The study on Lower Cambrian dolostones in Tarim Basin can improve our understanding of ancient and deeply buried carbonate reservoirs. In this research, diagenetic fluid characteristics and their control on porosity evolution have been revealed by studying the petrography and in situ geochemistry of different dolomites. Three types of diagenetic fluids were identified: (1) Replacive dolomites were deviated from shallow burial dolomitizing fluids, which might probably be concentrated ancient seawater at early stage. (2) Fine-to-medium crystalline, planar-e diamond pore-filling dolomites (Fd1) were likely slowly and sufficiently crystallized from deep-circulating crustal hydrothermal fluids during Devonian. (3) Coarse crystalline, non-planar-a saddle pore-filling dolomites (Fd2) might rapidly and insufficiently crystallize from magmatic hydrothermal fluids during Permian. Early dolomitizing fluids did not increase the porosity, but transformed the primary pores to dissolution pores through dolomitization. Deep-circulating crustal hydrothermal fluids significantly increased porosity in the early stages by dissolving and then slightly decreased the porosity in the late stage due to Fd1 precipitation. Magmatic hydrothermal fluids only precipitated the Fd2 dolomites and slightly decreased the porosity. In summary, Devonian deep-circulating crustal hydrothermal fluids dominated the porosity evolution of the Lower Cambrian dolostone reservoir in the Tarim Basin.

中文翻译：

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塔里木盆地西北缘下寒武统肖尔布拉克组白云岩成岩流体的性质，类型，成因及其对孔隙度的控制

对塔里木盆地下寒武统白云岩的研究可以增进我们对古老的深埋碳酸盐岩储层的了解。通过研究不同白云岩的岩石学和原位地球化学，揭示了成岩流体特征及其对孔隙演化的控制。鉴定出三种成岩流体：（1）替代性白云岩与浅埋的白云石化流体不同，后者可能是早期的古海水浓缩。（2）泥盆纪期间，深部地壳热液中的中细晶，平面e金刚石孔隙填充白云岩（Fd1）可能缓慢而充分地结晶。（3）粗结晶，非平面-鞍状孔隙填充白云岩（Fd2）可能在二叠纪期间从岩浆热液中迅速结晶而不足。早期的白云石化流体并未增加孔隙度，而是通过白云石化作用将主要孔隙转化为溶蚀孔隙。深循环地壳热液在早期通过溶解明显增加了孔隙度，然后在后期由于Fd1沉淀而使孔隙度略有降低。岩浆热液仅使Fd2白云岩析出，并略微降低了孔隙度。总之，在塔里木盆地下寒武统白云岩储层的孔隙度演化中，泥盆系深循环地壳热液占主导地位。但通过白云石化作用将初级孔隙转化为溶解孔隙。深层地壳热液在早期通过溶解显着增加了孔隙度，而在后期由于Fd1沉淀而使孔隙度略有降低。岩浆热液仅使Fd2白云岩析出，并略微降低了孔隙度。总之，在塔里木盆地下寒武统白云岩储层的孔隙度演化中，泥盆系深循环地壳热液占主导地位。但通过白云石化作用将初级孔隙转化为溶解孔隙。深循环地壳热液在早期通过溶解明显增加了孔隙度，然后在后期由于Fd1沉淀而使孔隙度略有降低。岩浆热液仅使Fd2白云岩析出，并略微降低了孔隙度。总之，在塔里木盆地下寒武统白云岩储层的孔隙度演化中，泥盆系深循环地壳热液占主导地位。岩浆热液仅使Fd2白云岩析出，并略微降低了孔隙度。总之，在塔里木盆地下寒武统白云岩储层的孔隙度演化中，泥盆系深循环地壳热液占主导地位。岩浆热液仅使Fd2白云岩析出，并略微降低了孔隙度。总之，在塔里木盆地下寒武统白云岩储层的孔隙度演化中，泥盆系深循环地壳热液占主导地位。