The project of geological survey of unconventional oil and gas was organized by the Oil and Gas Survey of the China Geological Survey. And a series of projects were carried out in this project, including geological survey of coal bed methane in Jixi Basin of Heilongjiang Province, the geological survey of oil shale in Songliao Basin and its surrounding areas, the in-situ test production of oil sands in the western slope of Songliao Basin, the geological survey of continental natural gas hydrate, the construction of the Muli natural gas hydrate field observation station in Qilian Mountains, the geological survey of helium in Guanzhong area of Shanxi Province and national survey of unconventional oil and gas resources, and a large quantity of basic data were acquired. Besides, a series of breakthrough and important progress have been achieved in well Heijidi-1, well Heijidi-3 and well Heijidi-4, and the potential of unconventional oil and gas resources in China has been known preliminarily, such as oil shale, oil sands, continental natural gas hydrate, helium, and coal bed methane in Jixi Basin. The project has an important impact in the fields of coalbed methane, oil shale, helium, etc., which has boosted confidence in unconventional oil and gas exploration and development, and promoted the deep integration of scientific and technological innovation and geological survey, and furthered the development of unconventional oil and gas discipline.

煤系气是非常规天然气领域的重要组成部分,也是近年来非常规天然气领域研究的热点.总结煤系气研究进展,明确亟待解决的重要科学问题,对于完善煤系气地质理论、推动煤系气勘探开发具有重要意义.当前煤系气研究进展主要表现在以下5个方面:①基于煤系地层沉积特点,总结了煤系气共生成藏的6个基本地质特征;②初步划分了煤系气共生组合方式,分析了煤系气4大成藏要素及其配置关系的控气作用;③分析了煤系含气系统叠置性地质成因,提出了叠置煤系气系统的识别与评价方法及控制叠置含气系统合采兼容性的地质要素;④总结了煤系"三气"共探合采理论研究、技术方法、产层贡献识别技术及合采产层优化组合与"甜点"评价;⑤在煤系气资源评价与有利区预测方面进行了有效的探索性研究.在对研究现状总结的基础上,提出了煤系气领域亟待解决的重要科学问题:①煤系气储层精细描述及可改造性评价;②煤系气资源评价方法及有利区优选;③煤系气开发甜点区(段)评价技术;④叠置煤系气系统合采兼容性评价.这些问题的解决,将有利于推动煤系气地质理论发展和煤系气资源的高效开发利用.

煤系中煤层气、致密砂岩气和页岩气叠置组合极具开发潜力,但具有赋存类型多样、成藏组合类型复杂、储层力学性质和工程响应差异大等特点,探索煤系"三气"共探共采技术是实现煤系气经济高效开发的必然要求.研究煤系气储层特征,合理选择目标层位,确定射孔位置,优化压裂施工工艺和参数,实现多类型产气层均衡改造,可最大限度降低层间干扰,充分释放多产气层组的整体产气潜力.本文以鸡西盆地梨树井田HJD1井下白垩统城子河组煤层、煤系泥质岩和煤系致密砂岩互层发育段为研究对象,系统研究了煤系非常规天然气储层特征,优选了煤系气开发有利层段,优化组合了合采产层,探索了与煤系多类型储层特征相匹配的分段射孔、水力压裂工艺,优化了压裂施工流程与工艺参数.结果表明:城子河组煤层与煤系暗色泥岩和砂岩薄互层段含气量高、生烃潜力好,煤系气资源条件优越;优选了煤层与煤层、煤系泥页岩和煤系致密砂岩与煤层、煤系泥页岩-煤系致密砂岩等岩性组合的合采目标层段;优化施工方案为增加射孔段长度(煤层厚度的1.8～6.3倍、砂泥岩含气层厚度的1.2～3.0倍)、提高前置液比例(45％～55％),采用"大液量(1200～1800 m3)、大砂量(5.7～10.4 m3/m)、大排量(9.33～10.28 m3/min)、高砂比(7.9％～9.4％)、高注入压力(45.0～46.7 MPa)、多级阶梯式加砂"和投球分压施工工艺,通过煤系多类型储层差异性压裂实现储层均衡改造,达到了较好的体积压裂改造效果.研究工作对煤层群发育区煤系气高效勘探开发具有借鉴意义.

新疆准南西山窑组煤层众多,含气系统的研究不仅可以在垂向上有效揭示含气量的变化规律,深入分析低煤阶煤层气的富集主控因素,还可以为后期煤层气压裂施工提供重要的参考.根据研究区内所施工的多个煤层气井钻探涌漏水情况,共识别出西山窑组3个主要含水层和平面上对应的4个富水中心,研究发现西山窑组内3个主要含水层均与三级层序的底部边界垂向位置高度吻合;通过对煤储层压力影响因素的分析,认为煤层埋深和含煤岩系泉域对于准南地区局部储层压力分布具有重要的控制作用;西山窑组主力煤层埋深介于700～1 000 m的区域是含气量和煤储层储层压力匹配的有利地带,是研究区内煤层气勘探开发的有利埋藏深度;根据岩心柱、煤储层压力、含气量变化和层序地层划分结果,将准南西山窑组中下段划分为2～3个相对独立的垂向叠置含气系统,分割各含气系统的关键层是区域内稳定发育的灰黑色泥岩,发育于研究区东侧三角洲平原环境的垂向含气系统发育较简单,而处于研究区西侧三角洲前缘-湖相环境的垂向含气系统则相对复杂.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

基于中国地质调查局组织施工的2口煤层气参数井资料,分析了准噶尔盆地南缘玛纳斯地区煤储层特征,综合影响煤层气富集与开发的储层参数,优选2#、5#煤层段采用大液量、中高排量、低砂比、变粒径支撑剂、多级阶梯式加砂压裂工艺进行储层改造,并采用地面微地震监测方法评价了压裂效果.研究表明:研究区中厚煤层群发育,煤层总厚度大、层间距小,且主要为原生结构的长焰煤.煤岩显微组分以镜质组和惰质组为主,储层微观孔隙发育,且主要为组织孔和溶蚀孔.煤储层孔隙度8.8％～14.5％,比表面积0.624～9.585 m2/g,孔容较大,孔隙连通性较好,渗透率0.0012～1.9286 mD,属中高孔—中低渗型储层.区内2#、5#煤层埋深大、含气量高、储层压力与能量高,但压裂施工中注入压力高、加砂效率低,储层改造难度较大.微地震监测结果显示,压裂所产生的人工裂缝以垂直缝为主,呈SE—NW展布,裂缝长度、宽度及影响体积都较大.压后放溢流时,放喷口气体可点燃,初步显示研究区具有良好的产气潜力.

页岩中吸附气含量是页岩总合气量中的重要组成部分.页岩吸附特性及其影响因素研究对于预测页岩总含气量及评价页岩气资源潜力具有重要的意义.柴达木盆地北缘侏罗系大煤沟组为一套湖相暗色泥页岩,分布广泛,有机碳含量高,已钻探获得页岩气发现.为研究这套泥页岩的吸附特征和影响因素,选取包括柴页1井岩心在内的40件泥页岩样品进行了有机地球化学、储层性能、岩石矿物学和含气量等一系列实验测试,分析了泥页岩有机碳含量等参数对吸附能力的影响.结果表明研究区大煤沟组泥页岩最大甲吸附气含量随压力增大而吸附能力逐渐增强,至一定程度达到饱和后不再增加;泥页岩中的有机碳、氯仿沥青“A”和黏土矿物可有效吸附和溶解甲烷,对吸附能力产生积极影响;在页岩热演化程度总体偏低的情况下,液态烃和可溶有机质大量存在并占据孔隙空间从而降低了泥页岩的比表面积,对其吸附能力产生消极影响.

1 研究目的(Objective) 受美国粉河等盆地低煤阶煤层气商业开发成功的启示,以低煤阶为典型特征的新疆地区煤层气成为国内研究的新热点和勘探开发的新领域,准噶尔盆地南缘是新疆煤层气资源最为富集的区域之一,也是国家能源局煤层气“十三五”规划的重点战略突破区.南缘中西段中侏罗统煤层气勘查研究程度极低,富集地质条件不清、资源潜力不明.中国地质调查局设立公益性煤层气基础地质调查项目,部署实施煤层气参数井并优选优质煤储层进行压裂改造与排采产气测试,获取低煤阶煤储层和产能参数,分析富集成藏条件、探索高陡构造厚煤层低煤阶煤层气的压裂排采工艺技术、拓展新疆煤层气勘探新领域、明确新疆低煤阶煤层气勘查开发利用前景,引领带动煤层气产业发展.

For the practice of petroleum exploration,the traditional petroleum geological theory has made great contributions to the development of petroleum industry. But, with the development of petroleum exploration into unconventional petroleum,the traditional petroleum geological theory and insight have come across with many problems and challenges,which can not direct unconventional hydrocarbon exploration effectively.In the perspective of condition of unconventional hydrocarbon accumulation,“source”is not only the rock generating hydrocarbon, but also reservoir and target;tight rock can be effective reservoir;enclosed mechanism of unconventional hydrocarbon is different from the conventional hydrocarbon;continuous and quasi-continuous hydrocarbon accumulation is not controlled by traditional trap condition;detention and short distance migration can form hydrocarbon reservoir;the evaluation methods of storage conditions are not exactly the same as conventional hydrocarbon.In the perspective of hydrocarbon accumulation mechanism,hydrocarbon reservoir can be formed under the mechanism of non-buoyancy in continuous large area;in the perspective of state hydrocarbon occurrence, besides free state,hydrocarbon can be accumulated in the states of adsorption and dissolution;in the perspective of distribution model of hydrocarbon enrichment,except for trap and high point, hydrocarbon can be accumulated in basin sub-sag and slope,sag-wide oil-bearing.The unconventional hydrocarbon resource around the world is more than 4 times of conventional hydrocarbon resource,indicating tremendous exploration prospect.

页岩储层特征对于页岩气的赋存状态、含气量和后期开发均具有重要意义.湖相页岩多处于生油窗阶段,其储层特征与海相页岩区别较大.以柴达木盆地北缘中侏罗统页岩为研究对象,利用岩芯观察、有机地球化学分析、XRD矿物成分分析、低温氮气吸附、FE-SEM以及甲烷等温吸附等手段分析页岩储层的岩石类型、地化、矿物组成、孔隙结构和含气性特征.结果表明,与海相页岩相比,柴达木盆地北缘中侏罗统页岩具有“两高两低两种类型”的特点,即有机碳含量高、黏土矿物含量高,热演化程度低、脆性矿物含量低,有机质类型以Ⅱ、Ⅲ型为主.较低的热演化程度导致样品有机质孔隙发育较少;有机酸的溶蚀作用及矿物的转化作用是次生孔隙形成的主要因素.与海相页岩不同的是,高丰度低演化程度导致该演化阶段以产液态烃为主,且样品中可溶有机质含量较高,它对于样品的孔隙结构和甲烷赋存状态都有影响,表现为随比表面积增大,样品等温吸附实验结果呈现下降的趋势.对于高丰度低演化程度湖相页岩储层特征的研究,不仅为柴达木盆地北缘中侏罗统页岩气的勘探开发提供地质依据,同时也完善了页岩气地质理论.

At present,shale gas exploration in China has made a significant progress,and we have established four statelevel shale gas demonstration areas that include the Fuling Jiaoshi dam,Changning—Weiyuan,Zhaotong and Yanchang.Shale gas production in last year has reached 13*108m3,which the yield of Fuling Jiaoshi dam reached the

The shale gas exploration in China has achieved remarkable profits,and four national shale gas demonstration zones（Fuling Jiaoshiba,ChangningWeiyuan,Zhaotong,and Yanchang）have been established.Recently,nearly 400 drilling wells have been accomplished,including 143 vertical wells and 130horizontal wells.But the shale gas production varies

Great breakthrough has been made in the exploration of lacustrine shale gas in China,but little research on reservoir of salt-water lacustrine shale was carried out.Organic geochemical analysis, mineral composition analysis and pore structure analysis of reservoir of the Palaeogene Xiaganchaigou For-mation lacustrine shale in western Qaidam Basin has been done by the authors.(1 ) The organic content has intense heterogeneity in the 0.1 2%~1 .35% range,the content of chloroform bitumen “A” is high <br> and the organic matter is mainly of type Ⅱ.(2) The content of carbonate is the highest with an average of 27.8%,and then clay minerals and quartz.There are 38.2% of the samples have anhydrite,which re-flects the typical salt-water lacustrine environments.(3)The organic matter micro-pores observed in the SEM are less developed,the shape is irregular and pore size is large.Intergranular pores are mainly mi-cronl-sized in diameter,while micro-fractures are mainly less than 1 μm in width.Mesopores have most of specific surface area and pore volume of shale pores,and are main places for gas adsorption and storage. The chloroform bitumen “A” influenced the pore structure of the samples.(4) The content of clay min-erals is low and brittle minerals is high in research area,which is comparable with the series of gas-contai-ning shales in U.S.and with the Lower Paleozoic shale in the Sichuan Basin,are conducive to creating cracks,and are easy for fracturing.

Characteristic of shale reservoir is important to the occurrences of shale gas,gas content and the exploitation（Chalmers and Bustin,2008;Gasparik et al.,2013）.The lacustrine shale at oil window stage is quite different from marine shale.This study use quantities of testing data from cores and outcrops from the basin edge to analyze the reservoir characteristics in Lacustrine Shale of Middle

Shale gas exploration have yielded remarkable achievements recently in China,and four national demonstration areas for shale gas exploration and production have been established respectively as FulingJiaoshiba,Changning-Weiyuan,Zhaotong and Yanchang.During recent few years,nearly 400 wells have been drilled including 143 exploratory wells（vertical wells）and