Abstract

It was showed that reservoir diagenetic and reservoir-forming characteristics are of great value for exploration and exploitation of conventional and unconventional reservoirs. Thus understanding on diagenetic evolution has important significance for successful hydrocarbon exploration. In this paper, a process-based model (PBM) was established to give quantitative characterization of diagenesis strength and its corresponding effect on porosity evolution in burial history on identifying of diagenetic sequence. Taking the Paleogene lake sediment sandstone in Bozhong depression as an example, diagenetic sequences as well as occurrence stage of each diagenesis including compaction (MC), cementation (CEM), and dissolution (DIS) were determined by means of thin section, scanning electron microscope, homogenization temperature of fluid inclusion, and then diagenesis type, diagenesis strength and its effect on porosity in burial history were identified based on diagenetic numerical model proposed in this research. The main understandings are as follows: (i) The lithofacies for the Ed₁, Ed₂, Ed₃, and Es₁ in the Paleogene lake sandstone are Q_63.8F_22.2L_14.0, Q_32.0F_38.9L_29.1, Q_28.8F_59.5L_12.5, and Q_47.1F_16.9L_36.0, respectively; (ii) the reservoir of Paleogene in Bozhong sag is mainly in stage IB‒IIB. It was showed that 1600‒2100 m is in the stage IB, while 2000‒3100 m is in the stage IIA1, 3000‒4000 m is in the stage IIA1, and over 4000 m is in IIB; (iii) The diagenesis experienced by these sandstones includes compaction/carbonate cementation-feldspar dissolution/carbonate dissolution/precipitation of quartz cements and kaolin-illitization of kaoline/illite/precipitation of ferrocalcite and ankerite; (iv) The influence of diagenesis on pore development of the sandstone reservoir in the study area was discussed. The effects of diagenesis on pore development were quantitatively described by compaction, cementation and dissolution, and the effects of diagenesis on pore development were analyzed.

中文翻译：

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基于过程的中深层深埋碎屑岩储层孔隙演化模拟

摘要

研究表明，储层的成岩作用和成藏特征对常规和非常规储层的勘探和开发具有重要价值。因此，了解成岩演化对成功油气勘探具有重要意义。本文建立了基于过程的模型（PBM），以定量表征成岩作用强度及其对埋藏历史中孔隙度演化的影响，以识别成岩作用序列。以渤中depression陷古近纪湖沉积砂岩为例，利用薄片，扫描电镜等手段确定了各成岩作用的成岩顺序以及压实作用（MC），胶结作用（CEM）和溶蚀作用（DIS）。流体包裹体的均质温度 然后根据本文提出的成岩数值模型，确定了成岩类型，成岩强度及其对埋藏史中孔隙度的影响。主要理解如下：（i）Ed的岩相古近纪湖砂岩中的₁，Ed ₂，Ed ₃和Es ₁为Q _63.8 F _22.2 L _14.0，Q _32.0 F _38.9 L _29.1，Q _28.8 F _59.5 L _12.5和Q _47.1 F _16.9 L _36.0， 分别; （ii）渤中凹陷古近系储层主要处于IB‒IIB期。结果表明，IB期为1600‒2100 m，IIA1期为2000‒3100 m，IIA1期为3000‒4000 m，IIB期超过4000 m。（iii）这些砂岩经历的成岩作用包括压实/碳酸盐胶结-长石溶解/碳酸盐溶解/石英胶结的沉淀以及高岭土的高岭土/伊利石的沉淀/铁方解石和角铁矿的沉淀；（iv）讨论了成岩作用对研究区砂岩储层孔隙发育的影响。通过压实，胶结和溶解定量描述了成岩作用对孔隙发育的影响，并分析了成岩作用对孔隙发育的影响。