国外致密油勘探开发新进展及借鉴意义

New progress and reference significance of overseas tight oil exploration and development

系统调研了国外致密油勘探与开发最新进展(尤其是最为活跃的北美地区),针对致密油资源利用过程中普遍存在的定义多样化、储量计算方法不适用、过于依赖新技术与政策等几个突出问题,提出了相应的解决思路。结果表明:综合已有致密油及页岩油定义,结合致密油特征,从方便储量计算的角度,致密油定义可统一为以吸附或游离状态赋存于未纳入常规油田产层的低渗储层或地层深部致密岩石中(包括原地致密烃源岩,如泥页岩;与烃源岩互层或紧邻的致密储层,如致密砂岩、致密碳酸盐岩、致密岩浆岩、致密变质岩等),必须通过水平井或多级压裂等资金密集型开发技术才能实现经济采出的轻质石油聚集,进一步可分为2大类5个亚类;通过积极探索针对极低孔渗储层的物性测试技术和测井反演方法是建立致密油储层定量评价方法的有效途径之一,在储量评估时,借鉴基于开发动态的产量递减法对可采储量进行评价是更为切实可行的做法,同时,储层物性(孔隙度、渗透率)上限也应根据实际情况进行调整;此外,成功的致密油开发更需要政府制定积极有效的扶持鼓励政策,从而保障致密油资源的勘探与开发。

This study systematically investigated the latest exploration and development of overseas tight oil reservoirs,especially in the North America with the most active activities.Aiming at some prominent problems such as diversified definitions commonly existing in the application process of tight oil resources,inapplicable reserve calculation methods and excessive dependence on new technologies and policies,a corresponding solution was proposed herein.The results show that based on the existing definitions of tight oil and shale oil in combination with characteristics of tight oil,and from the perspective of facilitating reserve calculation,it can be defined as light petroleum accumulation in a free or adsorbed state in low-permeability reservoirs excluded from conventional pay zones or deep tight rocks （including in-situ tight oil source rocks,such as shale; the tight reservoirs interbedded with or adjacent to source rocks,such as tight sandstones,tight carbonates,tight magmatic rocks and tight metamorphic rocks）,which cannot be economically recovered unless using capital intensive development technologies such as horizontal well and multistage fracturing,etc.Further,it can be mainly divided into two types and five subtypes.Active exploration of the physical property testing technology and logging inversion method for extremely low-permeability reservoir is one of the effective ways to establish a quantitative evaluation method for tight oil reservoir.During the process of reserve evaluation,it is more practical to evaluate the recoverable reserve using the production decline method,which is based on development data.Meanwhile,the upper limit of reservoir physical properties （porosity and permeability） should also be adjusted according to actual situation.In addition,successful development of tight oil requires the government to actively formulate effective supporting and encouragement policies,thus safeguarding the exploration and develop