Mechanical behavior of rocks would have substantial implications for different operations from fluid injection and hydraulic fracturing in hydrocarbon reservoirs to underground carbon dioxide storage in the crust of the earth. In all of these operations, restricting the undesired seismicity events and preserving the integrity of formations is a crucial subject that enforces engineers to evaluate the mechanical behaviors of constituent rocks and predict the formation response. Tensile strength is an important factor for maintaining caprock and reservoir formation from induced tensile cracking which can be influenced by the pore fluid. This paper focuses on the tensile strength of carbonate rock, as an important reservoir rock, in the presence of seawater, as a common injection fluid candidate for enhanced oil recovery objectives. For this purpose, twelve dolomite samples from the Asmari-Jahrum Formation outcrop in Fars province, Iran, were prepared for performing tensile tests. Also for a thorough comparison, sample properties, fluid contents, digital image correlation measurements, and a finite element simulation have been investigated. The experimental results showed a noticeable reduction in the tensile strength of dolomite samples in the presence of distilled water and seawater. In comparison with a dry sample though, a reduction of 16% tensile strength for a seawater saturated sample was observed for similar samples. Among the various mechanisms, which are reported in the open literature, the hydration force seems to be the main reason for the tensile strength reduction and this conclusion was examined by measuring the mass of vaporized adsorbed water on the powder of the same dolomite sample. In addition by testing flooded samples, the impact of flow on the tensile strength was examined. For both cases of seawater and distilled water flooding, the samples which were placed in the outlet zone during the flooding showed lower tensile strength. Moreover, simulation results confirmed the similarity of the weakening trend and impact of seawater.

岩石的力学行为对于从油气储层中的流体注入和水力压裂到地壳中的地下二氧化碳存储等不同操作将具有重大影响。在所有这些操作中，限制不希望的地震事件并保持地层的完整性是至关重要的课题，它迫使工程师评估组成岩石的力学行为并预测地层响应。抗张强度是保持由孔隙流体影响的诱导拉伸裂缝引起的盖层和储层形成的重要因素。本文关注碳酸盐岩的抗张强度，碳酸盐岩是海水存在下的重要储层岩石，是提高采油率的常见注入流体。以此目的，准备从伊朗法尔斯省的阿斯马里-贾赫鲁姆地层露头提取的十二个白云岩样品进行拉伸试验。另外，为了进行彻底的比较，还研究了样品特性，流体含量，数字图像相关性测量和有限元模拟。实验结果表明，在蒸馏水和海水存在下，白云石样品的抗张强度明显降低。但是，与干燥样品相比，类似样品的海水饱和样品的拉伸强度降低了16％。在公开文献中报道的各种机制中，水合力似乎是抗拉强度降低的主要原因，并且通过测量同一白云石样品粉末上的汽化吸附水的质量来检验该结论。此外，通过测试溢流样品，还研究了流量对拉伸强度的影响。对于海水和蒸馏水的两种情况，在洪水期间放置在出口区域的样品均显示出较低的拉伸强度。此外，模拟结果证实了海水减弱趋势和影响的相似性。