DF1井氮气泡沫欠平衡钻井实践与认识

氮气加泡沫欠平衡钻井是当前国际上已经成熟的一种钻井新技术。其优点是静液柱压力低,漏失量小,携屑能力强,对油气层损害小,保证水敏性地层钻井安全;可及时发现油气层,提高单井产量;因而能够最大限度地发现和保护中、低压低渗油气藏,以获取比常规过压钻井高得多的经济效益。在大牛地气田DF1井的施工应用中,针对本工区低压、低渗、水敏的特点,使用该项技术,很好地解决了工区内使用普通泥浆造成对产层污染的问题,并取得了成功。     

松南深层火成岩储层的损害分析与保护技术

松南火成岩的储层特征中石英发育裂隙,发育构造微裂缝,由于天然气气层存在易于移动、易被压缩,且存在束缚水含量高、低压敏感性强、高毛管力等特点,导致气层更容易受到损害,从钻井取心、测井解释和有关的地质描述看,深层储气层普遍存在着裂隙。在对松南深层储层物性的认识以及实施常规钻井技术下储层潜在损害方式、损害程度研究的基础上,研究分析了钻井、完井等各个阶段保护技术的作用原理,制定了针对性的储层保护方案。研究实践表明,同时采用欠平衡钻井工艺,实施屏蔽暂堵的承压堵漏方案,采用优质非渗透钻井液完井液体系,改善侵入储层滤液性质,基本满足深层勘探钻井完井过程中保护储层的技术需求。现场应用表明,各项储层保护措施的实施在保护储层、地质资料需求和勘探发现等方面取得了良好的效果。     

煤层气储层伤害机理与水平井双层管柱筛管完井技术

煤储层具有高吸附性、低渗透性、易压缩与易破碎的特征,煤层气水平井钻完井过程中常常造成煤储层伤害,导致煤层渗透率和单井煤层气产量大幅度降低。通过实验分析,揭示水平井钻完井液中的固相颗粒、流体流动诱导产生的固相成分对煤储层微裂隙堵塞成因,阐明煤层气水平井钻完井中储层伤害的机理。在此基础上,提出水平井双层管柱筛管完井技术,分析其减轻煤储层伤害的机理,即通过冲管水力冲击作用消除水平井壁钻井液泥饼,清除井壁附近堵塞微裂隙煤粉,并在近井地带产生应力增渗作用。相对于煤层气常规的多分支水平井及分段压裂水平井,水平井双层管柱筛管完井的稳定日产气量、稳产周期均大幅提升。该技术在沁水盆地南部部分区域推广应用显示,3号煤层气井平均日产气量提升到20 000 m3,同时实现15号煤层气的开发突破,平均日产气量提升到10 000 m3以上。研究成果对于降低煤层气水平井钻完井过程中的储层伤害,提高煤层气井产量具有重要的理论和实践意义。      

南海西部高温高压小井眼水平井钻完井储层保护技术研究及应用

南海西部东方13-1气田D7H井为国内海上第一口高温高压水平井,储层物性以中低渗为主,使用高固相含量的钻井液易堵塞油气泄流通道造成储层伤害,加之海上完井方式制约,高密度钻井液在井眼滞留时间达10 d以上,不可避免地会加剧储层伤害程度。为充分保障该井储层保护效果,室内开展了大量的优选评价实验,优选出适合海上高温高压小井眼水平井钻完井储层保护油基钻井液,分析了高密度钻井液污染储层的机理,研究了返排压差、返排时间与岩心渗透率恢复结果的关系,提出了增加返排压差、延长返排时间提高储层保护效果的措施。实验结果表明：高温环境下高密度钻井液污染岩心后,初始渗透率恢复值约85%,当污染时间达到15 d时,渗透率恢复值骤降至30%,表明钻井液在储层滞留时间越长储层污染现象越严重;相同驱替条件下,渗透率恢复值随时间的延长而提高并趋于稳定;增加岩心返排时的压差有利于提高渗透率恢复值,返排压差达到12 MPa时,钻井液体系的渗透率恢复值可提高到80%以上。现场应用表明,D7H井试井机械表皮系数为0,清喷产量6.0×105 m3/d,超出配产产量近3倍,储层保护效果良好,为后续海上高温高压气田实施水平井进行规模化开发提供了宝贵的借鉴意义。     

东胜气田致密砂岩气藏钻井储层保护研究及应用

东胜气田上古生界下石盒子组为致密砂岩储层,部分区域储层物性好,具备不压裂自然建产潜能,钻井过程中存在井壁失稳及储层损害问题,各因素叠合造成的储层伤害阻碍了气层的产能释放。为进一步提升储层自然建产能力和增加单井产量,在储层渗透率恢复率的基础上,通过储层伤害影响因素分析,引入钻井液侵入深度定量化评价方法,深化了储层伤害机理认识,明确了低密度、无土相、低失水和强封堵的钻井液对策,室内优选了防水锁剂和致密承压复合暂堵剂,优化形成了无土相复合暂堵高酸溶钻井液,储层渗透率恢复率提高至91.11%,泥浆侵入深度降低46.28%。形成的钻井液在锦66井区推广应用,平均单井产量提升11%,并实现3口井自然建产,进一步提高东胜气田致密砂岩储层高效勘探开发的效果。     

玻璃微珠低密度无固相钻井液在DP3井中的应用

针对大牛地气田的低压低渗地层,为减轻钻井泥浆对气层造成的伤害,并验证水平井中欠平衡技术对盒3气层的增产效果,在DP3井的大位移水平井中采用玻璃微珠低密度无固相钻井液,实施欠平衡钻井技术,收到了良好的效果。     

入井工作液顺序接触煤岩储层损害实验评价

致密煤岩具有高毛管压力和比表面积大等特点,在钻井、完井和增产改造过程中,流体侵入将造成储层损害,显著降低工程技术效果。以往文献仅报道了单项工作液对煤岩储层的损害,忽视了工作液顺序接触煤岩储层损害的叠加效应。以川南煤田古叙矿区上二叠统龙潭组煤样为研究对象,开展了流体之间配伍性实验、钻井完井液与压裂液顺序接触煤样对渗透率损害实验。单项工作液储层损害评价实验结果表明,压裂液对储层的损害最严重,钻井完井液次之;工作液配伍性和顺序接触损害评价实验结果表明,与钻井完井液接触后,瓜胶压裂液损害最严重,离子平衡压裂液次之,活性水压裂液较轻,清洁压裂液最轻。顺序损害实验反映了工程实际过程,为入井流体评价和优选提供理论依据,有利于促进煤层保护和煤层气高效开发。      

使用纳米碳酸钙降低低孔低渗煤层气储层伤害

传统暂堵剂难以封堵低孔低渗煤层气储层中的大量纳米级别孔隙.通过煤岩显微观测、钻井液基本性能测试、泥饼清除实验、煤岩孔隙分布实验和气体渗透率实验,探讨了纳米碳酸钙降低低孔低渗煤层气储层伤害的效果.结果表明:纳米碳酸钙材料只有在水溶液中保持纳米级的分散状态,才可能对低渗煤岩起到暂堵作用;基于纳米碳酸钙的可降解钻井液既能封堵低孔低渗煤岩中微米级别孔隙,也能封堵其中的纳米级别孔隙;经过生物酶和稀盐酸双重解堵后,煤岩渗透率恢复值达77.17%~97.98%,储层保护效果好;煤岩孔隙分布实验可以在纳米尺度上研究纳米材料对低孔低渗储层的暂堵效果.研究成果可为纳米碳酸钙在低孔低渗煤层和页岩钻完井过程中的应用奠定良好技术基础.      

煤层气井储层保护钻井工艺

采用合适的钻井工艺是保护煤层气储层免受伤害, 从而提高煤层气井单井产量的关键环节。煤层气井储层保护钻井工艺包括低压钻井工艺、常规屏蔽暂堵钻井工艺和边钻边完井工艺。本文在介绍这些工艺的基础上, 分析了煤层气储层伤害的机理, 提出了相应的防护措施。      

高阶煤煤层气井产量递减规律及影响因素

为揭示高阶煤煤层气井产量递减规律，基于沁水盆地南部樊庄区块10余年的开发数据，通过数值模拟、统计分析等方法，对现有开发技术条件下高阶煤煤层气井产量递减点（即煤层气井产量开始递减时的煤层气采出程度）、递减类型及影响因素进行分析。结果表明:樊庄区块煤层气井产量递减点平均为25%，单井平均递减点为21%，大部分井在排采4 a后开始递减；煤层气井递减点由基质渗透率和裂缝半长决定，基质渗透率和裂缝半长越大，单井有效控制半径越大、有效控制储量越多，递减点越大；基质渗透率越高，裂缝半长增加引起的递减点增幅越大。由此可知，渗透率是煤层气井递减类型的主控因素，渗透率越高，递减指数越小，递减速度越慢。随着渗透率增加，递减类型依次为线性递减、指数递减和双曲递减。综合分析认为，储层平均孔隙半径越大，煤的应力敏感性越弱，煤基质收缩对渗透率的改善程度越大，导致储层动态渗透率越高，递减速度越慢。该研究为合理控制高阶煤煤层气井产量递减具有指导意义。移动阅读      

CSAMT 法在辽西康杖子区深部探矿中的应用

可控源音频大地电磁法(CSAMT)具有探测深度大、横向分辨率高、抗干扰能力强的特点,在深部找矿勘探中有着重要的指导意义。肖家营子铜钼矿床是辽西地区一个大型矽卡岩型金属矿床,大部分矿体是隐伏矿体,矿区外围的康杖子区与本区有相似的成矿地质环境,成矿地质条件优越.矿体与围岩电性差异明显,通过应用CSAMT,矿体具有低电阻特点,根据成果推断解释,对深部有利成矿部位进行了钻探验证,取得了理想的探矿效果,在矿区外围取得第二深度空间找矿重大突破。     

Geography in general education in Nigeria

This paper traces the development of geographic education in Nigeria and examines the views of geographers, other academics, students and the public at large about the importance of geography. Geography's value is immense despite the non-professional nature of the discipline. Nevertheless, there is a need to define geography's status and ensure career prospects for students. The Nigerian Geographical Association (from classroom teaachers to top geographers) must promote geography, improve its status in schools and universities, and continuously restructure its content and methods to address pertinent social needs.     

Trends in landslide occurrence in Nepal

Nepal is a mountainous, less developed kingdom that straddles the boundary between the Indian and Himalayan tectonic plates. In Nepal, landslides represent a major constraint on development, causing high levels of economic loss and substantial numbers of fatalities each year. There is a general consensus that the impacts of landslides in countries such as Nepal are increasing with time, but until now there has been little or no quantitative data to support this view, or to explain the causes of the increases. In this paper, a database of landslide fatalities in Nepal has been compiled and analysed for the period 1978–2005. The database suggests that there is a high level of variability in the occurrence of landslides from year to year, but that the overall trend is upward. Analyses of the trends in the data suggest that there is a cyclicity in the occurrence of landslide fatalities that strongly mirrors the cyclicity observed in the SW (summer) monsoon in South Asia. Perhaps surprisingly the relationship is inverse, but this is explained through an inverse relationship between monsoon strength and the amount of precipitation in the Hill District areas of Nepal. It is also clear that in recent years the number of fatalities has increased dramatically over and above the effects of the monsoon cycle. Three explanations are explored for this: land-use change, the effects of the ongoing civil war in Nepal, and road building. It is concluded that a major component of the generally upward trend in landslide impact probably results from the rural road-building programme, and its attendant changes to physical and natural systems.     

2010年的美国铀矿业

2010年,美国铀矿总共施工7 209个钻孔,总进尺1 493 520 m;生产铀1 628.55 t;铀矿业总支出费用为2.773亿美元,其中铀矿地勘费支出为3 450万美元,占铀矿业总费用的12.44%。铀矿地勘钻探费用为4 460万美元,占铀矿业总费用的16.08%。     

地下水环境中的硫代砷研究进展

硫代砷是富硫化物地下水中砷的重要形态,对环境和人类健康有潜在威胁。目前硫代砷研究程度尚低,本次主要针对国内外地下水（地热水）中硫代砷的存在形态,水文—生物—环境地球化学过程,样品保存,定量检测方法等方面进行研究。结论如下:pH, 氧化还原电位,硫化物含量和微生物作用等是影响地下水中硫代砷稳定存在和形态分布的重要因素。含铁矿物能与水中的硫代砷形成配位键对其进行吸附,吸附性普遍弱于（亚）砷酸盐,因此,地下水中硫代砷可能表现出更强的迁移性。用于硫代砷检测的自然水样在采集中可采取过滤,速冻,厌氧和低温短期保存的操作流程,以减缓该形态的转化甚至消失。色谱联用ICP-MS系统可用于自然水样中硫代砷的分离定量检测,紫外—可见分光光度法和X射线吸收光谱法在不同场景下也可对硫代砷进行定量和表征分析。地热水和浅层地下水中均可能存在硫代砷,由于水样中硫代砷的不稳定性,室内检测和分析难以准确反映现场过程,因此,野外样品保存技术和现场检测方法的更新可能在未来有更大研究空间,值得进一步探索。     

花岗岩地区地下水水文地质特征分析

通过对泰安市岱岳区花岗岩地区地下水的形成条件、地下水类型、分布状况、水文地质特征以及地下水补给、径流、排泄条件的分析,指出了花岗岩地区供水方向。     

Recent advances in aquaculture in Japan

Conclusions During the last ten years, aquaculture, especially mariculture has undergone remarkable expansion to counter-balance the gap between the supply and demand of fishery products in Japan. Its expansion has also been supported by the traditional preference of the Japanese people for seafood. Mariculture is now being forced to change its structure due to adverse economic circumstances such as the rise in the cost of energy, feeds and other materials for culture, low market prices, deterioration of environmental conditions, and many other factors. Before these constraints can be resolved, advanced scientific knowledge and technologies must be integrated to develop new types of aquaculture. Expansion of maricultural activities to more open-sea and off shore areas would be one route to follow. Technologies for the development of formulated diets not only for young but also for adults and larvae, establishment of feeding standards, prevention of epizootic diseases must support the establishment of modern aquaculture.The culture-based fisheries, or marine ranching, is becoming a subject for further development in Japan. Much research work has been conducted with a great degree of governmental support. Establishment of a net work of seedstock production farms has made it possible to carry out releasing experiments on a large scale. A newly integrated restoration system could be developed on the basis of these experiments, even though the profits resulting from the artificial restoration of stocks is not thouroughly verified at present. The commencement of a national scheme for culture-based fisheries would be a manifestation of the enthusiasm of the Japanese fish industry.     

Some Measurements of Radon in Soils and in Stream-Water in County Durham

Radon is a radioactive gas emanating naturally from uranium rich granites and shales. It may be emitted from the ground surface into the atmosphere as a gas, or it may be dissolved into stream water and transported over distance. The levels of radon gas in soils at ground surface depend on a number of factors relating to the source of the gas and to its transmission. Igneous rocks contain the highest mean concentrations of radium and uranium. The depth of cover is relevant also. Surveys over the years by the National Radiological Protection Board (NRPB) and others have indicated that the highest concentrations in the United Kingdom occur in Cornwall, Devon and northeast Scotland. However, recent reports have indicated that high concentrations of the gas may be detected in small pockets in counties outside of those considered at high risk. This survey relates to a series of measurements taken in and around Darlington, County Durham. The results showed the presence of small areas with strong concentrations of radon in soil gas, but only minor levels of dissolved gas in stream waters.     

内蒙古苏尼特地下水氟污染形成机理研究

为了研究内蒙古苏尼特地区地下水氟污染机理,本文运用水文地球化学分类方法,从水文地质、水化学特征两方面研究其地下水的水质特征、氟的起源、分布规律及污染形成机理。研究结果发现:高氟地下水的主要水质类型为HCO3—Na型,pH值在7.08～9.38之间,氟浓度与井深有关,即井越浅,氟浓度越高;地下水中氟浓度最高达14.78mg/L,5～9月地下水氟浓度相对增长率在7.8～23.1之间;F-浓度与Li+、Br-相关系数达0.89和0.82,受断层影响的深层地下水中F-浓度几乎与Li+、Br-没有相关关系,这暗示着氟来源于浅部,并受到强烈的蒸发作用影响而使水中的氟浓缩;地质调查发现该地区还有数个萤石矿存在,显微镜分析结果证实表层土壤中普遍存在CaF2,地下水中的氟来自CaF2。高氟地下水存在于潜水层,深部含水层的地下水可供开采。从断层带涌出的水对潜水层有稀释作用。