Abstract. The Lower Cretaceous Bashijiqike Formation of Kuqa depression is ultra-deeply buried sandstone in fold-and-thrust belts. Few researches link diagenetic processes with structure. To fill this gap, a comprehensive analysis integrating diagenesis with structure pattern, fracture and in situ stress is performed following a structural diagenetic approach. The results show that the pore spaces include residual intergranular pores, intergranular and intragranular dissolution pores, and micro-fractures. The sandstones experienced a high degree of mechanical compaction, and compaction is limited in well-sorted rocks or abundant in rigid quartz grains. The most volumetrically important diagenetic minerals are calcites. The framework grains experienced a varied degree of dissolution, and intergranular and intragranular dissolution pores are formed. Special aims are paid on the dissolution associated with the fracture planes. Most natural fractures are cemented by carbonate cements, which limit fluid flow. In addition, presences of fracture enhance dissolution, and the fracture planes are enlarged by dissolution. Cementation and dissolution can occur simultaneously in fracture surfaces, and the enlarged fracture surfaces can be cemented by late-stage cements. The in situ stress magnitudes are calculated using well logs. The horizontal stress difference (Δσ) determines the degree of mechanical compaction, and rocks associated with low Δσ experienced a low degree of compaction, and there contain preserved intergranular pores. Natural fractures are mainly related to the low Δσ layers. The presences of intergranular and intragranular dissolution pores are mainly associated with the fractured zones. The high quality reservoirs with intergranular pores or fractures are related to low Δσ layers. The structural diagenesis researches above help the prediction of reservoir quality in ultra-deep sandstones, and reduce the uncertainty in deep natural gas exploration in Kuqa depression.

中文翻译：

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塔里木盆地库车坳陷超深层致密砂岩构造成岩作用

摘要。库车坳陷下白垩统巴什吉奇克组为超深埋藏褶皱冲断带砂岩。很少有研究将成岩过程与结构联系起来。为了填补这一空白，按照构造成岩方法进行了将成岩作用与构造模式、裂缝和地应力相结合的综合分析。结果表明，孔隙空间包括残余粒间孔、粒间和粒内溶蚀孔和微裂缝。砂岩经历了高度的机械压实，在分选良好的岩石或富含刚性石英颗粒的情况下，压实作用有限。体积上最重要的成岩矿物是方解石。骨架颗粒经历了不同程度的溶蚀作用，形成了粒间和粒内溶孔。对与断裂面相关的溶解有特殊要求。大多数天然裂缝由碳酸盐胶结物胶结，限制了流体流动。此外，裂缝的存在促进了溶解，并且断裂面因溶解而扩大。裂缝面胶结和溶解可同时发生，扩大的裂缝面可被后期胶结物胶结。使用测井数据计算地应力大小。水平应力差（Δσ）决定了机械压实程度，与低Δσ相关的岩石经历了低程度的压实，并含有保留的粒间孔隙。天然裂缝主要与低Δσ层有关。粒间和粒内溶孔的存在主要与裂缝带有关。具有粒间孔或裂缝的优质储层与低Δσ层有关。上述构造成岩作用研究有助于预测超深层砂岩储层质量，降低库车坳陷深层天然气勘探的不确定性。