This study investigates the importance of multiple organic–inorganic interactions on heterogeneous carbonate cementation patterns in Silurian deeply buried sandstones, central Tarim Basin, north‐western China, to evaluate their effects on reservoir quality. Petrographic observations and mineral geochemistry identify two stages of carbonate cementation: (i) eogenetic, poikilotopic blocky calcite precipitated at 20 to 50°C (δ¹³C_VPDB from −0.3‰ to +6.8‰; δ¹⁸O_VPDB between −6.6‰ and −2.9‰) and dolomite precipitated at 40 to 62°C (δ¹³C_VPDB from +1.9‰ to +5.3‰; δ¹⁸O_VPDB between −6.2‰ and −2.1‰); and (ii) mesogenetic, isolated pore‐filling ankerite formed at 70 to 120°C (δ¹³C_VPDB from −14.4‰ to −6.6‰; δ¹⁸O_VPDB between −11.6‰ and −7.8‰). The eogenetic carbonates are predominantly distributed as carbonate‐cemented beds or concretions along sandstone–mudstone contacts and were derived mainly from microbial methanogenesis of organic matter and dissolution of carbonate minerals in adjacent calcareous mudstones. The mesogenetic ankerite cements occur predominantly as carbonate‐cemented beds, concretions and patches, and are more concentrated in the central sections of sandstone bodies. It is inferred that ankerite cements were sourced from dissolution of eogenetic calcite and dolomite via in situ generation of organic CO₂ related to thermal decarboxylation of organic acids within sandstones. Kinetic modelling results coupled with petrographic observations illustrate that mesogenetic dissolution of eogenetic calcite and dolomite cements did not enhance total reservoir porosity due to re‐precipitation of ankerite cements on a very local scale within sandstone bodies. The development of extensively carbonate‐cemented geometries (beds, concretions and patches) created by different generations of carbonate cements derived from external sources, led to reservoir heterogeneity and significant destruction of sandstone reservoir quality especially during diagenesis. The results of this study demonstrate the importance of multi‐stage, intra‐formational mass transfer induced by concentration gradients during organic–inorganic interactions in mediating a variety of spatial patterns of carbonate cementation under different diagenetic regimes. Better insights of these organic–inorganic interactions in a coupled sandstone–mudstone system could improve predictive models of heterogeneous diagenetic alterations in deeply buried sandstones of similar origin.

中文翻译：

---

多种有机-无机相互作用及其对非均质碳酸盐胶结模式的影响：以塔里木盆地中部志留系深埋砂岩为例

本研究调查了西北地区塔里木盆地志留系深埋砂岩中多种有机-无机相互作用对非均质碳酸盐胶结模式的重要性，以评估其对储层质量的影响。岩相学观察和矿物地球化学识别碳酸盐胶结的两个阶段：（ⅰ）eogenetic，poikilotopic块状方解石沉淀，在20〜50℃（δ ¹³ C ^ _VPDB从-0.3‰〜+ 6.8‰;δ ¹⁸ ö _VPDB之间-6.6‰和-2.9‰），并在40至62℃（δ白云石沉淀¹³ ç _VPDB从+ 1.9‰至+ 5.3‰;δ ¹⁸ ö _VPDB在-6.2‰和-2.1‰之间）; 和（ii）mesogenetic，分离孔隙填充铁白云石形成在70〜120℃（δ ¹³ C ^ _VPDB从-14.4‰至-6.6‰;δ ¹⁸ ö _VPDB之间-11.6‰和-7.8‰）。生成碳酸盐主要分布在沿砂岩与泥岩接触的碳酸盐胶结层或凝结物中，主要来源于微生物对有机物的甲烷化作用以及碳酸盐矿物在相邻钙质泥岩中的溶解。介晶的钙长石胶结物主要以碳酸盐胶结床，混凝土和斑块的形式存在，并且更集中在砂岩体的中部。可以推论出，生成的方解石和白云石是通过溶解溶蚀而获得的。原位产生有机CO ₂与砂岩中有机酸的热脱羧有关。动力学建模结果和岩相学观察结果表明，由于砂岩体内非常局部的规模上的铁素体胶结物再沉淀，因此生成的方解石和白云石胶结剂的中成因溶解并不能提高总储层的孔隙度。来自外部资源的不同世代碳酸盐胶结物产生的广泛的碳酸盐胶结几何形状（床，混凝土和斑块）的发展，导致了储层非均质性和砂岩储层质量的重大破坏，特别是在成岩作用期间。这项研究的结果证明了多阶段，在不同成岩机制下，有机-无机相互作用过程中浓度梯度引起的构造内质量传递，介导了各种碳酸盐胶结作用的空间模式。在耦合的砂岩-泥岩系统中更好地了解这些有机-无机相互作用可以改善相似成因的深埋砂岩中非均质成岩作用变化的预测模型。