Hydraulically fracturing long horizontal wells is the key technology for economically producing hydrocarbon from unconventional reservoirs. A reservoir's fracability (the ease by which it can be hydraulically fractured) has often been used as an important parameter for identifying the sweet spots for production. Several fracability indicators, based on different types of rock properties, including mechanical, geochemical, and mineralogical properties, have been developed and used in industry. This study, based on observations from a source rock reservoir, proposes the use of reservoir water saturation as a new fracability indicator for organic-rich tight carbonate source rocks that are not clay rich. The results from a machine learning model trained with the observations clearly show the strong and positive correlation between the linear flow parameter (that is obtained based on the newly proposed equivalent-state approximation and characterizes the effectiveness of hydraulic fracturing) and the water saturation for oil wells, but not for gas wells. While further investigation is needed, the results may be due to the dual wettability of the carbonate source rock. Since minerals are more water-wet than the organic matter, reservoir water tends to occupy pore spaces in the mineral matrix. Thus, water saturation reflects the relative portion of mineral matrix pore spaces. Given that the low-clay content mineral matrix contains all the brittle components, the pore-space development in the mineral matrix may have important implications for the fracability in the hydraulic fracturing process.

中文翻译：

---

含水饱和度是否是富含有机质但粘土含量低的致密碳酸盐岩烃源岩储层的压裂性指标？

水力压裂长水平井是非常规油气藏经济生产油气的关键技术。油藏的可压裂性（水力压裂的难易程度）经常被用作确定生产最佳点的重要参数。基于不同类型的岩石特性，包括机械、地球化学和矿物学特性，已经开发并在工业中使用了几种压裂性指标。本研究基于对烃源岩储层的观测，建议使用储层含水饱和度作为不富含粘土的富含有机质致密碳酸盐烃源岩的新压裂性指标。用观察训练的机器学习模型的结果清楚地表明线性流动参数（基于新提出的等效状态近似获得并表征水力压裂的有效性）与油的含水饱和度之间的强正相关井，但不适用于气井。虽然需要进一步调查，但结果可能是由于碳酸盐烃源岩的双重润湿性。由于矿物比有机物更亲水，储层水倾向于占据矿物基质中的孔隙空间。因此，含水饱和度反映了矿物基质孔隙空间的相对比例。鉴于低粘土含量的矿物基质包含所有脆性成分，