全油气系统定量评价:方法原理与实际应用

Quantitative evaluation of whole petroleum system:principle and application

人类对油气的勘探开发和利用已超过150年,油气勘探进展大致划分为油气苗找油气、圈闭找油气、油气系统理论找油气和非常规油气藏勘探4个阶段。非常规油气勘探是对常规油气勘探的重大突破,在经典油气地质理论认为不可能形成油气藏的禁区发现了大量连续分布的非常规油气藏。非常规油气藏虽然需要采取特殊措施才能获得有效产能,但具有广泛连续的分布特征且资源潜力巨大,与常规油气藏的最大差异在于其运聚成藏不受浮力主导和圈闭控制。当前,非常规油气勘探在实践中遇到了一系列重大挑战,包括非常规与常规油气藏的差异性表征困难、无统一分类方案、分布边界不清、无量化判别标准、关联性不明、尚未建立起联合成因模式等。全油气系统概念的提出为复杂地质条件下常规和非常规油气资源的勘探开发提供了全新思路和新的理论指导,其研究内容涉及油气成藏全要素、形成演化全过程、资源分布全系列、预测评价全方位。基于全油气系统的学术思想,在国家重点基础研究发展计划(“973”计划)等项目课题的资助下,以油气门限控藏研究为切入点,重点剖析了中国6个代表性盆地(塔里木盆地、准噶尔盆地、四川盆地、鄂尔多斯盆地、渤海湾盆地和松辽盆地)12 237口探井中80 762个常规和非常规油气藏的钻探结果,并与北美地区已发现的常规和非常规油气藏进行对比,结合全球1 186个盆地已探明的52 926个油气藏的差异性统计分析,在全油气系统定量评价研究中取得了4方面成果:(1)发现全油气系统内普遍存在3类10种油气门限,揭示其成因机制和控油气特征,提出了研究方法和判别标准;(2)建立了油气运聚门限联合控油气资源形成分布模式,提出了有效资源量预测评价新方法;(3)建立了动力场控油气藏分布模式,提出了有利成藏领域和成藏区带预测评价新技术;(4)建立了分布门限组合控藏模式,研发了有利成藏区带和钻探目标优选新技术。全油气系统定量评价方法在常规和非常规油气藏成因分类、剩余资源预测、全球天然气水合物资源潜力评价等方面的应用成效展示了未来全油气系统研究的发展方向。

Human beings have been exploring,developing,and utilizing oil and gas resources for more than 150 years.The progress of oil and gas exploration can be roughly divided into four stages:oil and gas exploration from seepage situations,trap exploration,exploration by petroleum system theory,and unconventional oil and gas reservoir exploration.Unconventional oil and gas exploration is a breakthrough to conventional oil and gas accumulation,by which a lot of continuously distributed unconventional oil and gas reservoirs have been discovered in the forbidden area where it is impossible to form oil and gas reservoirs according to the classical petroleum geological theory.The unconventional oil and gas reservoir is characterized with extensive and continuous distribution and great potential for resources,but from which the effective capacity should be obtained by special measures.The biggest difference between unconventional and conventional oil and gas reservoirs is that unconventional migration and accumulation are neither dominated by buoyancy nor controlled by traps.At present,unconventional oil and gas exploration has encountered a series of major challenges in practice,including the difficulty in characterizing the differences between unconventional and conventional oil and gas reservoirs,unclear distribution boundary,unclear correlation,and the lack of a unified classification scheme,quantitative criteria,and a joint genetic model.The concept of the whole petroleum system provides new ideas and new theoretical guidance for the exploration and development of conventional and unconventional oil and gas resources under complex geological conditions.The research of the whole petroleum system includes the total factors of hydrocarbon accumulation,the whole process of formation and evolution,the full range of resource distribution,as well as the all-around prediction and evaluation.Based on the academic thought of the whole petroleum system,with the support of the National Basic Research Program of China(973 Program)and other projects,and taking the research of oil and gas thresholds-controlling accumulation as the breakthrough point,the drilling results of 80 762 conventional and unconventional oil and gas reservoirs in12 237 exploratory wells in6 representative basins in China(Tarim Basin,Junggar Basin,Sichuan Basin,Ordos Basin,Bohai Bay Basin,and Songliao Basin)are analyzed and compared with those of the conventional and unconventional oil and gas reservoirs found in North America.Further,in combination with the statistical analysis of the differences of52 926 proven oil and gas reservoirs in1186 basins around the world,four achievements have been made in the quantitative evaluation of the whole petroleum system.(1)It has been found that there are three categories and 10 types of oil and gas thresholds in the whole petroleum system,the genetic mechanism and oil and gas control characteristics are revealed,and the research method and discrimination criteria are also put forward.(2)The formation and distribution model of hydrocarbon resources jointly controlled by oil and gas migration and accumulation thresholds is established,and a new method for predicting and evaluating effective resources is proposed.(3)A model of oil and gas reservoir distribution controlled by dynamic field is established,and a new technology for predicting and evaluating favorable accumulation fields and zones is also put forward.(4)A reservoir-controlling model based on the combination of distribution thresholds is established,and a new optimized technology of favorable accumulation zones and drilling targets is developed.The application results of the quantitative evaluation method of the whole petroleum system in the genetic classification of conventional and unconventional oil and gas reservoirs,the prediction of residual resources,and the evaluation of the potential of natural gas hydrate resources around the world show a development direction of the research of the whole petroleum system in the future.