EAPSI:Reservoir Quality and Distribution of Low-Permeability Sandstones in the Triassic Yanchang Formation and Implications for Hydrocarbon Exploration

EAPSI：三叠系延长组低渗透砂岩储层质量、分布及油气勘探意义

• 批准号: 1515196
• 负责人: Isaac Allred
• 金额: $ 0.51万
• 依托单位: Allred Isaac
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1515196&HistoricalAwards=false
• 关键词: EAPSI; Reservoir; Quality; Distribution; Low

Low-permeability sandstones, or tight sandstones, can become unconventional hydrocarbon reservoirs due to hydraulic fracturing. The Late Triassic (228-208 million years ago) Yanchang Formation in the Ordos Basin is the largest discovered tight sandstone reservoir in China. This research will apply principles of sedimentology and sequence stratigraphy to interpret a subsurface data set to create a paleogeographic reconstruction and reservoir characterization of the Yanchang Formation. This geologic framework will improve the predictability of the distribution of sandstone reservoirs in the basin. The continued evaluation of the Yanchang Formation has great significance for understanding the geologic history of the Ordos Basin and hydrocarbon exploration. This work will be conducted in collaboration with Dr. Bingsong Yu, a noted expert on the sedimentology and stratigraphy of the Ordos Basin, at China University of Geosciences, Beijing.The Yanchang Formation records a variety of terrestrial depositional environments and the tectonic evolution of the Ordos Basin. Extensive semi-deep and deep lacustrine (lake) sediments developed in the central and southern parts of the basin, resulting in mudstone deposition. The sandstones of river mouth sandbars in the north are composed of fine-grained (125-250 µm sand grains), low-permeability (3-5 millidarcy), arkosic (feldspar-rich) sandstones. These sandbar hydrocarbon reservoirs are located close in proximity to lacustrine source rocks. The overlying mudstones formed a regionally extensive seal that trapped hydrocarbons in the low-permeability sandstones. Modeling based on seismic reflection and well log data will result in a sequence stratigraphic framework which will identify time correlative surfaces, the distribution of sand bodies and the interconnectivity of reservoirs. This NSF EAPSI award is funded in collaboration with the Chinese Ministry of Science and Technology.

低渗透砂岩或致密砂岩由于水力压裂可以成为非常规油气藏。鄂尔多斯盆地晚三叠世延长组（距今2.28 - 2.08亿年）是我国已发现的最大致密砂岩储层。本研究将应用沉积学和层序地层学原理解释地下数据集，以建立延长组的古地理重建和储层表征。这一地质格架将提高盆地砂岩储层分布的可预测性。延长组的继续评价对认识鄂尔多斯盆地的地质历史和油气勘探具有重要意义。延长组记录了鄂尔多斯盆地的多种陆相沉积环境和构造演化。延长组是鄂尔多斯盆地沉积学和地层学研究的重要组成部分。盆地中南部广泛发育半深湖、深湖（湖）相沉积，形成泥岩沉积。北部河口砂坝的砂岩由细粒（125-250 µm砂粒）、低渗透（3-5毫达西）、长石砂岩（富含长石）组成。这些砂坝油气藏与湖相烃源岩的位置非常接近。上覆泥岩形成了区域性的大面积封闭，将烃类截留在低渗透砂岩中。基于地震反射和测井数据的建模将产生层序地层格架，该格架将识别时间相关面、砂体分布和储层的互连性。NSF EAPSI奖是与中国科技部合作资助的。