Abstract: The shale oil reservoirs in Qingcheng oilfield, located in Ordos Basin, are characterized by multiple periods of vertically stacked oil layers and strong lateral heterogeneity, making it challenging to optimize the development well pattern. Based on considering the geological characteristics of shale oil reservoirs in Qingcheng oilfield, and comprehensively using the methods of oilfield application, reservoir engineering and numerical simulation, a systematic study was conducted on the orientation, length, well spacing, three-dimensional well pattern development, and reasonable stratification of the horizontal section, so as to maximize the utilization of reserves. The results show that the main orientation of horizontal wells should be perpendicular to the maximum principal stress direction; however, taking into account the distribution direction of sand bodies, the utilization of underground reserves, and the location of surface well site, the orientation of wells in horizontal section can be appropriately deviated in the target front area and restricted surface area. The optimal length of horizontal section is mainly 1 500 m, and the length of the horizontal section affected by the extension of sand body is within the range of 600 m to 800 m. The optimized controllable reserves per well is (25-30)×10⁴ t, and generally the well spacing is 500 m; there are various deployment areas in the oil layers of different thickness. The three-dimensional development technique is applied for the oil layers with a vertically stratified thickness greater than 10 m. Based on the above study, a three-dimensional well pattern has been established for the multi-layered shale oil reservoirs. The research results present a single well estimated ultimate recovery (EUR) of (2.6-2.8)×10⁴ t and an annual oil production of 165×10⁴ t in Qingcheng oilfield, achieving large-scale efficient development.

Key words: Ordos Basin, Qingcheng oilfield, shale oil, development well pattern, optimization technique, application

摘要： 鄂尔多斯盆地庆城页岩油纵向油层多期叠置,横向非均质性强、变化快,开发井网优化难度大。针对庆城页岩油地质特征,为实现储量动用程度最大化,综合利用矿场实践、油藏工程和数值模拟等方法对水平段方位、长度、井距和立体开发井网合理隔层开展了系统研究。研究结果表明:水平井的方位主体采用与最大主应力方向垂直的方案,但在靶前区、地面受限区要综合考虑砂体展布方向、地下储量动用程度和地面井场位置,水平段布井方位可以适当偏转;优化水平段长度主体为1 500 m,受砂体延伸长度短影响的水平段长度为600~800 m;优化单井控制储量为(25~30)×10⁴t,主体井距为500 m,不同油层厚度部署区有所差异;纵向上隔层厚度大于10 m的油层段开展立体开发。基于以上研究,形成了页岩油多层系立体式布井模式。研究成果支撑庆城油田页岩油单井EUR达到(2.6~2.8)×10⁴t,产油量达到165×10⁴t/a,实现了规模效益开发。

关键词: 鄂尔多斯盆地, 庆城油田, 页岩油, 开发井网, 优化技术, 实践