Analysis of Production Data Using the Beta-Derivative

摘要

This paper presents a new insight into rate transient analysis using the beta-derivative function (β-derivative). Productionrates and flowing pressures from tight gas and shale gas wells were analyzed using various implementations of the beta-derivative to emphasize different features of the data and, as a result, reveal characteristic information about flow regimesand the extent to which the reservoir has been drained. The beta-derivative was applied to rate, pressure and normalized rate,and the effect of skin on the β-derivative was also investigated. The intent was to determine which format is the most usefulfor diagnosing the dominant flow regimes or the sequence of flow regimes that have occurred while producing from anunconventional hydrocarbon reservoirs (tight gas, shale gas and light tight oil).It was found that the classic signature of the β-derivative is altered by the presence of skin. Also, the derivative based onconstant rate is different from that based on constant pressure. The beta-derivative's diagnostic value was compared to thatof the Bourdet Derivative and the Primary DerivativeThe β-derivative has significant diagnostic value for identifying power-law type of flow regimes (such as wellbore storage,linear flow, bilinear flow, boundary-dominated flow, etc) because it possesses a recognizable unique character for each ofthese flow regimes. For instance, the β-derivative is 0.5 for linear flow, 0.25 for bilinear flow and 1.0 for boundarydominated flow. In addition, since the β-derivative is dimensionless, it can be used to differentiate the performance of wellsproducing from the same field or from different resource plays. The new plotting functions presented in this paper are notintended to replace existing diagnostic functions but can be used in conjunction with them to enhance production dataanalysis.