Art Of Modern Productivity Analysis For Oil & Gas Wells

The validity of development program is greatly affected by potential analysis, especiallywith regard to oil pumping,behavoir analysis and improvement of economic benefit in oil&gasexploration and development.Firstly, rate decline analysis with common vertical wells is made. The relationships ofplan linear and radial flow under transient state is developed and approximation of radial flowunder late pseodsteady state is made to give a new set of plotting variables to establishFetkovich type curves based on Fetkovich's origin idea and make the dimensionless ratesunitary in late pseodsteady stage. The new plotting method provided in this article is muchsimpler. In the research Laplace Transformation and Stehfest Numerical Inversion are used togive the final dimensionless rates, and dimensionless rates vs dimensionless time is plotted toobtain some direct analysis results: the rates in early and middle stages are encompassed bylinear flow and radial flow in pseodsteady state, and become unitary to exponential decline inlate stage. Rates in linear flow have the largest initial value, but it drops quickly. And the largerthe value of reD, the faster it gets close to exponential decline while the smaller the value ofreD, the faster it gets close to linear flow. The dimensionless accumulative rates finally becomeunitary at the largest value point, which indicates that for a given reservoir the final recovery isthe same despite stimulation which only accelerates the recovery speed.Secondly, the method used in Chapter 1 are introduced to vertical wells with one piece ofinfinite conductivity fracture. Taking advantage of the idea of point-linear source and Duhamelsuperposition, relationships of radial flow under transient state are developed andapproximation is achieved for late stage. Similar to the previous disposal, type curves areplotted and decline analyses are made.Finally, the application of material balance in gas reservoir is discussed. Bottomholepressure relationships for oil radial flow are compared with gas relationships and in terms ofBlasingame's rate transformation theory modified time in material balance for gas well is givenout and calculated with real production data.In the processing of vertical wells and fractured wells, the traditional Arps decline typecurves are certified to have scientific basis and only good for rate decline analysis in late stage.