Various methods are available for calculating the TOC of shale reservoirs with logging data, and each method has its unique applicability andaccuracy. So it is especially important to establish a regional experimental...Various methods are available for calculating the TOC of shale reservoirs with logging data, and each method has its unique applicability andaccuracy. So it is especially important to establish a regional experimental calculation model based on a thorough analysis of their applicability.With the Upper Ordovician Wufeng Fm-Lower Silurian Longmaxi Fm shale reservoirs as an example, TOC calculation models were built by useof the improved DlgR, bulk density, natural gamma spectroscopy, multi-fitting and volume model methods respectively, considering the previousresearch results and the geologic features of the area. These models were compared based on the core data. Finally, the bulk density method wasselected as the regional experimental calculation model. Field practices demonstrated that the improved DlgR and natural gamma spectroscopymethods are poor in accuracy;although the multi-fitting method and bulk density method have relatively high accuracy, the bulk density methodis simpler and wider in application. For further verifying its applicability, the bulk density method was applied to calculate the TOC of shalereservoirs in several key wells in the Jiaoshiba shale gas field, Sichuan Basin, and the calculation accuracy was clarified with the measured dataof core samples, showing that the coincidence rate of logging-based TOC calculation is up to 90.5%-91.0%.展开更多
基金National Key Science&Technology Project“Shale Gas Resource Evaluation and Regional Selection in Upper Yangtze and Dian(Yunnan)-Qian(Guizhou)-Gui(Guangxi)”(No.14B12XQ151001).
文摘Various methods are available for calculating the TOC of shale reservoirs with logging data, and each method has its unique applicability andaccuracy. So it is especially important to establish a regional experimental calculation model based on a thorough analysis of their applicability.With the Upper Ordovician Wufeng Fm-Lower Silurian Longmaxi Fm shale reservoirs as an example, TOC calculation models were built by useof the improved DlgR, bulk density, natural gamma spectroscopy, multi-fitting and volume model methods respectively, considering the previousresearch results and the geologic features of the area. These models were compared based on the core data. Finally, the bulk density method wasselected as the regional experimental calculation model. Field practices demonstrated that the improved DlgR and natural gamma spectroscopymethods are poor in accuracy;although the multi-fitting method and bulk density method have relatively high accuracy, the bulk density methodis simpler and wider in application. For further verifying its applicability, the bulk density method was applied to calculate the TOC of shalereservoirs in several key wells in the Jiaoshiba shale gas field, Sichuan Basin, and the calculation accuracy was clarified with the measured dataof core samples, showing that the coincidence rate of logging-based TOC calculation is up to 90.5%-91.0%.
