盐城天然气藏地质特征及其勘探意义

盐城天然气藏的发现经历曲折 ,给人启示。从天然气藏的基本地化特征、天然气及其源岩类型、天然气成熟度等分析 ,盐城天然气藏为“古生新储”型晚期成藏的天然气藏。该气藏发现的意义在于为苏北地区“古生新储”、“古生中储”型天然气藏的勘探提供了地质模型 ,也为扬子中古生界海相地层的勘探提供了借鉴。

盐城天然气藏的发现及其战略意义

为了进一步完善盐城天然气成藏条件及成藏机理研究 ,进而拓宽天然气勘探思路 ,从盐城天然气藏的基本地化特征、天然气及其源岩类型、天然气成熟度等资料的分析入手 ,研究结果表明盐城天然气为“古生新储”型晚期成藏的天然气藏 .该气藏发现为苏北地区“古生新储”“古生中储”天然气藏的勘探提供了地质模型 ,并对扬子中古生界海相地层的勘探很有借鉴作用 .

松辽盆地徐家围子断陷深层天然气成因类型及各种成因气贡献

徐家围子断陷深层首次发现以腐泥型气为主的有机成因天然气,不同地区深层天然气成因类型及各种成因气的贡献成为研究重点。采集徐家围子断陷29口井35件深层天然气和26口井33件深层烃源岩样品,采用组分碳同位素和轻烃指纹色谱方法分析天然气和烃源岩样品,实验研究认为深层天然气主要为腐殖型气、腐泥型气、有机深源气3种成因组成的混合气,无机成因烷烃气的贡献较小。首次提出了多种有机成因类型天然气贡献定量测试方法并进行了实验验证,采用天然气甲烷碳同位素、乙烷碳同位素和甲基环己烷指数、环己烷指数、脂烃族参数5个成因类型指标,确定了腐殖型气、腐泥型气、有机深源气的5个成因类型指标端元值,利用天然气的混合配比性建立成因类型指标地球化学模型,采用非线性数学模拟方法建立计算模板,首次定量测试了徐家围子断陷深层天然气样品中3种有机成因气的定量贡献。实验结果表明,徐家围子断陷深层天然气除昌德气藏芳深1井、芳深2井有机深源气贡献为81%外,其他井的腐殖型气、腐泥型气和有机深源气平均贡献分别为62.45%、25.51%、12.02%;不同地区及井段的腐殖型气、腐泥型气和有机深源气贡献有差别,升平—汪家屯地区平均贡献分别为61.63%、20.94%、17.29%,昌德地区平均贡献分别为73.74%、14.48%、11.77%,兴城—徐东地区及断陷中东部平均贡献分别为51.98%、40.99%、7.01%。从断陷北部到中部即从升平—汪家屯、昌德到兴城—徐东地区有机深源气贡献减少、腐泥型气贡献增大,部分井段腐泥型气贡献超过43%且为主要贡献,个别井段腐泥型气贡献最大达74%,与断陷中东部烃源岩Ⅱ型有机质相对发育及断陷地层地质特征相吻合,呈现主要来源于下伏气源岩和天然气藏以垂向运移为主、侧向运移为辅的源岩控型成藏特征。

板桥凹陷深层天然气气源对比与成因分析

板桥凹陷深层及奥陶系潜山均钻遇乙烷以上具异常重碳同位素的天然气。使用轻烃族组成、C7轻烃组成、环烷指数及苯、甲苯碳同位素证实 ,气源主要为板桥凹陷下第三系偏腐殖型烃源岩。进而从石炭—二叠系地层分布和二次成烃条件等方面 ,进一步否定了煤成气作为烃源的可能性。应用 δ13C2 与 δ13C2 -1相关关系图解判断 ,板桥凹陷异常重碳同位素天然气可以分为成熟阶段早期和中期腐殖型天然气、高成熟阶段早期腐殖型天然气和过成熟阶段天然气。根据天然气碳同位素特征 ,结合其它研究成果 。

Reactions Between Humic Acid Solutions and Excessive ClO_2 or Cl_2

Reactions between humic acid solutions and excessive ClO2 or Cl2 have been investigated. Under various experimental conditions, the removal efficiency of TOC, UV254and A410 from humic acid solutions were examined. The relationship between the removal efficiency and the consumption of ClO2 or Cl2 was discussed. The results showed that the maximum demand of ClO2 was 2.19 mg/mg TOC for the humic acid solution under the experimental conditions, and that of ClO2 was 1.88 mg/mg TOC. The variation tendency of ClO2 consumption was similar to that of Cl2. TOC of humic acid solutions decreased 15.2% and 15.6% after the reaction with ClO2 or Cl2 respectively. Under the experimental conditions, 21.4% of unsaturated bonds and 52.8% of humic acid color were removed by ClO2 in 168 h. As for Cl2, removal efficiency of unsaturated bonds and humic acid color were 16.8% and 41.7% respectively. Larger molecules from humic acid were oxidized to smaller molecules by ClO2 and Cl2. Higher oxidation potential of ClO2 than that of Cl2 was also indicated by variation of UV254/A410 ratios. The similar tendency, that exhibited faster variation in the initial 24 h, existed for all the research factors.