摘要
研究多煤层储层能量垂向分布特征及其决定的含气系统性质具有重要的科学意义。基于油气田地质学及煤层气开采实践将煤储层空气渗透率1×10-3μm2(原地渗透率0.1×10-3μm2)作为划分具有统一压力的含气系统和无统一压力的含气系统的界限值,不同性质含气系统的储层能量具有不同的表现形式。以黔西织纳钻孔实测煤岩物性为分析资料,结果显示:该区代表岩性孔渗性极差,发育于三级层序边界的煤层空气渗透率小于1×10-3μm2,同时吸附性较强,形成无统一压力的含气系统,而其他煤层则单独形成具有统一压力的含气系统。多煤层垂向发育多套具有统一压力的含气系统时,则应优先开采侧压面较高储层能量较大的煤组段。多煤层储层能量垂向分异的决定因素是煤岩系的渗透性,其中含煤岩系酸性环境下的特殊成岩作用是岩层物性变差的主要因素。发育于最大海泛面附近的煤层镜质组分多,孔渗性较好,易于形成具有统一压力的含气系统。现代构造应力场大小是影响煤层渗透性的大小的重要因素。六盘水多煤层为典型的无统一压力的含气系统,而织纳部分区域含煤层组或单煤层为具有统一压力的含气系统。
Study of vertical distribution characteristics of reservoir energy and gas-bearing system is of important scientific importance.Based on petroleum geology and coalbed methane exploration,air permeability 1×10-3 μm2（or in-situ permeability 0.1×10-3 μm2） of coal bed reservoir was used as the threshold value of dividing unified pressure gas-bearing system（UPGS） and discrete pressure gas-bearing system（NUPGS）.Reservoir energy of gas-bearing systems with different features has different manifestation.This study took borehole Zhina in western Guizhou drilling as an example to analyze physical properties of coal-bearing rocks.Out results show that representative rocks are poor in porosity permeability,with air permeability in the third-level coadbed less than 1×10-3 μm2 and relatively strong adsorption,thus forming the NUPGS.But other coal beds form the UPGS individually.When several UPGSs was developed vertically within multi-coalbeds,the coal beds which have high reservoir energy and high lateral pressure surface should be preferentially mined.Determinant of vertical distraction of multi-coalbeds reservoir energy is permeability of coal measure,but the main factor which worsens physical property of rocks is special diagenesis in acidic environment of coal measure.The coalbeds developed in the MFS have high vitrinite and better porosity-permeability,which are prone to forming the UPGS.The scale of modern tectonic stress field is an important factor affecting the permeability of coal reservoir.The Liupanshui multi-coalbeds are a typical NUPGS,while multi-coalbeds or individual coalbed in the part Zhina area are UPGS.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2013年第1期139-144,共6页
Acta Geologica Sinica
基金
国家自然科学基金项目(编号40730422)
国家重大科技专项(编号2011ZX05034)
国家青年科学基金项目(编号41202115)联合资助成果
关键词
多煤层
储层能量
含气系统
成因
multi-coalbeds
reservoir energy
gas-bearing system
mechanism
