The role of calcite mineral elastic moduli in carbonate rock physics
The role of calcite mineral elastic moduli in carbonate rock physics
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DOI：
10.1190/tle42040277.1
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发表时间：
2023-04
期刊：
影响因子：
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通讯作者：
S. Payne;T. Duffy
中科院分区：
文献类型：
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作者：
S. Payne;T. Duffy
碳酸盐岩储层的岩石物理模型假定矿物弹性模量是已知变量。对出版物的回顾揭示了方解石的一系列过时和误导性的值。我们提出了一个强大的汇编为未来的调查。随后，我们讨论了方解石弹性模量的岩石物理建模和解释电缆数据的应用，通过一个案例研究数据集从海上加拿大碳酸盐岩储层。该数据集表现出零孔隙度截距和方解石弹性模量值之间的偏移。我们的经验表明，这种现象存在于世界各地碳酸盐岩储层的许多电缆数据集中。我们证明，数据可以调和矿物弹性模量通过解释的微裂纹的形成（定义为裂纹密度为0.06）。了解相对低孔隙度地层中的微裂纹效应对于正确校准孔隙微结构参数和流体替代计算非常重要。在案例研究数据集的结果表明，流体饱和度的变化相对较高的敏感性。可以通过使用从数据导出的有效矿物弹性模量来降低灵敏度。我们证明有效矿物弹性模量作为矿物模量加微裂纹的代表。有效矿物弹性模量被提出作为一个相对简单的方法来约束流体替代计算在低孔隙度地层中存在微裂纹。
Rock-physics models for carbonate reservoirs assume that the mineral elastic moduli are known variables. A review of publications reveals a range of values for calcite that are out of date and misleading. We present a robust compilation for future investigations. We subsequently discuss the application of calcite elastic moduli for rock-physics modeling and interpretation of wireline data through a case study data set from an offshore Canada carbonate reservoir. The data set exhibits an offset between the zero-porosity intercept and the calcite elastic moduli values. Our experience indicates that this phenomenon is present in many wireline data sets from carbonate reservoirs around the world. We demonstrate that the data can be reconciled to the mineral elastic moduli through the interpretation of microcracks in the formation (defined by a crack density of 0.06). Understanding the microcrack effect in relatively low-porosity formations is important for the correct calibration of pore microstructure parameters and for fluid-substitution calculations. Results in the case study data set show a relatively high sensitivity to changes in fluid saturation. The sensitivity can be reduced through the use of effective mineral elastic moduli that are derived from the data. We justify the effective mineral elastic moduli as a representation of the mineral moduli plus microcracks. The effective mineral elastic moduli are proposed as a relatively simple method to constrain the fluid substitution calculations in low-porosity formations where microcracks are present.