摘要： 砾岩油藏在我国储量超过20亿t,是我国油气能源的重要接替领域之一.但是,砾岩储层含有大量砾石,具有力学特征非均质性强、裂缝扩展路径差异大的特点,压裂施工中实现均衡布缝的难度大,用现有均匀岩石裂缝扩展理论难以有效解释,需要探索适用于砾岩的相关理论与方法.针对砾岩储层特征和开发工程困境,本文从岩石特征、研究方法、力学性质、裂缝扩展规律与水力压裂技术对策 5个方面,探讨了砾岩开发中的难题与对策.据此,提出了综合细观尺度、常规尺度、大物模尺度、米级尺度、矿场尺度的多尺度分析方法,并通过尺度升级将室内研究结果应用于油田现场的思路;厘清了砾石、杂基以及胶结面是控制岩石力学参数与破裂规律的关键,需建立弱胶结面模型来提高力学参数预测精度;明确了砾岩裂缝扩展有穿砾和绕砾两种模式,存在明显的过程区特征,可参考双K断裂准则构建适用于砾岩的裂缝扩展模型,预测起裂与扩展参数;可压性评价要以地质工程一体化为指导思想,综合岩石组构特征与多尺度力学参数来建立,筛选储层并优化压裂施工方案.

关键词: 砾岩, 地质工程一体化, 多尺度, 水力压裂, 可压性

Abstract: Conglomerate oil reservoirs have reserves exceeding 2 billion tonnes in China and are one of the important replacement fields for oil and gas energy in China.However,conglomerate reservoirs contain a large amount of gravel,which is very heterogeneous mechanically and has significant differences in crack propagation paths.It is difficult to achieve balanced distribution of fractures in fracturing,and it is difficult to effectively explain using existing theories of uniform rock crack propagation.Therefore,it is necessary to explore relevant theories and methods applicable to conglomerate.In response to the characteristics of conglomerate reservoirs and the difficulties in development engineering,this article explores the difficulties and countermeasures in conglomerate development from five aspects:rock characteristics,research methods,mechanical character-istics,fracture propagation and hydraulic fracturing technology.Based on this,a multi-scale analysis method was proposed for comprehensive mesoscale,conventional scale,large scale model,meter scale,and field scale,and the laboratory research results were applied to oilfield sites through scale upgrading;Clarifying the gravel,mixed base,and cementation surface is the key to controlling rock mechanical parameters and fracture patterns.It is necessary to establish a weak cementation surface model to improve the accuracy of mechanical parameter prediction;It has been clarified that there are two modes of conglomerate fracture propagation:through gravel and around gravel,with obvious process zone characteristics.A fracture propagation model suitable for conglomerate can be constructed based on the double K fracture criterion to predict the initiation and propagation parameters;The compressibility evaluation should be guided by the integration of geological engineering,integrating rock fabric characteristics and multi-scale mechanical parameters to establish,and optimize fracturing plans.

Key words: conglomerate, geology-engineering integration, multi scale, hydraulic fracturing, fracability

中图分类号: 

• TE384