Romania has a long history of hydrocarbon production and tens of thousands of boreholes have penetrated Miocene strata. Many well cores or cuttings have been either lost or damaged, but lab reports containing valuable petrographic, paleontological and structural data are still available. Most of the knowledge of the subsurface relies on old descriptions and interpretations used by the oil industry. These data have not been recently updated, while research results from the last decade suggest potential changes in stratigraphy, especially for the lower to middle Miocene succession. In order to update, calibrate, and reduce uncertainties regarding the subsurface stratigraphic record, we have reviewed the lab reports and used equivalent field samples for an updated interpretation of the lower to middle Miocene succession. Core and cutting descriptions from boreholes covering an area of ~10,000 km2 in the Diapir Fold Zone of the Eastern Carpathians have been selected and biostratigraphically re-evaluated based on microfossils and calcareous nannofossils. In many cases, highly uncertain ages were previously interpreted as Oligocene and early Miocene. Our recent data suggest that most of the lower Miocene is either difficult to determine or has been reinterpreted as middle Miocene (e.g., Cornu and Doftana formations). This significant change in ages requires an updated model for the timing of regional structural evolution and may open new exploration opportunities in this highly mature hydrocarbon area. This study demonstrates the need for a new complete and reliable stratigraphic framework for the whole Miocene stratigraphic record of the Eastern Carpathians.

中文翻译：

---

东喀尔巴阡山脉中中新世序列的生物地层学再评价：与罗马尼亚底辟褶皱带油田相关的案例研究

罗马尼亚有着悠久的油气生产历史，数以万计的钻孔已穿透中新世地层。许多井芯或岩屑已丢失或损坏，但仍可获取包含有价值的岩相学、古生物学和结构数据的实验室报告。大多数地下知识都依赖于石油工业使用的旧描述和解释。这些数据最近没有更新，而过去十年的研究结果表明地层可能发生变化，尤其是中新世中下层序列。为了更新、校准和减少地下地层记录的不确定性，我们审查了实验室报告并使用等效的现场样本对中新世中下层序列进行了更新解释。已经选择了覆盖东喀尔巴阡山脉底辟褶皱带约 10,000 平方公里区域的钻孔的岩心和岩屑描述，并根据微化石和钙质纳米化石重新评估了生物地层学。在许多情况下，高度不确定的年龄以前被解释为渐新世和早中新世。我们最近的数据表明，下中新世的大部分要么难以确定，要么已被重新解释为中中新世（例如，Cornu 和 Doftana 地层）。这种显着的年龄变化需要更新的区域结构演化时间模型，并可能在这个高度成熟的油气区开辟新的勘探机会。这项研究表明，东喀尔巴阡山脉的整个中新世地层记录需要一个新的完整可靠的地层框架。