Fluid evolution and hydrocarbon accumulation model of ultra-deep gas reservoirs in Permian Qixia Formation of northwest Sichuan Basin,SW China

The fluid evolution and reservoir formation model of the ultra-deep gas reservoirs in the Permian Qixia Formation of the northwestern Sichuan Basin are investigated by using thin section,cathodoluminescence,inclusion temperature and U-Pb isotopic dating,combined with gas source identification plates and reservoir formation evolution profiles established based on burial history,thermal history,reservoir formation history and diagenetic evolution sequence.The fluid evolution of the marine ultra-deep gas reservoirs in the Qixia Formation has undergone two stages of dolomitization and one phase of hydrothermal action,two stages of oil and gas charging and two stages of associated burial dissolution.The diagenetic fluids include ancient seawater,atmospheric freshwater,deep hydrothermal fluid and hydrocarbon fluids.The two stages of hydrocarbon charging happened in the Late Triassic and Late Jurassic–Early Cretaceous respectively,and the Middle to Late Cretaceous is the period when the crude oil cracked massively into gas.The gas reservoirs in deep marine Permian strata of northwest Sichuan feature multiple source rocks,composite transportation,differential accumulation and late finalization.The natural gas in the Permian is mainly cracked gas from Permian marine mixed hydrocarbon source rocks,with cracked gas from crude oil in the deeper Sinian strata in local parts.The scale development of paleo-hydrocarbon reservoirs and the stable and good preservation conditions are the keys to the forming large-scale gas reservoirs.

Path of Social Construction in Northwest Sichuan Plateau Pastoral Area

On the basis of main contents of social construction and key points of construction,this paper analyzes features of conditions of northwest Sichuan plateau pastoral area.The social construction at current stage mainly includes social cause in narrow sense,and social management at meso-level.The northwest Sichuan plateau pastoral area is faced with the best policy and development opportunity.However,there are still many weak aspects.Firstly,social structure is not coordinated with economic structure.Secondly,social construction ability of grass-roots government is weak.Thirdly,the ability to respond to public demands is low.Fourthly,there is a big gap in availability of basic public service.Finally,it presents path selection for social construction of northwest Sichuan plateau pastoral area:strengthen social construction ability of grass-roots government;promote social construction with livelihood projects as key projects;boost social construction taking advantage of ecological construction;develop basic public service with the aid of external forces;intensify evaluation system for supervision of social construction works.

Systematic Analysis and Optimization of the Agricultural Structure in Ethnic Regions in Northwest Sichuan Province

Based on introducing the basic conditions of the ethnic regions in northwest Sichuan Province,the thesis analyzes its agricultural development status,which can be classified into two aspects--rich natural resources and slow agricultural economic growth.Through the analysis on the agricultural structure of northwest Sichuan Province,it is found that the production efficiency and economic benefits of crop planting in this region are low,animal husbandry,as a major industry in pastoral region,sees high production efficiency,the agricultural production is still at the resource-oriented stage;its agricultural structure is still the farming-pastoral structure relying mainly on animal husbandry,planting is dominated by crop planting and potato planting,animal husbandry mainly produces dairy and beef;the ethnic regions in northwest Sichuan Province is endowed with the advantages to grow crops,beans and fruits as well as to produce beef,mutton and milk,among which,three industries,say fruit,beef and dairy are with increasing location quotient and gradually strengthening industrial comparative advantage,while the location quotient of the other industries is declining and their industrial comparative advantages are more stable.In order to promote the agriculture in northwest Sichuan Province to develop in breadth and depth,the thesis proposes the following measures and suggestions:the first one is to adhere to the development strategy of modern animal husbandry;the second is to appropriately improve the proportion of economic crops;the third is to accelerate the development of green food processing industry.

Prediction of the Distribution of Perennial Cultivated Grasses in the Northwest Sichuan Plateau, China under Climate Change

In order to determine the threshold and potential distribution of climatic conditions for perennial cultivated grasses in the Northwest plateau of Sichuan, China, the niche model is used to simulate the main climatic factors affecting the distribution of perennial cultivated grasses, and to predict the current and future climate change prospects. The results show that: 1) Wet index, accumulated temperature, isothermal, and annual average temperature range are the four major climatic factors affecting the distribution of perennial cultivated grasses in the Northwest Sichuan Plateau. 2) Model training and prediction data can be achieved well under the appropriate range of major climatic factors. 3) Under the background of climate warming, from now to 2080, the potential distribution of perennial cultivated grasses in the Northwest plateau of Sichuan, China will increase. The study aims to provide scientific decision-making basis for maintaining grassland ecosystem stability and promoting desertification management and even industrial restructuring of agriculture and animal husbandry.

The reservoir characteristics research of Devonian Jinbaoshi Formation,Northwest Sichuan Basin,SW China

A great breakthrough was achieved on the Middle Devonian's oil-gas exploration in the Longmenshan area in northwestern Sichuan.However,only the Guanwushan Formation was researched in detail.The underlying formation-Jinbaoshi Formation as a set of the potential well reservoir and its reservoir characteristics have not been discussed.Based on the section's fine description,thin section analysis,and core borehole logging,combined with petrophysical analysis,the reservoir characteristics,controlling factors,and evolution process of the Jinbaoshi Formation reservoir in the Longmenshan area are deeply studied in this paper.The results showed that the Jinbaoshi Formation has developed a set of sand-shale interbedding deposit of terrigenous clastic and carbonate rocks.The reservoir lithology is mainly quartz sandstone and calcareous quartz sandstone.The quartz sandstone reservoir has good physical properties,but the calcareous quartz sandstone has the characteristics of strong heterogeneity,low porosity,and permeability.Residual intergranular pores are mainly developed in the reservoir space.And the development of intercrystalline pores and intergranular dissolved pores can also be seen,but the development frequency is low,and the scale is small.Among them,the Devonian Jinbaoshi Formation quartz sandstone's average porosity is about 8%,and the highest is 18.43%.The main diagenesis types of the Jinbaoshi Formation are compaction,recrystalization,and dissolution.Compaction is the main reason for the destruction of original pores,and dissolution is the main driving force for later porosity and permeability improvement.Rock fragments,calcareous silty clasts,and bioclastic grains are the main dissolution objects.The formation of intergranular dissolved pores significantly improves the physical properties of the reservoir.Therefore,the reservoir development of the Jinbaoshi Formation is mainly controlled both by favourable sedimentary facies and diagenesis.Quartz sandstone and calcareous sandstone of the Jinbaoshi Formation were controlled by early sedimentary facies in the syngenetic rock stage and developed more early intergranular pores;in the early diagenesis stage,compaction-pressure solution and cementation resulted in residual intergranular pores.In the middle-late diagenesis stage,the calcareous cement is dissolved,and more pores were formed.

Genesis and characteristics of the dolomite reservoirs in Middle Devonian Guanwushan Formation, Northwest Sichuan Basin, SW China

A great breakthrough has been made on oil-gas exploration of the Middle Devonian Guanwushan Formation in Northwest Sichuan Basin.The further exploration shows that the dolomite reservoir is complicated with insufficient investigation.Taking the Middle Devonian Guanwushan Formation as an example,systematic study has been carried out on its reservoir character,mechanism and genesis of dolostone.The field and core data suggest that reservoir types of Guanwushan Formation consist of crystalline dolomite,breccia dolomite and reef dolomite,and reservoir space is characterized by intercrystal(dissolution)pores,residual pores among breccias,intragranular dissolution pores,pockets as well as fractures.Besides,pore structure is of good configuration,showing medium-low porosity and moderate permeability,with average porosity and permeability of 2.23%and 0.44mD respectively,which suggesting fracture-pore and fracture-cavity reservoir.Combined with the previous research,it is suggested that the reservoir of Guanwushan Formation was controlled by facies,dolomitization and two-step karstification,with reef-shoal facies being material base for reservoir development,early dolomitization being key factor for reservoir space preservation,polyphase karstification being foundation for reservoir development and tectogenesis finally finalizing the reservoir.

川西北高寒典型沙区植被恢复动态遥感监测研究

近几十年来,土地退化、沙化问题威胁着川西北地区草原生态环境和群众生产生活。为获取并定量分析沙区治理的植被恢复动态及趋势,探讨典型沙区的生态修复变化机制,本文以红原县瓦切镇典型沙区1984、2000和2021年3期长时序Landsat遥感影像为数据源,在ENVI 5.3和ArcGIS 10.2软件的支持下,通过植被覆盖指数(NDVI)与光谱混合分析(NDVI-SWA)相结合的方法提取植被覆盖度(FVC),运用土地动态度空间分析模型和转移矩阵分析川西北高寒典型沙区植被恢复变化特征。结果表明:(1)研究区植被覆盖度等级结构以高度植被覆盖度为主(占50%以上),且不同植被盖度类型存在明显空间差异;(2)1984年研究区植被覆盖情况最差,2021年植被覆盖情况最好,中度及以下植被覆盖度面积仅占4.71%。1984-2021年,变化幅度最大的是中度以下植被覆盖度情况,占比呈现出先增加后降低的趋势,相对而言,中高度、高度植被覆盖度处于较为稳定的变化状态。(3)各级FVC转移矩阵分析中,具体转化方向较为一致,主要是向高植被覆盖方向转化,表现为:中高等级向高等级转化;低等级向中低、中等级转化。

川西北地区2种典型人工林森林质量评价

人工林是川西北森林生态系统的重要组成部分,为了解其森林质量状况,以云杉(Picea asperata)和辐射松(Pinus radiata)为优势树种的2种典型人工林为对象,采用因子分析和聚类分析开展了森林质量评价。研究结果表明:(1)通过因子分析提取出4个主成分,累积方差贡献率为76.877%,能较全面地反映森林质量状况;(2)4个准则层的权重值表现为林木生长因子>林下灌木因子>林分郁闭条件>林下草本因子,说明林木生长因子对森林质量评价指标体系的影响最大;(3)根据森林质量评价综合得分,各等级样地数量占比分别为优10%、良40%、中10%、差40%;(4)川西北地区不同树种人工林质量分化明显,其中云杉人工林质量以“良”为主,辐射松人工林质量以“差”为主。研究结果有助于掌握川西北地区人工林森林质量状况,从而为后续开展森林质量精准提升奠定基础。

川西北某泥石流沟发育特征及易发性评价

川西北某泥石流沟位于汶川“5.12”8级地震中心影响区域岷江河谷,该区域地质构造复杂,新构造运动强烈,强震频发,加之受岷江河谷深切,地形陡峻,出露地层以软质岩为主,沟道及两侧物源十分丰富,强降雨条件下易引发泥石流灾害。通过收集区域地质资料、遥感解译、现场地质勘察和力学计算等方法相结合,从地形、物源和水动力条件等方面,研究了该区域某泥石流沟的发育特征并开展易发性评价,提出了相应的工程防治对策。研究结果表明:(1)川西北某泥石流沟为暴雨崩滑沟谷型泥石流,泥石流沟流域面积20.8 km^(2),固体物质总储量约258.9×10^(4) m^(3),可能的动储量约64.5×10^(4) m^(3);(2)100年一遇的泥石流重度为1.74 t/m^(3),平均流速为5.12 m/s,最大峰值流量为535.4 m^(3)/s,泥石流最大冲起高度为1.34 m,预测100年一遇的泥石流淤积厚度为4.8 m,具有中度易发性风险;(3)针对工程区的泥石流发育特征及易发性程度,建议以桥梁工程形式并留足净空通过泥石流沟,提出了泥石流防治对策与建议。研究成果对川西北山区铁路勘察设计和施工建设具有一定借鉴价值。

族类标签与王朝拓边:明代中后期川西北地区的社会分类和国家治理

聚焦明代川西北地区以族类标签为标识的社会分类,是考察王朝拓边进程的关键视角。15世纪时,明廷秉持羁縻导向的边关方略,对流行于川西北非汉社会的“大小”“牛羊”等二元族类标签之内涵缺乏了解。15世纪后期到16世纪前期,明廷尝试重新诠释川西北非汉社会语境中的“黑—白”族类标签,但因国家力量渗透边地的程度有限,“黑—白”标签的本地意涵与明廷定义在一定时期内共存。16世纪中后期,明廷的边地知识与地方社会实态之间存在明显张力,在王朝国家发动军事行动整饬边地秩序后,“番—羌”族类标签逐步成为向化程度深浅的代名词。明代川西北诸种族类标签的内涵演化是“中心—外缘”互动在社会分类层面微观而鲜活的呈现。

添加麦麸和乳酸菌对川西北高寒地区燕麦裹包青贮品质和有氧稳定性的影响

川西北高寒地区燕麦收获时含水量较高,环境温度较低,燕麦青贮品质不佳。本文为提高燕麦青贮品质,研究了自选乳酸菌发酵生物学特性,评价了麦麸和自选乳酸菌菌株对燕麦裹包青贮品质和有氧稳定性的影响,采用双因素试验设计:因素A,A_(0):0%麦麸;A_(1):30%麦麸;因素B,B_(0):对照;B_(1):Lactobacillus plantarum 160(LP160);B_(2):Lactobacillus brevis 248(LB248);B_(3):商业菌。每个裹包50 kg,每个处理3个重复。结果表明,自选菌株LP160和LB248在模拟冻融(20℃/-5℃)条件下生长迅速、产酸快。燕麦裹包青贮60 d后,添加麦麸后青贮干物质、粗蛋白、可溶性碳水化合物、乳酸显著增加(P<0.01),添加乳酸菌后青贮pH和氨态氮显著降低(P<0.01),其中A_(0)B_(1)组发酵品质最优,A_(1)B_(1)组营养品质最优,即LP160效果最优。综上,添加麦麸和自选菌株可以有效改善川西北高寒地区燕麦青贮品质和有氧稳定性,为该地区青贮饲料的制作提供了技术支持和理论依据。

基于碳酸盐岩储层裂缝表征与产能描述的开发技术对策——以川西北双鱼石区块栖霞组气藏为例

针对碳酸盐岩气藏试采期开发技术对策研究中存在的问题,在剖析裂缝表征方法和扩展气井产能概念的基础上,探索和揭示了不同类型储层裂缝特征相对应的气井产能变化规律,形成了碳酸盐岩储层裂缝表征与产能描述技术。文中研究明确了裂缝-孔洞型、裂缝-孔隙型和孔隙型3类储层酸压改造后形成的裂缝搭配模式与试井双对数曲线的对应关系;通过建立复合地层渗流方程,实现了对气井产能以及影响产能的动态储量、平均渗透率的描述,揭示了纯气井和气水同产井在早期、过渡期、平稳期和变化期4个阶段的产能变化规律,以此为依据提出了井位平面部署、靶体位置优化、钻井及储层改造工艺、生产井制度优化4个方面的对策建议。通过实施开发技术对策,取得了单井产量的突破,生产井水侵速度得到一定程度的控制。文中研究成果指导了气藏开发技术对策的制定,为同类型碳酸盐岩气藏的高效勘探开发提供了技术参考。

川西北高原高速公路沿线坡度对土壤养分含量的影响

以久马高速公路沿线不同坡度的12块样地作为研究对象,系统分析了不同坡度范围的土壤有机碳、铵态氮、硝态氮、速效钾、速效磷等含量的变化特征。结果表明:当坡度在10°~15°范围内时,土壤的有机碳、铵态氮、硝态氮、速效钾及速效磷含量明显高于其他坡度范围内的土壤养分含量,在其他坡度范围内土壤养分含量的差异较大。土壤养分含量随着坡度变化而呈现出不同的变化趋势,其中坡度在10°~15°范围内土壤养分含量最高。

川西北高原饲用燕麦产量和生殖性状相关性分析及综合评价

【目的】为筛选出适宜在川西北高原推广种植的饲用燕麦品种。【方法】通过田间随机区组试验,对17个饲用燕麦品种的生产和生殖相关性状进行测定,利用主成分分析法进行综合评价。【结果】17个燕麦品种中锋利的鲜草产量最高(51.42 t/hm^(2)),甜燕1号干草产量最大(16.28 t/hm^(2));相关性分析表明,鲜草产量与干草产量、倒伏率、穗长、株高、小穗数、旗叶长、旗叶宽、第三茎节粗呈显著正相关(P<0.05)。主成分分析将17个性状分为5个主成分,依次为小穗数、茎长、株高、叶茎比和分蘖数,累积贡献率达到86.35%。依据K-means聚类分析,将17个品种分为4个类群,第Ⅰ类群,株高最高、茎节数最多;第Ⅱ类群,鲜草产量最高、茎节最粗、旗叶长宽最大;第Ⅲ类群产量最少、旗叶面积最小、小穗数最少;第Ⅳ类群植株矮小,茎节数较少、鲜草产量偏低。【结论】依据5个主成分得分进行综合评价表明,悍马、甜燕2号、麦迪逊3个品种在川西北高原的产量、生殖相关性能优良,具有高产优质饲用燕麦的潜力,适宜在当地种植。

川西北高寒区冻融交替作用后土壤水热运移模拟研究

川西北高寒区在黄河和长江上游的水源涵养与补给、生态平衡中发挥着重要作用,该区土壤长期受到昼夜及季节性冻融作用影响,但土壤水分和热量在受到冻融交替作用后的变化规律,及其在草地退化及沙化过程中的作用还不明确。通过野外采集土样进行室内土柱模拟水热运移实验,利用有限元软件HYDRUS建立了一维土柱模型,开展基于冻融循环作用后的非饱和沙化草地和天然草地土壤水热迁移过程的数值计算研究,揭示不同冻融界面条件下沙化草地和天然草地土壤的水热分布特征、空间运移特性。结果表明:HYDRUS软件模拟沙化草地和天然草地土壤体积含水率的模拟结果R2>0.98,其平均值分别为0.997,0.996,模拟效果较理想;在土壤温度特性方面,模拟结果R2>0.98,平均值0.999,HYDRUS软件较好地模拟了川西北高寒区冻融交替作用后天然草地和沙化草地土壤温度和体积含水量的变化特征。通过模拟预测发现,反复冻融作用后,天然草地和沙化草地土壤体积含水率随时间变化均呈现上下波动的趋势,天然草地各土层体积含水率总体均高于沙化草地含水率;土壤温度模拟值呈现先波动上升后波动下降的趋势,且均呈现随着剖面加深,土壤温度逐渐降低的趋势,沙化草地土壤各层最高温度平均低于天然草地各层土壤温度。率定后的土壤水热运移数学模型能够较好地反映出川西北高寒区冻融交替作用后土壤水热的动态变化规律。将率定后的参数及当地的气象资料输入模型,可有效预测该地区冻融交替作用后的土壤水热运移规律。研究结果为该地区土壤沙化治理与预防,维护生态平衡提供科学依据和理论支持。

川西北地区须家河组二段致密砂岩储层特征及其主控因素

为明确川西坳陷北部地区上三叠统须家河组致密储层分布特征,通过岩心描述、测井解释和X射线衍射矿物分析,得到储层沉积微相类型和矿物组成特征,结合岩石薄片和场发射扫描电镜观察、孔渗和压汞测试等,得到的成岩作用及储层孔隙结构分析结果,开展了须家河组二段储层致密化影响因素研究,建立川西北部地区须二段储层综合分类评价标准。结果表明:须二段致密储层发育的主要原因为储层孔隙度受岩性控制,矿物组分的差异使须二段砂岩具有强胶结、中等压实和弱破裂的特征,中等压实作用有利于提高储层物性,强胶结作用增强了储层的致密性。研究结果可为该区致密储层发育的有利区域筛选及下一步开展勘探致密气藏有利目标区提供依据。

基于两种MCDM的四川汶川县农村环境保护和社会经济综合发展评估

科学全面的综合评估,是引导农村环境保护和社会经济综合发展方向的先决条件。该研究通过VIKOR与TOPSIS两种方法,分别对地处生态脆弱且地位重要的川西北汶川县,展开行政村尺度的环境保护和社会经济综合发展评估。结果表明:1)相较于TOPSIS方法,综合考虑群体效应(整体综合发展水平)和个体遗憾(发展制约因素)的VIKOR评估方法,对本地的综合发展评估更全面、深入;2)VIKOR方法评估得到汶川县整体综合发展水平较高,无论乡镇还是行政村尺度均呈现出显著空间分异特征,综合发展水平高值区沿县域西北-中部-东南一线分布,综合发展水平低值区主要集中于县域东北及中南部。3)TOPSIS方法评估得到汶川县整体综合发展水平处于中等,综合发展水平高值区沿县域西北-中部-西南一线分布,综合发展水平低值区与VIKOR方法评估结果一致。4)就评估结果而言,基于VIKOR方法因综合考虑了整体发展水平与短板因素,可能使部分行政村的综合发展水平差异缩小;TOPSIS方法则因未考虑正、负理想解之间的相对重要性,可能导致“逆序”问题。两种方法评估得到的主要差异聚焦于综合发展优秀区。5)借助VIKOR方法考虑个体遗憾的特点,认识到生态保育及村民自治水平是限制汶川县农村综合发展的两大关键制约因素,其中村民自治能力对于综合发展的提升发挥着重要作用。

人工湿地处理川西北散户农村生活污水的应用研究

景观型人工湿地用于处理川西北生态示范区散户农村生活污水,以补充河道生态需水和减少农村环境污染。选择在阿坝州茂县十里沟村开展现场示范应用研究,底部曝气、美人蕉与西伯利亚鸢尾等搭配种植、冬季搭建保温棚等应用于本湿地。连续7个月监测湿地进出水COD_(Cr)、NH^(+)_(4)-N、TN、TP等指标,分析其对当地生活污水的处理效果,考察低温运行时,西伯利亚鸢尾等4种植物在丙二醛(MDA)含量、氯化三苯基四氮唑(TTC)还原量、酶活力等方面的响应情况。结果表明,COD_(Cr)、NH^(+)_(4)-N、TN和TP夏季去除率为85.07%±2.59%、97.21%±1.33%、82.30%±3.37%和65.78%±1.55%,冬季较夏季分别下降18.57%、8.14%、11.35%和7.55%。出水COD_(Cr)、NH^(+)_(4)-N和TP基本能达到《地表水环境质量标准GB3838-2002》的Ⅴ类水质标准。低温下(4~9℃),美人蕉表现出较高的根系活力和污染物去除潜力,更低温度下(-3~5℃),西伯利亚鸢尾适应性、根际脲酶和磷酸酶活性较高。连续7个月的实际污水处理效果验证了景观型人工湿地处理该区域散户农村生活污水的适用性,对该类地区农村生活污水处理具指导意义和推广价值。

川康边(川西北、康北)根据地的历史地位

川西北、川康边、康北根据地是长征中由三大主力红军共同打造的革命根据地;这三块根据地,地域相连(部分重叠)、创建时间相续、地理环境相似、经济发展水平相近,可视为一个整体进行研究;一路转战的各路红军,在这里严酷自然环境的掩护下和彝、藏、羌族群众的热情帮助下,得到宝贵的休整之机;中共中央及其高级将领们也得以在这里相对从容地探索长征的目的地和中国革命的发展方向;中共中央和张国焘关于实行“北上”还是“南下”战略的是非,在经营这一根据地的斗争实践中得到检验;肩负拯救中华民族危亡重任的中国共产党和中国工农红军,从这里再出发,齐聚西北,不仅赢得长征的最终胜利,而且掀起中国革命的新高潮。