天然气中丁烷地球化学特征及应用

发布时间：2018-07-05 15:47

  本文选题：丁烷地球化学特征 + iC_/nC_　； 参考：《天然气地球科学》2017年04期

【摘要】：在分析内因(有机质类型、有机质成熟度)与外因(生物降解、运移)对天然气中丁烷地球化学特征影响的基础上,探讨了丁烷在天然气研究中的应用。首先明确了内因、外因对丁烷地球化学特征的影响:腐殖型有机质生成的煤型气iC_4/nC_4值、δ~(13)C_4值均高于腐泥型有机质生成的油型气;iC_4/nC_4值随成熟度增加而降低,且在成熟阶段快速降低、进入高成熟阶段后缓慢降低;微生物降解会使得天然气中iC_4/nC_4值增大,且降解作用越强iC_4/nC_4值越大。而目前有关运移是否会影响iC_4/nC_4值及如何影响iC_4/nC_4值还存在较大争议。发现丁烷在天然气生物降解、天然气成因、天然气成熟度等研究中都有较好的应用:iC_4/nC_4值能有效判识天然气是否发生生物降解,生物降解气iC_4/nC_4值大于2、普遍大于3,iC_4/nC_4值大于3可以判定天然气发生生物降解,未降解气iC_4/nC_4值小于3、普遍小于2,iC_4/nC_4值小于2可以判定天然气未发生生物降解;iC_4/nC_4值、δ~(13)C_4值均能有效判识受外因影响较小天然气的成因,其判别标准分别为油型气iC_4/nC_4值小于0.8、煤型气iC_4/nC_4值大于0.8与油型气δ~(13)C_4值小于-26‰、煤型气δ~(13)C_4值大于-26‰;iC_4/nC_4值对天然气成熟度判识也有重要作用。iC_4/nC_4值示踪天然气运移存在多解性,其有效性也明显不如其他指标,应慎重选择其示踪天然气运移。
[Abstract]:Based on the analysis of the effects of internal factors (organic matter type, maturity of organic matter) and external factors (biodegradation, migration) on the geochemical characteristics of butane in natural gas, the application of butane in natural gas is discussed. Firstly, the effects of internal and external factors on the geochemical characteristics of butane are defined: the value of iC4, 未 ~ (13) C4 of coal-type gas generated by humic organic matter is higher than that of oil-type gas produced by sapropelic organic matter, and the value of IGR 4 / nC4 decreases with the increase of maturity, and decreases rapidly in mature stage. The degradation of microorganism will increase the value of 4 / nCstack in natural gas, and the stronger the degradation effect is, the greater the value of iCstack / nC4 is. At present, there is still controversy about whether migration will affect the value of 4 / nCIV and how to affect the value of 4 / nC4. It is found that butane has a good application in the study of natural gas biodegradation, natural gas genesis, natural gas maturity and so on. It can effectively judge whether natural gas is biodegradable or not. Biodegradable gas iC4 / nC4 is greater than 2, and generally greater than 3% nC4 > 3 can be used to determine the biodegradation of natural gas. If the value of the undegraded gas is less than 3, and generally less than 2iC4 / nC4 is less than 2, it can be determined that there is no biodegradation of natural gas at 4 / nC4. The value of 未 ~ (13) C4 can effectively identify the origin of natural gas that is less affected by external causes. The criteria for the determination are as follows: the value of the oil-type gas Che _ (4) / n _ C _ (4) is less than 0.8, the value of the coal type gas is greater than 0.8 and the value of the oil type gas 未 ~ (13) C _ (4) C _ 4 is less than -26 鈥，

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