Key factors controlling shale oil enrichment in saline lacustrine rift basin:implications from two shale oil wells in Dongpu Depression,Bohai Bay Basin

Comparative analyses of petroleum generation potential,reservoir volume,frackability,and oil mobility were conducted on 102 shale cores from the Dongpu Depression.Results show the shale has high organic matter contents composed of oil-prone type I and type II kerogens within the oil window.Various types of pores and fractures exist in the shale,with a porosity of up to 14.9%.The shale has high brittle mineral contents,extensive fractures,and high potential for oil mobility due to high seepage capacity and overpressure.Although the petroleum generation potential of the shale at Well PS18-8 is relatively greater than that at Well PS18-1,oil content of the latter is greater due to the greater TOC.The porosity and fracture density observed in Well PS18-1 are greater and more conducive to shale oil enrichment.Although the shales in Wells PS18-1 and PS18-8 have similar brittle mineral contents,the former is more favorable for anthropogenic fracturing due to a higher preexisting fracture density.Besides,the shale at Well PS18-1 has a higher seepage capacity and overpressure and therefore a higher oil mobility.The fracture density and overpressure play key roles in shale oil enrichment.

裂陷盆地构造演化及盆地伸展模式——以东濮凹陷为例

东濮凹陷是我国东部典型的裂陷盆地。盆地的构造演化经历了早古生代至三叠纪的克拉通盆地旋回和新生代的裂陷盆地旋回。新生代裂陷盆地旋回又划分为早期裂陷、强烈裂陷、晚期裂陷和晚第三纪整体坳陷4个阶段。东濮凹陷基底伸展量的变化总趋势是由北向南加大,地壳上部的伸展构造变形为简单剪切伸展模式,而地壳下部具有纯剪切机制。滑脱面变异带可能是造成东濮凹陷内桑村集-桥口-白庙横向构造变换带、南北构造活动差异性以及油气富集程度差异性的重要原因。

裂陷盆地断块群类型——以东濮凹陷为例

断块是重要的油气储集单元,断块群则是断块的有序组合,是油气藏组合体。断块油气藏的勘探迫切需要一个合理的断块群分类方案。文中从几何学—运动学方面出发,讨论了裂陷盆地断块群分类方案,然后结合裂陷盆地结构,讨论了不同构造部位可能出现的断块群类型,也从这个角度初步讨论了断块群的成因。最后,结合东濮凹陷实际,讨论了不同构造部位发育的不同类型断块群的构造特点和含油气性。

陆相断陷咸化湖盆有机质差异富集因素探讨——以东濮凹陷古近系沙三段泥页岩为例

我国中、新生代陆相断陷咸化湖盆广泛发育含盐泥页岩,蕴藏着大量页岩油资源。页岩油“甜点”发育与有机质富集密切相关,但含盐泥页岩有机质差异富集主控因素研究相对较少,且存在争议。以渤海湾盆地东濮凹陷为例,针对古近系沙三段泥页岩取芯,开展总有机碳(TOC)、扫描电镜、能谱分析以及主量、微量和稀土元素分析,探讨泥页岩的有机质丰度与古气候、古盐度、沉积速率、古生产力和氧化还原条件的关系。结果表明:沙三段泥页岩的有机质富集主要受控于古生产力、古盐度和沉积速率。古生产力越大,有机质富集程度越高;随古盐度和沉积速率升高,有机质富集程度先增大后减小。氧化还原条件对有机质富集的影响不大,这与泥页岩整体发育于缺氧的还原条件有关。只有在高的古生产力、适当的古盐度和适当的沉积速率背景下,方才利于沉积有机质富集。泥页岩的有机质差异富集是非常规油气沉积学研究的重要内容之一,揭示有机质差异富集主控因素,对我国陆相页岩油勘探开发具有重要意义。

东濮凹陷半地堑分析

普通意义上的“裂谷”、裂陷盆地实际上大部分是一系列半地堑以不同方式联结而成。本文以半地堑理论为基础，分析了东濮凹陷中半地堑联结的一些实例，进而通过对整个凹陷的半地堑分析，指出本濮凹陷实质上是由30余个半地堑（ES3期）错综复杂联结而成，并通过半地堑分析，揭示了其演化过程。由此，从另一个角度，对东濮凹陷的结构形态产生了新的认识。最后分析了半地堑联结与油气聚集的关系，并指出了东濮凹陷今后的几个勘探方向。此文证明了半地堑理论的实用性与优越性，是盆地分析工作中的一种新思路、新方法。