic alternation with the production process .