白豹—南梁地区长油藏主控因素及富集规律

Main Controlling Factors and Enrichment Mechanism of Chang 4+5 Reservoir in Baibao-Nanliang Area, Ordos Basin

肖正录 路俊刚 廖建波 李勇 陈世加

XIAOZhenglu LUJungang LIAOJianbo LIYong CHENShijia

油气藏地质及开发工程国家重点实验室·西南石油大学, 四川 成都 610500 天然气地质四川省重点实验室, 四川 成都 610500 西南石油大学地球科学与技术学院, 四川 成都 610500 中国石油勘探开发研究院西北分院, 甘肃 兰州 730020

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China Natural Gas Geology Key Laboratory of Sichuan Province, Chengdu, Sichuan 610500, China School of Geoscience and Technology, Southwest Petroleum University, Chengdu, Sichuan 610500, China Northwest Branch, PetroChina Research Institute of Petroleum Exploration & Development, Lanzhou, Gansu 730020, China

鄂尔多斯盆地延长组油藏普遍高产水是油田精细勘探中面临的主要难题之一。以白豹—南梁地区长油藏为研究对象，通过对烃源岩条件、砂体类型、储层特征、裂缝特征及遮挡条件等成藏主控因素的对比分析，探讨了油藏差异富集的规律。研究认为，白豹地区分布于三角洲下平原和前缘主体带前部，砂体类型主要为水下分流河道，砂体厚度大、渗透率高、侧向延伸远。得益于物性较好的大规模连通性砂体，油水分异充分，原油在浮力作用下向构造高部位运移，导致砂体虽有油气显示，但普遍高含水的特征，低幅度构造是此区域有利的勘探目标。南梁地区分布于三角洲前缘末端，以断续河道和河口坝砂体为主，砂体相对孤立、物性较差、岩性变化频繁。孤立砂体的自生圈闭条件好，油气难以侧向运移，富集程度相对较高，垂向运移通道通畅和储层物性较好的砂体，是此区域的有利勘探目标。

The high water production rate of Yanchang Formation reservoirs in Ordos Basin is one of the main problems in the fine exploration of oilfield. The Chang 4+5 Reservoir in the Baibao-Nanliang Area is taken as the research object. Through the comparative analysis of source rock conditions, sand body types, reservoir characteristics, fracture characteristics, and shielding conditions, the enrichment rules of oil reservoirs are discussed. The results show that the Baibao Area is distributed in the lower delta plain and the near source part of delta front, and the sand body type is mainly underwater distributary channel with large thickness, high permeability, and long lateral extension. Due to the large-scale connectivity sand body with good physical properties, the crude oil migrated laterally to the high part of the structure under the action of buoyancy, resulting in the oil-bearing core producing water. Low amplitude structure is a favorable exploration target in this area. Nanliang Area is distributed at the end of the delta front, mainly composed of mouth-bar sand body. The sand body is relatively isolated, the physical properties are relatively poor and the lithology changes frequently. It is difficult for crude oil to migrate laterally due to the good conditions of authigenic traps in isolated sand bodies. Sand bodies with smooth vertical migration channels and good reservoir physical properties are favorable exploration targets in this area.

10.11885/j.issn.1674-5086.2020.08.26.02