莺歌海盆地浅层天然气生物降解及混源特征

利用天然气地化识别技术研究了莺歌海盆地浅层天然气生物降解及混源特征。研究结果表明，该区天然气遭受生物降解后，除正构烷烃浓度降低，被降解组分碳同位素变重外，在降解作用微弱的天然气中还检测出生物成因的烯烃。在莺歌海盆地中央泥底辟带，存在母质类型相似，但片地不同演化阶段的多套气源岩，具有生成不同成熟度天然气的物质基础。该区普遍存在由生物气（或低成熟气）与热成因气（有的已被生物降解）混合而成的混合天然气，泥拱活动产生的（微）裂隙为天然气运移及混合提供了主要通道。随气藏埋深变浅，生物气（或低成熟气）的比例增大，混合天然气的δ^13C变轻。由于生物降解作用将热成因气中的CO2转化为甲烷，混合作用补充了富烃的新烃气（生物气和低成熟气），从而改善了热成因气的品质，有利于该区富烃天然气的形成。     

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浅层复合(混合)天然气藏广泛存在于含油气盆地中，有效鉴别浅层复合(混合)天然气藏中天然气的成因可为浅层气勘探提供有价值的信息。我国含油气盆地浅层天然气组分及碳同位素组成分布特征表明，浅层天然气在总体上显示相对较高的甲烷含量和相对较低的甲、乙、丙烷碳同位素比值。浅层复合(混合)气藏中天然气的来源决定了气藏不同的复合(混合)类型，如以生物气为主与低温热成因气的复合，以低温热成因气(生物-热催化过渡带气)为主与成熟/高成熟热成因气的复合，以及低熟油伴生气与微生物降解气的复合。浅层复合(混合)气无论是甲烷碳同位素分布特征还是组分组成特征大部分都与生物气与热成因气的混合气相似，但从重烃组分含量，乙、丙烷碳同位素比值及其差值的不同，可以判断浅层复合(混合)气藏中天然气各组分的主要来源。     

崖13-1气田油气混合特征研究

崖131气田位于莺歌海盆地和琼东南盆地交界处,其气源长期存在争论。采用天然气GS/MS分析新技术,根据该气田天然气生物标志化合物、有机包裹体生物标志化合物、储集层包裹体温度、油气轻烃组成及碳同位素等资料,对其天然气的气源和混合作用进行综合研究,结果表明:该气田的天然气为典型的混合气,由不同类型有机质、不同热演化程度气源岩生成的天然气(煤成气和高成熟—过成熟海相成因气,以海相成因气为主)混合而成,北区块是Ⅲ型、Ⅱ型干酪根成因的混合气藏,南区块主要是Ⅱ型干酪根成因的气藏。主力气源岩是崖南凹陷沉积中心下第三系崖城组、陵水组的浅海相泥岩,生烃母质具有Ⅱ型干酪根特征。该气田的凝析油为煤成油,在蒸发分馏作用下形成;琼东南盆地存在切穿多层烃源岩的深断裂,形成局部低压带,为产生蒸发分馏作用提供了重要地质背景。图5表3参6(傅宁摘)     

莺歌海盆地乐东气田天然气地化特征和成藏史

莺歌海盆地乐东气田储层流体存在明显的非均质性,天然气主要成分为甲烷、二氧化碳和氮气。热成因烃气来源于中新统梅山组-三亚组泥岩,氮气是烃源岩中的有机质在成熟-高成熟阶段的生成物,无机二氧化碳气可能来自深埋沉积地层中碳酸盐矿物热分解及其与粘土矿物反应生成的二氧化碳,或许有部分前第三系碳酸盐岩热解成因二氧化碳和少量幔源二氧化碳加入。依据化学组成和碳同位素资料初步确定乐东气田至少存在3期天然气的注入,依次是生物气、热成因富烃气和无机二氧化碳,天然气的成藏时间大约距今1.2～0.1 Ma。沟通烃源岩的底辟断裂为天然气向上运移提供了良好的通道,由于高压流体的幕式排放诱发底辟断裂周期性开启和封闭,从而造就了莺歌海盆地底辟带气田的多源混合-幕式成藏特点。     

烃类气成因类型及其富气区的分布模式

天然气类型的划分是天然气地质学中一个重要的研究课题,不同学者有不同的划分原则。作者根据有机质类型及其热演化程度,将烃类气分为四大类:生物成因气、热降解成因气(又分偏腐泥型热降解气和偏腐殖型热降解气)、高温裂解气和生物降解气等。相应分出五类烃类气富气区分布模武:生物成因气区分布模式、热降解成因气区分布模式(又分偏腐泥型热降解气区分布模式和偏腐殖型热降解气区分布模式)、高温裂解气区分布模式和生物降解气区分布模式等,并对每一类富气区分布模式的形成机制及典型实例进行了解剖。气区的划分有利于不同成因类型天然气的勘探和远景评价。     

次生生物甲烷与生物降解作用的判识——以准噶尔盆地腹部陆梁油气田为例

“次生生物气”是指原油遭受生物降解后生成的天然气,由于其成分几乎全部为甲烷,因此又称为“次生生物甲烷”。以准噶尔盆地陆梁油气田为例,基于天然气组分和稳定碳同位素组成,结合伴生原油的轻烃地球化学特征,系统研究了次生生物甲烷和生物降解作用的判识方法。研究表明：当热成因天然气与次生生物甲烷混合时,甲烷碳同位素组成变轻,天然气组分变干。同时,此类天然气通常与埋深(地温)和生物降解油藏密切相关。通过原油的轻烃化合物特征可以有效判别油藏是否遭受生物降解。次生生物甲烷的生成常常还伴随着原生热成因气中重烃气组分的选择性降解,造成天然气干燥系数变大,重烃气碳同位素组成富集¹³C,甚至发生倒转。目前使用的各类天然气成因判识图版只适用于原生热成因气,使用时必须充分考虑是否存在各类次生改造作用的影响。     

莺-琼盆地生物气及生物—低成熟过渡带气特征与勘探前景

莺 琼盆地天然气资源丰富 ,天然气成因类型多 ,迄今为止 ,除在该区浅层和中深层发现以成熟—高成熟的热成因腐殖型气 (煤型气 )为主的天然气藏外 ,也发现了一些生物气及生物—低成熟过渡带气气藏 ,且均具较高的产量和一定的储量规模 ,其勘探前景广阔。     

白云凹陷天然气水合物气源条件再认识

运用南海北部珠江口盆地白云凹陷实际勘探的地质、地球化学资料,对该区天然气水合物的气源条件、气源成因和运移通道进行了分析和探讨.结果表明,盆地内巨厚的古近系-新近系烃源岩及第四系富有机质沉积岩可生产大量的热成因气和细菌成因生物气,为天然气水合物的形成提供了大量的气源;盆地内断裂和底辟构造发育,把热成因气源源不断从深部运移...     

中国陆相天然气成因类型及富集规律

中国陆相盆地天然气资源分布广泛,在东、中、西部及东南海域都有大中型气田发现。天然气主要有生物成因、生物-热复合成因、偏腐泥型热(裂)解、偏腐殖型热(裂)解及生物降解5种类型。富气凹陷主要有持续深埋型、脉动深埋型、持续中埋型、先缓后速中埋型及持续浅埋型5种类型。富气凹陷内的断裂背斜构造带天然气富集程度最高,多数是沿着古隆起或继承性构造成线状分布或围绕生烃洼陷成弧状展布。地温场强度高或煤系烃源层发育的中-深层及微生物生存条件好的中-浅层,是陆相天然气富集的两个最有利领域。     

莺歌海盆地天然气乙烷碳同位素异常成因分析

莺歌海盆地L15-1气田天然气具有独特性,其天然气乙烷碳同位素值高于盆地内其他气田。在系统分析天然气组分及同位素组成特征的基础上,结合烃源岩特征及底辟活动特征,综合分析了乙烷碳同位素异常的天然气成因与成藏过程。研究表明：L15-1气田天然气来自梅山组成熟度较高的煤型气,富含CO₂,未遭受明显的生物降解。造成L15-1气田天然气乙烷碳同位素值偏高的根本原因是海侵背景下梅山组烃源岩的干酪根碳同位素值偏高,同时,烃源岩较高的成熟度起到一定的促进作用。L15-1气田天然气主要在烃源岩高成熟阶段生成,经底辟活动形成的断裂运移至浅层莺歌海组和乐东组充注成藏;而源岩早期生成的富烃气保存于中深层黄流组和梅山组。该研究有利于弄清该区天然气的分布规律,进一步指导该区天然气的勘探。     

阿姆河右岸酸性气田井口冲蚀及对策

中亚土库曼斯坦阿姆河右岸气田群为高含H_2S和CO_2的碳酸盐岩气藏,单井产量高,井口设备均出现了不同程度的腐蚀。初步分析认为其原因是生产过程中仅考虑酸性介质对气井井口的化学腐蚀,而没有考虑气体流速对井口的冲蚀作用,极大地影响了气田的安全生产。为此,通过对节流阀上下游阀道、法兰面均出现明显坑状腐蚀的进一步分析,明确了化学腐蚀和气体冲蚀的交互作用是井口磨损的主要影响因素,气流冲刷腐蚀坑的化学腐蚀产物会加速冲蚀损害;进而借鉴冲蚀与腐蚀运行环境下的多相管流管道的磨损计算理论,计算了该运行环境下的冲蚀极限速度,得到了不同生产工况下节流阀的抗冲蚀流量;最后,根据气田生产情况,针对性地提出了按气井配产要求来选择采气树类型、节流阀通径及类型冲蚀的技术控制策略。此举为气田安全生产提供了工程技术保障。     

山前地区深井超深井套管防磨与减磨技术研究

针对山前地区深井超深井钻井过程中套管磨损严重的问题,在分析套管磨损机理的基础上,开展了山前地区套管防磨与减磨技术研究,基于技术研究成果及应用实践,得到如下结论:1应用Power V等垂直钻井系统控制井眼轨迹,特别是上部井段的狗腿度和井斜,可明显减小侧向力和磨损量,缩短套管磨损时间;2应综合考虑套管磨损率、磨损系数以及钻杆耐磨带本身的磨损量,优选出效果最优的耐磨带;在狗腿度严重的位置,可考虑采用一定数量的橡胶钻杆卡箍来减轻对套管的磨损;3山前地区钻井液采用CX-300减磨剂能够显著降低磨损速率,减轻套管磨损程度,但在不同钻井液体系使用之前应进行优化分析以确定最佳使用量;4在迪那204井使用高密度钻井液体系,全部采用优选的高密度重晶石粉代替铁矿粉作为加重剂,整个钻进过程中未出现钻具及套管磨损,迪那204井易损件消耗量仅为邻井迪那203井的左右,防磨减磨效果非常显著。     

Biodiesel Projects Helpful to Ease Energy Shortage

Nearly 7,000 hectares of biodiesel forest will take shape in the northern province of Hebei in 2008, part of a national campaign to fuel the fast growing economy in a green way. In no more than five years, the Pistacia chinensis Bunge, whose seeds have an oil content of up to 40 percent, will yield five tons of fruit and contribute about two tons of high-quality biological diesel oil, according to the provincial forestry administration.     

State Energy Base Proposed in Inner Mongolia

Experts recently suggested China set up a state energy base in lnner Mongolia Autonomous Region to ease its energy thirst. The survey was co-conducted by senior researchers from the National Development and Reform Commission, Development Research Center of the State Council, Chinese Academy of Sciences and the Ministry of Finance. To plan and establish strategic energy bases at state level is in line with the principle of ＂giving priority to energy saving and diversifying energy consumption with the utility of coal at the core.＂     

Influence of Shale Oil Boom in North America upon nternational Crude Price Flucturation

正Current stituation of shale oil development in the world The US The country is blessed with abundant shale oil resources and had matersed whole sets of theories and technologies needed for their exploration and development after years of practices.According to an assessment of shale oil resources in major countries and regions of the world issued by the U.S.Energy Information Agency(EIA),the US ranks the second in the world with its 6.8 billion tons of technically recoverable shale oil(shale oil in place is about 136.3 tons).About 8plays had been confirmed to have     

A Sintering-resistant Pd/C Composite Catalyst for Ethylbenzene DehydrogenationDeveloped by CAS Institute of Metals

Carbon deposition is a commonplace phenomenon occurringin the catalytic reaction process, in particular inthe system of direct dehydrogenation of ethylbenzene,because the reactant - ethylbenzene molecules on thesurface of metal oxide catalysts are prone to quickly formcarbon deposits, leading to deactivation of catalysts. Recently,the associate research fellow Mr. Liu Hongyangand the research fellow Mr. Su Dangsheng of the StateShenyang Material Science （United ） Laboratory of theInstitute of Metal Research, CAS by taking advantageof the carbon deposition process during direct dehydrogenationof ethylbenzene have ingeniously designeda Pd/C composite catalyst. This catalyst in comparisonwith the traditional commercial carbon nanotubesupported Pd catalyst shows a significantly improved performancein terms of its catalytic activity and sinteringresistantability.     

ZPEB Overseas Markets Keep Steady and Efficient Development

In recent years, Zhongyuan Petroleum Exploration Bureau （ZPEB） has made rapid development in overseas petroleum markets through its integrated reorganization. A new international business plattbrm established, aimed at becoming a highly ranked contractor with international petroleum engineering technology. ZPEB has expanded its business scope and scale, regulated the market structure,     

New Era for China-Brazil Relations

China and Brazil celebrated the 40th anniversary of establishing diplomatic relations between the two countries in July this year. Bilateral relations between China and Brazil have entered a new stage, and experts expect the already extensive cooperation between the two countries to deepen and broaden as Chinese President Xi Jinping made a state visit to Brazil in mid-July, which is his first state visit to Brazil since he assumed the office last year. The visit to China＇s largest trade partner in Latin America is at the invitation of Brazilian President Dilma Rousseff.     

Large Scale Ethylene Production Package Technology SuccessfullyDeveloped by CNPC

The CNPC Group has successfully developed a largescaleethylene production package technology with independentintellectual property rights, which has beensuccessfully applied in the 1.2 Mt/a ethylene revamp andexpansion project at the Daqing Petrochemical Complex（DPC）.     

Recent Advancements in Petroleum E & P Equipments in China

The role of equipments in oil and gas exploration and development had never been attached with so much importance as that in shale oil and gas boom in the U.S. With the help of massive hydraulic fracturing and horizontal drilling techniques, the U.S., the world＇s No. 1 oil importer even started to dream about energy self-sufficiency with its proudly high production of shale oil and gas from several major shale plays in the country. However, what behind this remarkable achievement are powerful multi-stage hydraulic fracturing machinery and smart tools for directional drilling.