摘要
四川盆地南部下志留统龙马溪组存在着一套厚度介于30~50 m的富有机质页岩(TOC>2%),但在开发过程中不同层段的页岩气产量差异巨大,利用原有评价标准进行页岩气层划分的结果与实际产能之间存在着较大的矛盾。为此,通过分析大量的实验数据,基于页岩气储层评价指标对比,探讨了原有评价标准与评价结果之间存在矛盾的原因,结合生产动态资料开展了页岩气层类型划分方法研究,建立了以游离气为核心参数的新页岩气层类型划分方法及标准,并在川南威远区块进行了页岩气开发实践验证。研究及实践结果表明:①存在上述矛盾的原因是没有充分考虑页岩气赋存方式对产气量的控制作用;②新标准主要由TOC、吸附气含量、脆性矿物含量、孔隙度、游离气饱和度等参数构成,新、旧标准的最大差异是前者将吸附气含量和游离气含量进行了区分,并利用容易获得的含气饱和度代替游离气含量参数;③研究区页岩气层可划分为游离型、吸附型、过渡型(混合型)共3种类型,其中游离型硅质页岩气层是该区龙马溪组页岩主要的高产层段,过渡型页岩气层是潜在的有利目的层段;④实践证实新分类标准具有很好的适用性。结论认为,新方法能够更有效地区分不同类型的页岩气层、准确界定页岩气高产层段。
There is a set of organic rich shale(TOC>2%)of 30–50 m in thickness in the Lower Silurian Longmaxi Formation of the southern Sichuan Basin,but during its development,the shale gas production rate varies greatly in different layers.There is a big contradiction between the classification result according to the original evaluation standard and the actual productivity.To this end,this paper discusses the reasons for the contradiction between the original evaluation standard and the evaluation result based on the comparison of shale gas reservoir evaluation indicators,by analyzing a large number of experimental data.Then,combined with the production performance data,the shale gas reservoir classification method was studied,and a new shale gas reservoir classification method and standard with free gas as the core parameter was established.Finally,the new method was verified based on the practical shale gas development in the Weiyuan Block of southern Sichuan Basin.And the following research results were obtained.First,the reason for the above mentioned contradiction is that the control effect of shale gas occurrence mode on the gas production rate is not fully considered.Second,the new standard is mainly composed of TOC,adsorbed gas volume,brittle mineral content,porosity and free gas saturation.The main difference between the new standard and the old standard is that adsorbed gas content and free gas content are distinguished and the free gas content is replaced with the easily obtained gas saturation in the new standard.Third,the shale gas reservoir in the study area can be classified into three types,namely free type,adsorption type and transition type(mixed type).The free-type siliceous shale gas reservoir is the main high-yield interval of Longmaxi Formation shale in this area,and the transition-type shale gas reservoir is the potential favorable target interval.Fourth,the practice has proved that the new classification standard is of good applicability.In conclusion,the new classification method can distinguis
作者
石强
蒋春碧
陈鹏
陈云天
王秀芹
刘凤新
SHI Qiang;JIANG Chunbi;CHEN Peng;CHEN Yuntian;WANG Xiuqin;LIU Fengxin(PetroChina Research Institute of Petroleum Exploration&Development,Langfang,Hebei 065007,China;Peng Cheng Laboratory,Shenzhen,Guangdong 518000,China)
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2021年第2期37-46,共10页
Natural Gas Industry
基金
国家科技重大专项“四川盆地及周缘页岩气形成富集条件与选区评价技术与应用”(编号:2017ZX05035)。
关键词
页岩气
气层类型
页岩岩性
游离气
吸附气
高产层段
四川盆地南部威远地区
下志留统龙马溪组
Shale gas
Gas reservoir type
Shale lithology
Free gas
Adsorbed gas
High-yield interval
Weiyuan area of southern Sichuan Basin
Lower Silurian Longmaxi Formation
