Shale-gas wells need to be hydraulically fracture-stimulated to produce commercial amount of natural gas. Because shale plays have unique attributes, a systematic approach is essential in the quest for sweet spot identification, proper placing of lateral and identification of best completion intervals in order to get better well performance. In this paper we have discussed how lithofacies classification and its 3D modeling have come out to be a very good tool in the Eagle Ford shale to enhance well productivity.
This is an integrated study where production data of several wells, core data of 36 wells and multi-min processed wire line logs of 74 wells are used for lithofacies analysis. Initially lithofacies are identified on core data and then it has been calibrated to multimineral processed logs using Facies analysis tool of PETRA software. The Eagle Ford formation is classified into eight different lithofacies based on three important parameters i.e. mineralogy, TOC and hydrocarbon filled porosity. Then a 3D lithofacies model is constructed in PETREL by following the same logic and using seismic data, well logs, P-impedance volume etc. Multiple data points covering from LaSalle to Dewitt Counties have been incorporated for lithofacies classification. However the 3D lithofacies model is focused to a small portion of Dewitt County because of the availability of essential data set.
Production data of several wells, chemical tracer data, microseismic data and production log are integrated with the lithofacies 3D model to capture the key drivers for well productivity. This analysis can be applied in micro detailing of shale plays in terms of lithofacies variation and will be very much useful to identify the geographical sweet spots and best completion intervals. Last but not the least, this study emphasizes the importance of accurate geo-steering and its impact on well productivity.
