应用盆地模拟技术评价西藏伦坡拉盆地油气资源潜力

Application of basin simulation technology on the assessment of hydrocarbon resources potential of the Lunpola Basin in Tibet

伦坡拉盆地是西藏地区唯一取得工业油流的含油气盆地,由于地质条件复杂,油质偏稠,导致油气勘探进展缓慢。为了明确盆地油气资源潜力,有效指导下一步勘探方向,文章结合新钻探及地震资料,运用盆地模拟方法开展埋藏史、热史及生烃史研究,计算了盆地古近系生烃量和资源量。结果表明伦坡拉盆地古近系生烃量为49.80×10~8 t,资源量为1.507×10~8 t。其中以蒋日阿错为最大生烃中心,生烃量20.93×10~8 t,资源量1.05×10~8 t,江加错和爬错北部为次重要生烃中心,生烃量分别为8.83×10~8 t和14.76×10~8 t,资源量分别为0.41×10~8 t及0.71×10~8 t。从模拟结果可知,蒋日阿错洼陷、江加错洼陷资源丰度相对较高,为油气资源富集有利区,爬错洼陷由于烃源和圈闭条件较差,目前仅发现罗玛迪库构造圈闭,资源丰度较低。应用盆地模拟明确了伦坡拉盆地油气资源构成和油气资源分布有利区带,为下一步勘探指明了方向。

The Lunpola Basin is the only petroliferous basin in Tibet that has obtained industrial oil flows.Due to the complicated geologic conditions and the oil is relatively thick,the progress of its oil-gas exploration is slow.In order to analyze the potentiality of hydrocarbon resources and effectively guide the oil exploration in the future,the basin simulation technology was applied to study geologic history,thermal history,hydrocarbon-generation history and the resources amount of Paleogene in this basin was calculated by combining new drilling and seismic data.The results show that the hydrocarbon-generation quantity and oil-gas resource amount of Paleogene in the Lunpola Basin are 49.80×108 t and 1.507×108 t respectively.The Jiangriacuo Sag is the largest hydrocarbon-generation center in this basin,which has hydrocarbon-generation quantity as 20.93×108 t and the oil and gas resource amount as 1.05×108 t.The Jiangjiacuo Sag and the north part of the Pacuo Sag are the second most important hydrocarbon generation centers,which have hydrocarbon generation quantity as 8.83×108 t and 14.76×108 t,and the resources amount as 0.41×108 t and 0.71×108 t respectively.From the simulation results,considering the hydrocarbongeneration intensity,the Jiangriacuo Sag and the Jiangjiacuo Sag are the favorable areas for hydrocarbon accumulation.Because of the poor hydrocarbon source and trap conditions,only the Luomadiku structural trap has been found,and the resource abundance in the Pacuo Sag is low.By using basin simulation technology,the hydrocarbon resources composition and the favorable zones of hydrocarbon resources distribution in the Lumpola Basin are defined,which points out the direction for further exploration.