摘要
煤系气赋存态多种多样,储层属性复杂多变,经济高效开采模式尚处于探索起步阶段。分析了国内科技攻关和现场试验近期进展,初步总结关于煤系气开采模式现有认识,对比分析了不同模式的适用性和局限性,并以临兴区块示范工程为例分析归纳了产量曲线类型及其合采有效性特点,介绍了煤系气合采成功范例。以管柱结构设计和排采管控方式为主,考虑井型选择和压裂方式,将煤系气开采工艺初步归纳为分排、先分后合、合排3类模式。每类模式包括若干具体方式;这些模式和方式各有优缺点,分排及合排模式中的主要方式在应用中见到初步效果,先分后合模式目前尚处于设计乃至设想阶段。建议煤系气开采模式及其技术创新本着“因地制宜、取长补短、多措并举、有所侧重”的策略,根据气藏具体地质条件选用和发展适应性开采工艺。目前仅有的两个国家级示范专项工程推进了我国煤系气开采模式的创新,临汾示范区采用分区分采方式实现了煤系气开发规模快速扩展,临兴示范区探索“排气降压”诱控接续合排工艺初步实现了煤系多气经济高效合采。重点分析了临兴示范区煤系气开采工程示范效果,揭示了自然接续工艺下的煤系气生产规律,发现存在4种单井产量曲线类型,包括以解吸气多层合采为特征的I型曲线,以游离气-解吸气诱导控制接续合采的Ⅱ类、Ⅲ类曲线,以及单纯游离气产出的IV型曲线。工程示范结果展示,采用“排气降压”的诱控接续方式,可以在较为广泛的气藏条件下实现煤层气-煤系致密砂岩气、煤系致密砂岩气-页岩气的有效合采,是值得进一步探索和具有推广应用潜力的煤系气经济高效合采新模式。值得关注的是,具有工业价值的煤系多类型共生气藏均赋存在深部,而深部地层富水性往往微弱,使得“排水降压”传统模式难以奏效;而“排气降压”诱控接续恰恰针对于弱富水储层降压面临的这一局限,可能成为煤系气经济高效综合开发的一项重要技术。
Occurrence state and reservoir properties of coal measures gas(CMG)are complex and variable,so that the pattern of economic and efficient CMG production is still in the initial stage.For this reason,the progress of the research and field test for the production patterns in recent years in China is analyzed,the current understanding of the patterns is summarized,and the applicability and limitations of different patterns are compared.Then,taking the demonstration project in Linxing block as an example,the types and joint production effectiveness of production curves are discussed,and the successful examples of joint CMG production are introduced.Based on the string structure design and drainage control measures,combined with the selection of well pattern and fracturing method,the CMG production process is preliminarily classified into three patterns,i.e.layering,first layering then joint,and joint drainages.Each pattern includes several specific methods,each of which has its own advantages and disadvantages.The main methods in layering and joint drainages have preliminary effect in application,and those of the first layering then joint drainage are still in design and even idea.It is suggested that the CMG production pattern and its innovation should be based on some strategies,including adjusting measures to local conditions,learning from each other’s strengths to make up for each other’s weaknesses,combining multiple channels and focusing on some aspects,and the adaptive production technology should be selected and developed according to the specific geological conditions of the gas reservoirs.At present,only two national demonstration projects have promoted the innovation of CMG production pattern in China.The scale CMG development in the Linfen demonstration area has been rapidly extended by adopting the method of partition and separate production,and the economic and efficient joint production of various types of CMG has been realized in the Linxing demonstration area by developing the technology of the induced control continuation through pressure drop with exhausting gas.The analysis of the demonstration effect of the CMG production project is focused to the Linxing demonstration area,which reveals the CMG production law under a natural continuation method.It is found that there are four types of single well production curve,including the type I curve characterized by the multi-layer commingled production of desorption gas,the typeⅡand typeⅢcurves characterized by the commingled production of free and desorption gases induced continuation production,and the type IV curve of the single free gas production.The project demonstration results show that the effective joint CMG production can be realized under a wide range of gas reservoir conditions by using the induced continuation method of the pressure drop with exhausting gas,which is a new way of economic and efficient joint CMG production worthy of further research and application.It is worth noting that all types of CMG reservoirs with an industrial value exist in the deep strata where the water richness is often weak,which limits the traditional pattern“drainage and pressure drop”.However,the induced control continuation production through pressure drop with exhausting gas can make up for this major limitation,which is of universal significance for the economic and efficient CMG development.
作者
秦勇
吴建光
李国璋
王应斌
申建
张兵
沈玉林
QIN Yong;WU Jianguang;LI Guozhang;WANG Yingbin;SHEN Jian;ZHANG Bing;SHEN Yulin(Key Laboratory of CBM Resources and Reservoir-forming Process,Ministry of Education,China University of Mining and Technology,Xuzhou 221008,China;China United Coalbed Methane Corporation,Ltd.,Beijing 100015,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2020年第7期2513-2522,共10页
Journal of China Coal Society
基金
国家科技重大专项资助项目(2016ZX05066-01)
国家自然科学基金重点资助项目(41530314)。
关键词
煤系气
开采模式
开采方式
产量曲线
排气降压
多气合采
coal measures gas
production pattern
production method
gas production curve
pressure drop with exhausting gas
joint production of various gases
