Karst in interbedded carbonates and evaporites has been reported to have important and complex impacts on reservoir. It is significant for exploration and karst geology. Here, we report such a new case from Middle Tri...Karst in interbedded carbonates and evaporites has been reported to have important and complex impacts on reservoir. It is significant for exploration and karst geology. Here, we report such a new case from Middle Triassic Leikoupo Formation of Sichuan Basin, Southwest China. Stratigraphic incompleteness and the occurrence of unconformity provide evidence for the presence of eogenetic karst. Under the impact of this eogenetic karst, residual weathered and solution-collapse breccia, solution pores and silicification and dedolomitization have been observed. Classic stratigraphic zonation of karst is not readily distinguishable, which is ascribed to the stratigraphic collapse of carbonate rocks resulting from the dissolution of evaporites by lateral subsurface fluid flow. In terms of impact on reservoir quality, karst can generally improve the initial physical property of the porous layers in theory. However, subsurface fluid flow dissolved the evarporitic beds and facilitated the collapse of overlying strata. As a consequence, the lateral continuity of the reservoirs would be destroyed, and relatively high-quality reservoirs can only be developed with little collapse of overlying strata, reflecting reservoir heterogeneities. This may be a general feature of reservoir formation under the impact of karst in interbedded carbonates and evaporites.展开更多
基金the National Natural Science Foundation of China(81930124,82021005,81230069,8207355,and 91643202)the Shanghai Municipal Science and Technology Major Project(2017SHZDZX01)+4 种基金the Fundamental Research Funds for the Central Universities(2021GCRC075 and 2021GCRC076)the National Key Research and Development Program of China(2017YFC0907504)Hubei Province Science Fund for Distinguished Young Scholars(2021CFA048)the National Nutrition Science Research Grant(CNS-NNSRG2021-10)the China Postdoctoral Science Foundation(2021M691129).
文摘在糖尿病前期人群中,采取健康的生活方式可以有效预防糖尿病的发生。然而,健康生活方式与心血管疾病(cardiovascular disease,CVD)、癌症和死亡的长期风险之间的关联尚未阐明。本文旨在探究糖尿病前期人群中综合健康生活方式与上述多种健康结局之间的关联。本研究纳入的121254名糖尿病前期参与者来自以下4个前瞻性队列,包括中国的东风-同济队列(Dongfeng-Tongji,DFTJ)和开滦研究,英国生物银行(UK Biobank,UKB)和美国的国家健康与营养调查(National Health and Nutrition Examination Survey,NHANES;仅用于死亡分析)。随访期间,共诊断了18333例新发糖尿病病例、10829例新发心血管疾病病例、6926例新发癌症病例和9877例全因死亡。本文基于5个因素(从不吸烟或戒烟超过10年、适量饮酒、充足的体力活动、健康膳食和理想的腰围)构建综合健康生活方式评分。各因素均被分为健康水平(赋1分)和不健康水平(赋0分),评分的加和为综合健康生活方式评分(0~5分)。首先,采用Cox比例风险回归模型计算每个队列中综合健康生活方式评分与健康结局之间的关联;然后,通过随机效应模型的荟萃分析合并各独立队列结果的多变量校正的风险比(hazard ratio,HR)和95%置信区间(confidence interval,CI)。与生活方式最不健康(评分为0~1分)的研究对象相比,生活方式最健康(评分为4~5分)的研究对象具有更低的糖尿病、心血管疾病、癌症和死亡风险,合并的HR(95%CI)分别为0.57(0.48~0.69)、0.67(0.62~0.73)、0.80(0.73~0.88)和0.54(0.42~0.70)。根据研究对象的基线人口学特征和代谢健康状况进行亚组分析的结果也与主要分析的结果一致。总而言之,本研究对来自三个国家的4个队列的合并分析表明,在糖尿病前期人群中,坚持更健康的生活方式与糖尿病及主要并发症的发生风险降低有关。本研究的发现为临床指南和公共卫生政策提供了可靠证据。
基金funded by the “13th Five-Year Plan” National Science and Technology Major Project of China(No.2016ZX05004002)
文摘Karst in interbedded carbonates and evaporites has been reported to have important and complex impacts on reservoir. It is significant for exploration and karst geology. Here, we report such a new case from Middle Triassic Leikoupo Formation of Sichuan Basin, Southwest China. Stratigraphic incompleteness and the occurrence of unconformity provide evidence for the presence of eogenetic karst. Under the impact of this eogenetic karst, residual weathered and solution-collapse breccia, solution pores and silicification and dedolomitization have been observed. Classic stratigraphic zonation of karst is not readily distinguishable, which is ascribed to the stratigraphic collapse of carbonate rocks resulting from the dissolution of evaporites by lateral subsurface fluid flow. In terms of impact on reservoir quality, karst can generally improve the initial physical property of the porous layers in theory. However, subsurface fluid flow dissolved the evarporitic beds and facilitated the collapse of overlying strata. As a consequence, the lateral continuity of the reservoirs would be destroyed, and relatively high-quality reservoirs can only be developed with little collapse of overlying strata, reflecting reservoir heterogeneities. This may be a general feature of reservoir formation under the impact of karst in interbedded carbonates and evaporites.
