源储接触关系及其对近源致密油富集的影响——以鄂尔多斯盆地陇东地区长8油藏为例

Influence of source-reservoir contact conditions on the enrichment of near-source tight oil: taking Chang 8 reservoir in the Longdong area of Ordos Basin as an example

肖正录 李勇 朱志勇 路俊刚 卢子兴 李程善

XIAO Zhenglu LI Yong ZHU Zhiyong LU Jungang LU Zixing LI Chengshan

油气藏地质及开发工程国家重点实验室(西南石油大学), 成都 610500 天然气地质四川省重点实验室(西南石油大学), 成都 610500 西南石油大学 地球科学与技术学院, 成都 610500 中石油物资股份有限公司 西安分公司, 西安 710000 长庆油田 勘探开发研究院, 西安 710000

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, Southwest Petroleum University, Chengdu, Sichuan 610500, China School of Geosciences and Technology, Southwest Petroleum University, Chengdu, Sichuan 610500, China Xi'an Branch of PetroChina Materials Co., Ltd., Xi'an, Shaanxi 710000, China Research Institute of Exploration and Development, Changqing Oilfield Company, Xi'an, Shaanxi 710000, China

对致密油地质特征的认识已经相对成熟，但对致密油分布规律的认识还有许多急需回答的问题。通过岩心、测井、物性等资料的综合分析，并借助均质储层原油充注动力的理想化模型，研究了源储接触关系对鄂尔多斯盆地陇东地区长81段近源致密油富集的影响。根据实际地质条件, 可将源储接触关系细分为直接接触型、过渡接触型、泥质隔挡型和裂缝沟通型四种类型。其中，直接接触型和裂缝沟通型对致密油的运聚有利，而过渡接触型和泥质隔挡型对致密油的运移具有明显的阻挡作用。陇东地区长81段致密储层中的油井大多分布于源储间泥质岩层厚度小于4 m的区域内，而水井和干井大多分布于源储间泥质岩层厚度大于4 m的区域内。源储接触关系决定了原油在近源致密储层中的富集程度，在对诸如鄂尔多斯盆地延长组长81段近源致密油的勘探过程中，不但要寻找利于原油侧向运移的储层“甜点区”，还需重点考虑源储接触关系类型对致密油成藏的影响。

The geological characteristics of tight oil have been relatively well understood, but there are certain questions needed to be answered regarding the distribution of tight oil. With comprehensive analysis of core, well logging and physical properties, and by means of mathematical calculation, the effects of the source-reservoir contact conditions on the enrichment of near-source tight reservoir of the first section of the eighth member of Yanchang Formation (Chang 81) in the Longdong area of Ordos Basin were studied in this paper. Results show that the source-reservoir contact conditions can be classified as four types including direct contact, transitional contact, fracture connected, and mudstone barrier. Among them, the direct contact and fracture connected types are favorable for the migration and accumulation of tight oil, while the transitional contact and mudstone barrier types have an obvious barrier effect for the migration of tight oil. The oil wells in the Chang 81 member in the Longdong area are mainly located in regions with a thickness of mudstone barrier less than 4 m, while the water or dry wells are mainly located in regions with a mudstone barrier thickness greater than 4 m. Based on the above calculation, it can be concluded that the source-reservoir contact condition determines the enrichment and vertical migration distance of tight oil. For the exploration of near-source tight oil, not only the "sweet zone" of the reservoir is conducive, the type of the source-reservoir contact condition should also be considered as a key factor.

国家自然科学基金 41872165;国家自然科学基金 42002176

https://doi.org/10.11781/sysydz202205825