CO2-induced dissolution of low permeability carbonates. Part II: Numerical modeling of experiments     

《Advances in water resources》2013

We used the 3D continuum-scale reactive transport models to simulate eight core flood experiments for two different carbonate rocks. In these experiments the core samples were reacted with brines equilibrated with pCO₂ = 3, 2, 1, 0.5 MPa (Smith et al., 2013 [27]). The carbonate rocks were from specific Marly dolostone and Vuggy limestone flow units at the IEAGHG Weyburn-Midale CO₂ Monitoring and Storage Project in south-eastern Saskatchewan, Canada. Initial model porosity, permeability, mineral, and surface area distributions were constructed from micro tomography and microscopy characterization data. We constrained model reaction kinetics and porosity–permeability equations with the experimental data. The experimental data included time-dependent solution chemistry and differential pressure measured across the core, and the initial and final pore space and mineral distribution. Calibration of the model with the experimental data allowed investigation of effects of carbonate reactivity, flow velocity, effective permeability, and time on the development and consequences of stable and unstable dissolution fronts.The continuum scale model captured the evolution of distinct dissolution fronts that developed as a consequence of carbonate mineral dissolution and pore scale transport properties. The results show that initial heterogeneity and porosity contrast control the development of the dissolution fronts in these highly reactive systems. This finding is consistent with linear stability analysis and the known positive feedback between mineral dissolution and fluid flow in carbonate formations. Differences in the carbonate kinetic drivers resulting from the range of pCO₂ used in the experiments and the different proportions of more reactive calcite and less reactive dolomite contributed to the development of new pore space, but not to the type of dissolution fronts observed for the two different rock types. The development of the dissolution front was much more dependent on the physical heterogeneity of the carbonate rock. The observed stable dissolution fronts with small but visible dissolution fingers were a consequence of the clustering of a small percentage of larger pores in an otherwise homogeneous Marly dolostone. The observed wormholes in the heterogeneous Vuggy limestone initiated and developed in areas of greater porosity and permeability contrast, following pre-existing preferential flow paths.Model calibration of core flood experiments is one way to specifically constrain parameter input used for specific sites for larger scale simulations. Calibration of the governing rate equations and constants for Vuggy limestones showed that dissolution rate constants reasonably agree with published values. However the calcite dissolution rate constants fitted to the Marly dolostone experiments are much lower than those suggested by literature. The differences in fitted calcite rate constants between the two rock types reflect uncertainty associated with measured reactive surface area and appropriately scaling heterogeneous distribution of less abundant reactive minerals. Calibration of the power-law based porosity–permeability equations was sensitive to the overall heterogeneity of the cores. Stable dissolution fronts of the more homogeneous Marly dolostone could be fit with the exponent n = 3 consistent with the traditional Kozeny–Carman equation developed for porous sandstones. More impermeable and heterogeneous cores required larger n values (n = 6–8).  相似文献   

SYZX75型绳索取心液动锤在肃北德勒诺尔铁矿区的应用          下载免费PDF全文

罗冠平 《探矿工程》2012,39(1):47-49,56

介绍了SYZX75型绳索取心液动锤在甘肃省肃北县德勒诺尔铁矿区坚硬、破碎地层中的应用情况,总结了该钻具在斜孔施工中的经验。实践表明,使用SYZX75型绳索取心液动锤,大幅度提高了回次进尺和钻进效率;有效克服了破碎地层的岩心堵塞,提高了破碎地层岩心采取率;有助于斜孔施工中的孔斜度控制。  相似文献   

Study on the Recovery of Erosion Quantity of Unconformities of Paleogene-Neogene in Bohai Sea Area     

LI Rufeng  ZHANG Gangxiong  RUAN Xiaofei 《地质论评》2012,58(3)

应用盆地波动过程分析方法,对渤海海域9个不同坳陷内的18口典型井古近系和新近系进行了沉积—剥蚀过程分析,分解出了760Ma、220Ma、70Ma和30Ma四个低频波动周期,以及18Ma、8Ma和2Ma三个高频波动周期.通过分析反映"组"、"段"级别的、以18Ma和8Ma为周期的波动曲线特征,预测了孔店期—沙河街期沉积—剥蚀过程;系统地计算出了古近纪—新近纪地层中主要不整合的剥蚀量,确定了与油气成藏密切相关的孔店组末期、东营组末期和馆陶组末期地层剥蚀厚度分别为:0～516m、0 ～213m和0～682m.通过波动曲线特征对比分析,确定了研究区构造转换带分别是孔店期位于渤中、沙河街期和东营期位于BZ13-1-2井区和LD10-1-1井区、馆陶期位于LD10-1-1井区、明化镇期位于BZ3-1-3D井区;定量地恢复了与油气运聚密切相关的孔店晚期、东营晚期和馆陶晚期不整合剥蚀量平面分布,再现了关键时期沉降沉积区和隆起剥蚀区区域分布规律.上述认识对于深入研究渤海海域古近系—新近系油气分布规律,开拓沙河街组及其以下层系油气勘探新领域具有重要意义.  相似文献   

浅述甘肃省生态环境保护与恢复的对策和建议          下载免费PDF全文

余志山  付东林 《甘肃地质》2012,(3):11-14

针对甘肃省典型区域与其在城镇化进程中的主要地质环境问题之间的协调性的宏观特点,从原自然生态环境的恢复与保护、城市区人工生态的建设与保护、黄土区生态环境的恢复与保护、陇南地区生态环境的恢复与保护及未来整个陇东能源基地建设中生态环境恢复与保护所面临的问题等方面,浅述甘肃省生态环境保护与恢复的一般性对策和建议。  相似文献   

Environmental effects of the MV Rena shipwreck: cross-disciplinary investigations of oil and debris impacts on a coastal ecosystem     

DR Schiel  PM Ross  CN Battershill 《新西兰海洋与淡水研究杂志》2016,50(1):1-9

ABSTRACT

The 2011 wreck of the MV Rena off the northeast coast of New Zealand, and subsequent impacts, has been called New Zealand's worst ever maritime environmental disaster. It is certainly one of the world's most complex as it involved a pollutant combination of oil and dangerous goods debris in a dynamic oceanic environment adjacent to a pristine coastline. Heavy fuel oil, shipping containers loaded with cargo, and a wide range of wreck debris and contaminants were spread along hundreds of kilometres of coastline of the Bay of Plenty. Much of this landed on sandy beaches and rocky shores. Broken containers released often toxic substances, and the wreck itself slid down the pinnacle of the wreck site at Astrolabe Reef (Otaiti). The reef remains heavily contaminated, with substantial remnants of the ship and its cargo present, and chemical effects still evident in some species. Here we present the background and timeline of events that unfolded after the grounding. The following articles contain the results of the ensuing chemical, toxicological and ecological studies of contamination and environmental recovery. At the time of writing, numerous legacy issues remain.  相似文献   

新型卤水补给采集井AK1井施工工艺          下载免费PDF全文

隆东  王升  林修阔  胡汉月  刘志强  岳刚 《探矿工程》2016,43(8):34-38

AK1井是在土耳其Beypazari天然碱矿老矿区选址并钻进形成的新型卤水补给采集井。该井采用中国地质科学院勘探技术研究所自行研制的SDC-1500型车载钻机钻进施工,并下入带有悬挂器的特殊套管串成井。该井创新性地使用负压抽采模式采取地下卤水。其单井出卤量3倍于生产井,有效缓解了矿加工厂卤水供应量不足的情况,提高了生产效率。  相似文献   

澳大利亚煤层气开发工艺技术     

赵兴龙  汤达祯  陶树  陈贞龙  吕玉民  蔡佳丽 《中国煤炭地质》2010,(9):26-31

参考当前国内外在煤层气开发方面的相关研究成果,对澳大利亚现今主要的煤层气开发工艺技术,包括钻采工艺技术和煤层气开采技术进行了重点重点调研,以期能够给予我国煤层气产业发展起到启示作用。研究表明:澳大利亚目前最主要的钻井类型是中等半径钻井,普遍运用欠平衡钻井工艺,其煤层气开采技术因地制宜,采用有针对性的工艺方法。对于与我国煤层气地质条件相似的区域,其煤层气开发技术值得我们借鉴。  相似文献   

对目前煤炭资源勘查与开发利用中存在的一些问题的思考     

高洪烈 《中国煤炭地质》2010,(11):67-69

煤炭资源勘查和开发利用中,存在着一些值得思考与探讨的问题,如资源储量划分、勘查区境界的依据、资源分类与勘查程度的关系、回采率问题、共伴生矿床的勘查、煤层气勘查与瓦斯抽放、水文地质工程地质及开采技术条件勘查、采矿废弃物资源化、基础性地质工作的管理等。针对上述问题,结合煤炭资源勘查实践,提出了相应的建议。  相似文献   

二元气体等温吸附实验及其对煤层甲烷开发的意义   总被引：11，自引：0，他引：11  

唐书恒  汤达祯杨起 《地球科学》2004,29(2):219-223

分别进行了CH₄-CO₂和CH₄-N₂二元混合气体的等温吸附实验, 并且分析了二元气体在吸附过程中各组分浓度的变化规律.结果表明, 在CH₄-N₂二元气体的吸附过程中, 吸附相中CH₄组分的相对浓度逐渐增加, N₂组分的相对浓度逐渐减少.在CO₂-CH₄二元气体的吸附过程中, 吸附相中CO₂组分的相对浓度逐渐增加, CH₄组分的相对浓度逐渐减少.实验结果证实了CO₂在与CH₄的竞争吸附中占据优势, 而N₂在与CH₄的竞争吸附中处于劣势.注入CO₂比注入N₂可以更有效地置换或驱替煤层甲烷, 提高煤层甲烷的采收率.   相似文献   

论硫铁矿烧渣的再生与利用   总被引：8，自引：0，他引：8  

刘闯  蒋其胜  王志勇  高静 《安徽地质》2000,(4)

介绍硫铁矿烧渣的一般特征,再生利用现状和存在问题,提出合理利用和保护资源,维护生态环境。  相似文献