2016年2期

湘中地区涟源凹陷石炭系测水组泥页岩储层特征

发布时间:2016-09-05阅读次数:

【期数】2016-2

【作者】苗凤彬1,王强1,白云山1,谭慧2

【机构】1.中国地质调查局武汉地质调查中心,武汉 430205; 2.湖南华晟能源投资发展有限公司,长沙 410004

【关键词】泥页岩储层;孔隙类型;孔隙度;含气性;测水组;涟源凹陷

【中文摘要】石炭系测水组是涟源凹陷重要的页岩气勘探层位,针对页岩气藏自生自储、低孔低渗的特征,进行泥页岩储层特征研究是该区页岩气勘探与开发的关键问题。基于野外露头、钻探井及样品实验测试数据等资料,对测水组泥页岩储层分布、矿物组成、物性、含气性等特征进行了细致分析。测水组泥页岩在凹陷中部褶皱带厚度最大、埋深适合;泥页岩中脆性矿物含量超过70%,有利于天然裂缝的发育与后期的压裂改造;泥页岩内微孔隙与裂缝较为发育,孔径分布范围3.71 ~ 19.07nm,以介孔为主,具有较大的孔比表面积,孔径与总孔隙体积随埋深增加呈减小趋势;储层孔隙度为1.0% ~ 6.2%,平均为3.5%,渗透率变化较大,受裂缝发育程度的影响,为典型的低孔低渗非均质储层;受埋深较浅的影响,样品整体含气量较低,分布在0.16 ~ 0.49m3/t,但等温吸附测试的吸附气量远大于解析气量,表明在合适的埋深下测水组仍具有较好的储气能力。综合评价认为,涟源凹陷测水组泥页岩具有形成优质页岩气储层的潜力。

【英文摘要】The Carboniferous Ceshui Formation in Lianyuan Depression is regarded as an important shale gas exploration layer. Based on the characteristics of “self-generation and self-accumulation” and “low porosity and low permeability”, the study on shale reservoir is a key issue in the exploration and development of shale gas. Based on a vast amount of data from outcrops, well cores and experimental analysis, the reservoir characteristics of Ceshui Formation are analyzed in detail, such as the regional distribution,mineral composition, physical properties and gas content. The shale reservoir of Ceshui Formation in the central fold belt have a greatest thickness and an appropriate buried depth. And it has high contents of brittle minerals more than 70%,which is favorable for the generation of natural fractures and the late fracturing treatment. Pores and natural fractures in shale reservoir are common. The micro-pore size is ranged in 3.71~19.07nm and the mesoporous with high specific surface area are predominant. the micro-pore size and pore volume have a general trend of decreasing with increasing burial depth. Reservoir porosity is ranged from 1.0% ~ 6.2% with an average of 3.5%. The permeability which is affected by the natural fractures in reservoir varies greatly and the shale reservoir have a severe inhomogeneous property. The gas content of shale samples with 0.16-0.49m3/t is low because of the shallow burial depth. But the adsorbed gas content of the samples is more than the gas content,and the shales still have a large storage capacity with an appropriate burial depth. The comprehensive evaluation indicate that the Ceshui Formation in Lianyuan Depression can be an excellent reservoir for shale gas.

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