Using the pair-correlation function as a tool to identify the location for shale gas/oil reservoir based on well-log data

Abstract

Shale reservoirs, as an unconventional resource, are becoming an increasingly important exploration, development, and production target in the oil industry. One of the main problems in these reservoirs is the answer to the question of where to drill (the “sweet-spot” location). In other words, one desires to detect the productive portion of the reservoir. This involves finding data criteria that can be used to distinguish between productive and nonproductive portions of a reservoir. As one of these criteria, we have investigated the amplitude of the pair correlation function (PCF) for sonic data, which reflected the contrast in elastic properties between inclusions (oil and gas) and background media. Based on various data from eight different wells, we calculated the amplitudes of the PCF. The obtained results showed that the productive layers were highly correlated, and nonproductive layers had low values of the PCF amplitude. Hence, the results of these calculations showed the potential applications of the PCF of seismic data and its amplitude in the detection of the productive layers. Therefore, we could use this PCF and its amplitude as a tool to predict the location of shale gas or oil reservoirs and to estimate the thickness of productive zones in the well.