Solid reservoir bitumen is a geologic risk that controls reservoir quality and fluid distribution and has a profound impact on field development and near-field exploration. Understanding the exact mechanism responsible for the development of solid bitumen is therefore a prerequisite toward its proper quantification and mapping. A sandstone reservoir of an anticlinal gas condensate field was investigated geochemically, and data integrated with reservoir diagenetic history to explain abundant solid bitumen encountered within several meters immediately below a regional unconformity in crestal wells, as opposed to deeper sections and downdip wells. The reservoir is generally characterized by a similar sedimentological and diagenetic history across the field, with diagenetic illite grain coats and quartz cement occurring in both updip and downdip wells. The influx of gas condensates into the upper part of the preexisting oil reservoir, possibly facilitated by a major fault, appears to have caused thermodynamic disequilibrium, leading to de-asphalting and subsequent deposition of solid bitumen. Textural and radiometric age dating, integrated with fluid inclusion homogenization temperatures and basin modeling, suggests the initiation of bitumen deposition 129 Ma, immediately after the arrival of gas condensates into the reservoir. As the process was restricted to the uppermost part of the reservoir, it is possible that the solid bitumen, once developed, has improved sealing efficiency along the unconformity and the trapping of subsequent hydrocarbon charges in the underlying reservoir. Better reservoir quality can be inferred farther downdip in areas inaccessible to gas incursions and hence not affected by gas de-asphalting. Other processes, such as regional uplift-induced phase separation, in-reservoir thermal cracking, water-washing, and biodegradation, were also examined and found irrelevant to the formation of solid bitumen in question.

固体储层沥青是一种地质风险，它控制着储层质量和流体分布，并对油田开发和近场勘探产生深远影响。因此，了解导致固体沥青形成的确切机理是对其进行正确定量和定位的先决条件。对背斜凝析气田的砂岩储层进行了地球化学研究，并将数据与储层成岩史相结合，解释了在地壳井区域不整合以下的几米内遇到的大量固态沥青，这与较深的断层井和下倾井相反。该油藏的特征通常是整个油田具有相似的沉积学和成岩史，上倾井和下倾井都存在成岩伊利石颗粒层和石英胶结物。气体凝结物涌入预先存在的油藏的上部，这可能是由于主要断层的促成，似乎引起了热力学不平衡，导致沥青的脱沥青和固体沥青的随后沉积。结合流体包裹体均质温度和盆地建模的质地和放射性年龄测年表明，在天然气凝析气进入储层后立即开始了129 Ma的沥青沉积。由于该过程仅限于储层的最上部，固体沥青一旦形成，就有可能随着不整合和随后的碳氢化合物在下面的储层中的捕集而提高了密封效率。可以推断出更好的储层质量可以在无法侵入天然气的地区进一步下倾，因此不受天然气脱沥青的影响。还检查了其他过程，例如区域隆起引起的相分离，储层内部热裂解，水洗和生物降解，发现这些过程与所讨论的固体沥青的形成无关。