页岩气钻采技术综述

页岩气开采已成为全球资源开发的一个热点。页岩气储集层通常呈低孔、低渗透率,开采寿命长,生产周期长,采收率变化较大,且低于常规天然气采收率。不同于常规天然气的开采特点决定了页岩气开发具有其独特的方式。水平井技术对于扩大页岩气开发具有重大意义,水平井的成本一般是垂直井的1～1．5倍,而产量是垂直井的3倍左右。水平井技术结合geoVISION随钻成像服务和RAB钻头附近地层电阻率仪器等LWD技术可进行更高效、更合理的开采。压裂增产技术是页岩气开采的另一种方式。清水压裂技术用于产生更密集的裂缝网络,形成额外的渗透率,使气体能更容易流向井中,从而生产出大量地层天然气;多层压裂技术常常用于垂直堆叠的致密地层的增产：重复压裂技术用于在不同方向上诱导产生新的裂缝,从而增加裂缝网络,提高生产能力;还有最新的同步压裂技术。即同时对两口或两口以上的井进行压裂。这些压裂技术结合室内实验和测井技术,使得页岩气具有更大的发展潜力。     

美国页岩油开发现状及其巨大影响

美国继页岩气开发取得巨大成就后,在不放弃页岩气的同时,又将开发重点转向页岩油.推动美国页岩油开发的根本原因,是页岩气的快速发展推动天然气价格大幅下降,拉大了油气价差,促使美国液体成分丰富的页岩矿区将开发重点从天然气转向液体成分,从而使美国本土48个州的原油产量从2008年开始增加. 此外,部分页岩矿区的页岩油储量丰富也是原因之一. 目前美国页岩油开发的主要矿区是Bakken页岩层和Eagle Ford页岩层,其中Bakken 页岩油产量在2010年达到近40×l04bbl/d,计划2015年增至80× 104bbl/d;虽然现在Eagle Ford的页岩油产量低于Bakken,但从长远来看,其发展前景更好.不同机构均预测,由于页岩油的外发,美国原油产量会大幅增长,将成为全球第二大甚至最大的产油国. 美国页岩油开发将改变世界石油地缘政治格局,使世界能源供应的中心转移至美洲.同时,页岩油气开发已拉动美国炼油业和石化业复苏,给其国内经济恢复带来了动力. 中国亦拥有丰富的页岩油气资源,且水平井和压裂两大技术系列已整体上居于国际先进水平.但我国在页岩油气开发方面还存在一些问题,特别是在油气勘探开发区块管理上存在重大缺陷,必须继续进行改革,认真实施内外开放政策.     

Frack to the future: What enticed small firms to enter the natural gas market during the hydraulic fracturing boom?

The shale gas boom of the early 2000s saw the highest and most volatile natural gas prices and production in history. Advances in horizontal drilling, 3-D seismic imaging, and hydraulic fracturing made it highly profitable for firms to produce large quantities of shale gas. This period was also characterized by a shift in market structure. The U.S. natural gas market was historically defined by large firms, but a large number of small firms began entering the market after 2000. While small firms made a negligible contribution to natural gas production during the shale gas boom, their entry may signal overcapitalization, productivity growth, and increased responsiveness of natural gas markets to exogenous shocks. We develop a real options model of market entry and exit and use data on natural gas drilling activity to test three potential explanations for small firm entry during the boom: 1. technological advances, 2. land lease speculation, and 3. regime change in natural gas prices. Our analysis provides mixed support for the first explanation but strong support for the last two.     

页岩气产业远景展望及风险分析

页岩气革命给全球能源市场带来重要影响,并吸引了全球范围内对页岩气产业的广泛关注。页岩气促使美国从天然气进口国向出口国转变;促使加拿大逐渐脱离美国市场,寻求开拓新的油气市场;促使欧洲地区重新审视油气供需现状;促使亚太地区积极参与页岩气开发活动。页岩气产业的发展面临着价格、制度、效益、信誉和地缘政治等方面的风险。我国页岩气产业的发展,需要辩证地分析和借鉴美国的发展经验;根据气价变化调整生产和并购决策,规避价格风险;需要完善政策法规体系,降低产业发展效益风险和信誉风险;要立足国内资源,放眼全球视角。     

Marcellus Shale and structural breaks in oil and gas markets: The case of Pennsylvania

This paper first documents the rapid increase in Pennsylvania's share of U.S. natural gas production from ongoing development of the Marcellus Shale formation. It does stand to reason that the Marcellus Shale boom has made Pennsylvania natural gas production far more influential on aggregate oil and gas markets than before, but does such a differential effect appear in the data? Can we say, unequivocally, that the Marcellus Shale boom caused Pennsylvania's natural gas output to move the needle on national natural gas prices more so than before the boom occurred? These questions are investigated utilizing a threshold VAR model based on Tsay's (1998) test for unknown break points to investigate how, if at all, Pennsylvania's rapidly growing share of national natural gas production has altered the linkages between Pennsylvania's natural gas production and overall oil and gas prices. Findings indicate a structural break in the impact of Pennsylvania's natural gas production on natural gas prices occurring in early 2009, a date that matches well with the onset of the state's rapid production growth. Pre-break, there is minimal evidence that changes in Pennsylvania's production had a significant effect on the aggregate U.S. natural gas market; but when post-break data is included, an increase in Pennsylvania's production leads to a lower average national price of natural gas, which is transitory and lasts for only a few months. These results provide statistical support to the notion that Pennsylvania has become a substantial component of the U.S. natural gas market at least in the short-run.     

2013年国内页岩气钻采技术综述

2013年,国内在页岩气开采方面又取得了一些新进展,特别是页岩气水平井钻井、固井和压裂技术渐趋成熟,针对页岩气开发的需要,形成了页岩气水平井钻井、压前评价技术、大型压裂设计和压后评估技术,并围绕"井工厂"化作业,初步形成了钻井、压裂等一体化设计和优化,以及边钻井、边压裂、边生产的交叉作业模式,促进了国内页岩气开发进程。基于有关文献,简要介绍了国内在页岩气钻井技术、钻井液技术、固井技术、压裂技术和环境保护方面取得的新进展。在页岩气开发方面,如何在学习借鉴国外先进开采技术和国内已经取得经验的基础上,结合国内页岩气资源实际,积极探索更经济、更高效、更环保的"井工厂"开发模式,尽快形成完善配套的实验测试、钻井完井、排采和大型分段压裂、环保型压裂液、钻井废液(渣)和压裂返排液处理等页岩气开发关键技术,是今后仍需努力的方向。     

川西须五气藏完井方式适应性研究

随着勘探开发的不断深入,非常规天然气成为重要的接替资源。四川盆地非常规天然气资源量丰富,须五气藏为典型的砂泥岩互层致密非常规气藏,有效的完井方式是气藏实现提高单井产能、提高气藏可采程度的重要保障。国内外非常规气藏水平井主要采用多段压裂技术、降阻水压裂技术、同步压裂技术,开发效果显著;研究表明,基质裂缝、裂缝网络渗透率、水力裂缝间隙、水力裂缝传导率、岩石压缩性、水力裂缝半长、自然裂缝孔隙度,对页岩气水平井产能影响较大,钻井过程中要对近井地带的基质渗透率、裂缝网络渗透率和自然裂缝孔隙度进行保护。川西须五气藏储层脆性矿物含量与美国其他页岩气相当,同时储层具有天然裂缝发育的特点,完井方式需要考虑储层改造工艺、最大程度上实现缝网压裂的目的;通过深入研究,优选出川西须五气藏完井方式,优选套管射孔完井方式,采用水平井+多段水力压裂和储层改造完井方法进行开发。     

North American natural gas and energy markets in transition: insights from global models

This modeling comparison exercise looks at the global consequences of increased shale gas production in the U.S. and increased gas demand from Asia. We find that differences in models' theoretical construct and assumptions can lead to divergences in their predictions about the consequences of U.S. shale gas boom. In general, models find that U.S. High Shale Gas scenario leads to increased U.S. production, lower global gas prices, and lower gas production in non-U.S. regions. Gas demand in Asia alone has little effects on U.S. production; but together with the shale gas boom, the U.S. can have a large export advantage. Overall, models find U.S. exports level range from 0.06 to 13.7 trillion cubic feet (TCF) in 2040. The comparison of supply, demand, and price changes in response to shocks reveals important differences among models. First is how the demand shocks were implemented and how the model responds to shocks: static and elastic within each time period vs. endogenous to the long-term gross domestic product (GDP) growth. Second is how the supply response is expressed through fuel/technology substitutions, particularly the flexibility of cross-fuel substitution in the power sector. Identifying these differences is important in understanding the model's insights and policy recommendations.     

Modelling of fractured horizontal wells with complex fracture network in natural gas hydrate reservoirs

Shale gas resources (SGR), as a representative of natural gas hydrate reservoirs, have been the main energy supply for the energy consumption currently. The multi-scale pore structure of shale, complicated seepage mechanisms, including Knudsen diffusion, matrix deformation, stress sensitivity, non-Darcy flow and spatial fracture network stimulated by hydraulic fracturing technology have posed huge challenges to an accurate prediction and assessment of shale gas recovery. A full understanding of gas seepage mechanism of shale gas is the critical and scientific issue to develop carbon hydrogen energy resources effectively. It is very urgent to establish a comprehensive mathematical model to analyze the productivity capacity through simultaneously considering various flow mechanisms and fractures network system. To fill this gap, this paper presents a comprehensive numerical model of hydraulic fracturing horizontal well with discrete fracture network where embedded discrete fracture model (EDFM) is employed to characterize the coupled phenomenon between discrete fracture network and fractured SGR. And then two numerical discretization methods, e.g., finite difference and finite-volume, are used to numerically discretize the equations, subsequently, the Newton-Raphson iterative method is adopted to obtain the final solutions. Finally, the sensitivity analysis experiments are employed to investigate the effects of the key parameters. The results can provide some certain guidance for the optimization of stimulated treatment in natural gas hydrate reservoirs.     

国内页岩气开采技术进展

因页岩气开发具有资源潜力大、开采寿命长和生产周期长等优点,已成为当前能源研究的热点和突破口.自2009年以来,我国已在页岩气开发实验区钻井62口,其中24口井获得工业气流,这预示着国内页岩气资源开发全面铺开.页岩气储层与常规储层差异很大,必须采用先进技术,尤其是水平井钻井、完井及压裂技术,才能实现经济有效开发.介绍了国外页岩气开采技术以及国内近两年在页岩气钻井技术、钻井液技术、固井技术和压裂技术方面取得的经验,这些经验奠定了国内页岩气开发的技术基础.论述了页岩气开采面临的技术和环境问题,指出下一步页岩气技术发展方向.今后,需要结合国内页岩气藏特点,在借鉴国外新技术及国内经验基础上,通过工具研制、技术配套、方案优化,尽快完善适用于页岩气开发的水平井钻井技术;从流变性、封堵能力方面进一步完善油基钻井液体系,同时开展适用于页岩气水平井钻井的水基钻井液体系研究;针对页岩气水平井多采用油基钻井液的现状,进一步完善冲洗液、水泥浆体系及固井工艺技术.开发适合页岩气水平井多级压裂技术相关的井下工具、工作液和施工工艺,加强压裂裂缝动态监测,优化压裂设计.形成配套的钻井和压裂等作业过程中产生的废液、废水及废渣处理技术,重视贞岩气开采的环境污染评估,保证我国页岩气开发的健康发展.     

Introduction: North American natural gas markets in transition

Over many decades, energy markets have seen a variety of new technologies with the potential of replacing existing practices for providing conventional fossil fuels. Unlike synthetic fuels during the 1970s or hydrogen during the 2000s, however, hydraulic fracturing for producing natural gas shale resources has had a dramatic impact because it has been cost effective. This article describes a model-comparison effort organized by Stanford's Energy Modeling Forum and provides a brief overview of the principal findings by individual modeling teams that participated in the study.     

页岩气开发现状及成功开发页岩气的关键因素

介绍页岩气的性质、特点、全球分布情况以及国内外勘探开发现状,世界范围内,泥、页岩约占全部沉积岩的60%,页岩气资源前景巨大。全球页岩气资源量为456.24×1012m3,主要分布在北美、中亚和中国、拉美、中东、北非以及前苏联地区等。我国页岩气可采资源量约为26×1012m3,与美国大致相当。在目前的经济技术条件下,页岩气是天然气工业化勘探的重要领域和目标。北美油气生产商把页岩气藏作为重要天然气开发目标,并且取得了巨大成功。通过对北美页岩气藏的深入研究并系统总结其勘探开发历史与成功经验,认为其有效勘探开发的关键在于有政策引导和水平井、水力压裂等先进钻、完井技术的成功应用。我国页岩气资源潜力很大,但我国对页岩气的研究与勘探开发尚处于探索阶段。从勘探技术、钻井技术、开发技术和政策支持四方面论述了页岩气开发的难点和技术对策,提出了国内页岩气成功开发的工作思路,对国内开展相关技术的研究有一定的指导意义。     

A strategic analysis of the New Brunswick,Canada fracking controversy

Strategic insights into the previous conflict between the Elsipogtog First Nation and the New Brunswick (NB) Provincial Government are presented using a formal conflict resolution technique. The conflict surrounds the prospect of widespread hydraulic fracturing in NB, one of Canada's Maritime provinces on the east coast of the country. The hydraulic fracturing technique, used for mining natural gas trapped in shale rock formations, has recently received much attention. The process is strongly opposed by some groups, including the Elsipogtog First Nation, primarily due to the potential environmental impacts associated with the technique. Through the application of the Graph Model for Conflict Resolution, it is found that the status quo at the time of the conflict was the most likely outcome in this conflict. The previous Conservative New Brunswick government had a great deal of power in this conflict and it had demonstrated its intention to develop the shale gas in the province in the face of much civil unrest. It is discovered, however, that there is a potential resolution to the conflict that will appease the residents of NB, if a moratorium is issued concerning hydraulic fracturing.     

页岩气使全球石化产业中心重新向美国偏移

页岩气开采技术的突破,使美国天然气产量自2007年起大幅增加,并在2009年超过俄罗斯排名世界第一,天然气进口依赖度大幅减少。页岩气不仅改变了美国的能源格局,也使世界天然气市场格局悄然发生改变。加拿大转而在欧洲寻找买家,俄罗斯和中东等天然气主要出口国将面临挑战,但给欧洲和中国等主要天然气进口国却带来利好。常规天然气资源匮乏的国家,对页岩气勘探开发兴趣浓厚,纷纷制定激励措施,页岩气开采已成世界性趋势。石化巨头在美国掀起页岩气并购战,并在美国兴起了建设乙烷裂解装置的热潮。2015年前后,美国将成为中东之后乙烯衍生物成本第二低的国家。拥有成本和技术优势的美国乙烯衍生物将给世界石化产业带来更大冲击。国内石化企业用石脑油作裂解装置原料,副产大量丙烯,可考虑重点发展丙烯系列产品;充分利用裂解装置副产物,生产精细化工产品,还可以利用廉价的甲醇生产烯烃。我国具有巨大的页岩气储藏量,假如在短短数年内页岩气的产量能大幅增长,届时从天然气中就可分离出数量可观的乙烷,我国也将掀起裂解装置裂解原料轻质化的浪潮。因此,国内石化企业应密切关注中国页岩气的开发进程,提早为裂解装置裂解原料的轻质化作好准备。     

The real value of FracFocus as a regulatory tool: A national survey of state regulators

Over the last decade, domestic oil and gas production has increased dramatically because of advancements in the technologies associated with hydraulic fracturing and horizontal drilling. This boom generated a wave of new state laws and regulations, especially addressing disclosure of fracturing chemicals. In 2011 the chemical disclosure registry FracFocus.Org was launched to provide well-by-well chemical information to the public. Many states adopted FracFocus for chemical reporting. In 2013, Harvard Law School researchers issued a report concluding that FracFocus “fails as a regulatory compliance tool.” The report made serious criticisms regarding the utility of the registry; however, the report was incomplete because its authors never interviewed state regulators. This paper remedies that oversight. We surveyed regulators in twenty oil and gas producing states to determine how they view and are using FracFocus. The results contradict the most crucial claims of the Harvard report and indicate that states are quite positive about FracFocus and are using it in novel ways that go beyond the registry's original purpose. This paper represents the first comprehensive survey of state regulators and the first attempt to obtain a data-driven analysis of how FracFocus is being used and whether it is effective as a regulatory tool.     

Techno-economic analysis: Ethane steam reforming in a membrane reactor with H2 selectivity effect and profitability analysis

With the increased production of shale gas through a new drilling technology of hydraulic fracturing, much attention has been directed to various utilization methods for ethane accounting for about 7% of shale gas. As an efficient utilization method for ethane, ethane steam reforming in a membrane reactor is proposed in this paper to provide improved reactant conversions and product yields thus leading to a reduced operating temperature. To assess techno-economic feasibility of ethane steam reforming in a membrane reactor, parametric studies focusing on a H₂ selectivity and economic analysis predicting profitability from cash flow diagrams based on a purified hydrogen in Korea were performed simultaneously providing very useful design and economic guidelines to implement a membrane reactor for ethane steam reforming.     

Energy (in)security in Poland the case of shale gas

The large scale extraction of natural gas from shale rock layers in North America using hydraulic fracturing, or “fracking”, has prompted geologists, economists and politicians in various parts of the world to ask whether there are new reserves of this precious resource to be found under their soils. It has also raised a host of questions about the potential environmental impacts of extracting it. Drawing on research on both sides of the Atlantic, this paper assesses the most pressing issues for research and policy makers related to shale gas extraction. The paper first provides a survey of environmental and economic issues related to shale gas. It then turns to a case study of Poland, whose policy makers have been among the most fervent proponents of shale gas development in the European Union. We examine the status of shale gas extraction in that country and what the barriers are to overcome before commercial extraction can in fact take place, if at all.     

新疆油田火山岩气藏体积压裂机理研究及应用

进行火山岩气藏压裂改造时,通常采用形成单一裂缝的增产改造技术,气井稳产时间较短.借鉴页岩气开发理念,深入研究火山岩气藏体积压裂机理.根据缝内压力传导的力学模型,研究不同液体体系对压力传导的影响,分析无滤饼压裂液体系对体积压裂的作用,优选出压裂液体系;建立不同角度天然裂缝开启的力学模型,确立体积形成的关键力学条件,并针对火山岩气藏压裂目的层的地应力结构进行实际分析.从储层矿物角度出发,研究对比火山岩储层的脆性系数;根据力学条件,结合压裂工艺过程,建立相关模型,优化研究体积压裂关键工艺参数,包括排量、压裂规模等;分析降阻水、线性胶、浓胶液三种不同黏度液体对裂缝网络的作用.在上述研究基础上,针对新疆油田DX1413井实际地质条件,分析该井进行体积压裂的有利条件,并进行压裂设计与改造施工,对施工曲线、施工过程、施工结果进行分析,得到了一些有益的结论,这些结论对火山岩气藏的开发有重要的启迪作用.     

世界页岩气资源现状研究

页岩气的勘探开发引起国际社会的高度关注,其资源分布与资源潜力成为研究的热点。页岩气资源主要分布于北美、中亚、中国、中东、北非和非洲南部等国家和地区。据EIA最新的评价结果,全球页岩油和页岩气技术可采资源量分别为473×108t和207×1012m3,分别占油气资源总量的10%和32%。中国页岩气和页岩油技术可采资源量分别为31.6×1012m3和44.1×108t,分别居世界首位和第三位。世界页岩气技术可采资源量排名第二位、第三位的国家分别是阿根廷和阿尔及利亚,资源量分别为22.71×1012m3和20.02×1012m3。俄罗斯拥有102.19×108t页岩油技术可采资源量,居世界首位,阿根廷、利比亚、委内瑞拉和墨西哥等国也拥有丰富的页岩油资源。非常规油气已成为全球油气供应的重要组成部分,非常规油气产量占油气总产量的比例已超过10%。非常规油气勘探开发技术取得的成果包括连续型油气聚集理论、水平井规模压裂技术、平台式"工厂化"开发模式。将多学科的先进技术综合应用到勘探领域,是目前页岩油气勘探技术的发展方向。以美国为首的西方发达国家将继续引领全球页岩气勘探开发技术的潮流。     

页岩气水平井钻井液技术的难点及选用原则

我国页岩气资源勘探开发已全面铺开。针对页岩气的成藏特征,页岩气开发以浅层大位移井、丛式水平井布井为主。由于页岩地层裂缝发育、水敏性强,长水平段钻井中不仅易发生井漏、垮塌、缩径等问题,且由于水平段较长,还会带来摩阻、携岩及地层污染问题,从而增大了产生井下复杂情况的几率。解决井壁稳定、降阻减摩和岩屑床清除等问题是目前页岩气水平井钻井液选择和设计的关键。选择页岩气水平井钻井液的原则是确保井壁稳定、润滑、防卡和井眼清洗。油基钻井液可提高水润湿性页岩的毛细管压力,防止钻井液对页岩的侵入,从而有效保持井壁稳定,同时还具有良好的润滑、防卡和降阻作用,是国内外目前采用最多的钻井液体系。当采用水基钻井液的时,利用低活性高矿化度聚合物钻井液或CaCl2钻井液以降低页岩和钻井液相互作用的总压力;采用浓甲酸钾、Al3+盐,可以通过脱水、孔隙压力降低和影响近井壁区域化学变化的协同作用产生良好的井眼稳定作用;对于有裂隙、裂缝或层理发育的高渗透性页岩应使用有效的封堵剂进行封堵;但对于强水敏性页岩地层,水基钻井液在抑制性方面仍然存在局限性。从环境保护的角度出发,甲基葡糖苷钻井液在井壁稳定机理方面与油基钻井液相似,未来可望作为有效的钻井液体系之一。随着以页岩气为代表的非常规油气资源的不断开发,为了满足安全钻井和环境保护的需要,未来页岩气水平井钻井液技术的研究应围绕高效、低成本水基钻井液和低毒油基钻井液来展开。