Berea reservoirs in eastern Kentucky are developed in tight siltstone and sandstone. Precision horizontal drilling provides access to thin (<10 ft) stratigraphic traps, and a new shallow oil play has resulted. Bedding, porosity and permeability data, x-ray diffraction mineralogy data, and petrography are examined and compared in five cores to better understand stratigraphic traps and pore types.Upper Berea reservoirs are developed in storm-dominated shelf and upper-slope siltstones and sandstones, whereas lower Berea reservoirs occur in downslope siltstones and sandstones. Variable bedding on broad clinoforms, soft-sediment deformation, and cementation contributes to reservoir heterogeneity. Permeability and porosity vary within individual types of bedding, although hummocky and swaley bedding generally have higher permeability than that of deformed bedding. For permeability >0.1 md, porosity is generally >10%. Cement in Berea samples includes quartz overgrowths, ferroan dolomite, siderite, pyrite, and kaolinite. In addition, these rocks were subject to varying degrees of intergranular compaction, quartz overgrowths, and secondary porosity formation (grain dissolution). In thin section, three pore types were encountered: (1) primary intergranular pores, (2) secondary moldic pores, and (3) microporosity. Intergranular porosity is most common.Mercury capillary injection tests show that moderate-permeability (0.02–0.2 md) Berea has pore size distributions of 1 to less than 0.1 µm, but mostly from 0.5 to 0.6 µm, which are commonly found in gas reservoirs. Higher-permeability samples (1.2–2.0 md) have pore-throat diameter distributions of 2 to >0.1 µm. The highest pore volumes (near 3.25%) have pore diameters of 1–2 µm, which is more characteristic of oil-producing reservoirs.

中文翻译：

---

肯塔基州东部Berea砂岩（至上泥盆纪）的储层地质

肯塔基州东部的Berea水库是在致密粉砂岩和砂岩中发育的。精确的水平钻井提供了通向较薄（<10英尺）地层圈闭的通道，并且产生了新的浅层油层。在五个岩心中检查并比较了层理，孔隙度和渗透率数据，X射线衍射矿物学数据以及岩石学，以更好地了解地层圈闭和孔隙类型。下层储层位于下坡粉砂岩和砂岩中。宽斜斜岩层上的可变层理，软沉积物变形和胶结作用促进了储层的非均质性。渗透性和孔隙率在不同类型的床上用品中有所不同，通常，相比起变形的被褥，山岗和斯莱利的被褥具有更高的渗透率。对于渗透率> 0.1 md，孔隙率通常> 10％。Berea样品中的水泥包括石英过度生长，铁锰白云石，菱铁矿，黄铁矿和高岭石。此外，这些岩石还经历了不同程度的晶间压实，石英过度生长和次生孔隙形成（颗粒溶解）。在薄截面中，遇到了三种孔类型：（1）初级晶间孔，（2）次级霉菌孔和（3）微孔。粒间孔隙是最常见的。汞毛细管注入试验表明，中等渗透率（0.02–0.2 md）Berea的孔径分布范围为1至小于0.1 µm，但大多数为0.5至0.6 µm，这在气藏中很常见。高渗透率样品（1.2–2。0 md）的孔喉直径分布为2到> 0.1 µm。最高的孔隙体积（接近3.25％）的孔隙直径为1-2 µm，这是产油油藏的更多特征。