Carbonate rocks commonly exhibit multiscale pore networks because of the interplay of depositional, diagenetic, and structural controls. This interplay commonly leads to carbonate reservoirs with complex pore networks that affect our ability to accurately characterize reservoir quality and be predictive about in-place volumes and hydrocarbon recovery. In particular, the preservation of paleocavern systems can present unique challenges when characterizing carbonate reservoirs because of the difficulty in determining how these large pore systems are distributed and to what degree they remain open during burial. Recognizing the processes by which these caves develop provides key insight into predicting their distribution within the subsurface; however, whether or not such caves are capable of remaining open during burial and at depth remains controversial. This study investigates the preservation potential of water-table caves that have developed in near-surface conditions (i.e., eogenetic coastal karst) and have undergone significant burial by constructing geomechanical finite numerical models. Modeling results suggest that when water-table caves are filled with a fluid, such as water, within the shallow phreatic realm, they can remain open past burial depths of 10,000 m. Conversely, if for some reason a cave is unfilled with a fluid and buried, it experiences total collapse at depths of approximately 1000 m. These results suggest that there is a large preservation potential for water-table caves to remain open and intact at depth, resulting in an additional contribution of pore volume for in-place calculations within oil and gas reservoirs that often are overlooked.

中文翻译：

---

深层地下水洞穴的保存：地下数据和数值模拟的观测

由于沉积，成岩作用和构造控制的相互作用，碳酸盐岩通常表现出多尺度的孔隙网络。这种相互作用通常会导致碳酸盐岩储层具有复杂的孔隙网络，从而影响我们准确表征储层质量并预测就地体积和烃采收率的能力。特别是，在确定碳酸盐岩储层的特征时，古洞穴系统的保存可能面临独特的挑战，因为难以确定这些大孔隙系统的分布方式以及在埋藏期间它们保持何种程度的开放。认识这些洞穴的发育过程，可以为预测地下洞穴的分布提供关键见识；然而，这些洞穴是否能够在埋葬期间和深度保持开放仍存在争议。这项研究通过建立地质力学有限数值模型，研究了在近地表条件下发育的地下水洞穴的保存潜力（即，新生海岸带岩溶），并对其进行了深埋。模拟结果表明，当地下水位洞穴在浅水潜水区中充满流体（例如水）时，它们可以保持开放状态，直至埋葬深度10,000 m。相反，如果由于某种原因，一个洞穴没有充满流体而被掩埋，那么它将在大约1000 m的深度处完全塌陷。这些结果表明，地下水位洞穴在深处保持开放和完好无损的潜力很大，