戈布斯坦地区C块地层水化学特征与油气成藏关系

Chemical Characteristics of Formation Water and Hydrocarbon Accumulation in Block C of Gobustan,Azerbaijan

由于油气成藏条件上的差异性以及水文地质条件的不同,造成了阿塞拜疆共和国戈布斯坦地区C块作业区内的5个含油气构造各自具有相对独立的水化学体系。研究认为,Solakhay构造BalaⅦ组的地层水化学特征和油气地球化学特征反映出该油气藏为一个残余油气藏,其气顶天然气为原油生物降解成因。西Duvanny构造SurakhanyⅤ-Ⅶ砂组的CaCl2型水(按苏林分类)则反映了其定容气藏(一砂一藏)的特征,具有较好的封闭条件。Kyanizadag构造BalakhanyⅦ砂组高矿化度地层水及CaCl2型水表明该构造具有较好的保存条件。通过对Dashgil构造BalakhanyⅦ砂组NaHCO3型水的成因分析,认为NaHCO3型水的形成主要是由于原油生物降解影响造成的。另外,Dashgil构造南翼Das53井区出现的Na2SO4型水,分析认为具有混合成因水的特征,可能是不同时期流体聚集混合的结果。

There exist relatively individual formation water chemical systems in five petroliferous structures in Block C of Gobustan, Azerbaijan for reasons of differences in hydrocarbon accumulation and hydrogeologic conditions. The study shows that Solakhay structural reservoir of Bala Ⅶ formation is suggested to be a residual reservoir with a gas cap of crude biodegradation origin, according to its formation water chemical characteristic and petroleum geochemic.al feature. The chloride-calcium type water from Surakhany Ⅴ-Ⅶ sand layers in West Duvanny structural reservoir reflects that it is a constant-volume gas reservoir with good seal conditions. The high-salinity water and chloride-calcium type water from Balakhany Ⅶ sand layer in Kyanizadag structural reservoir indicate that it is in good conservation condition. The sodium-bicarbonate type water from Balaknany Ⅶ sand layer in Dashgil structural reservoir is formed by crude biodegradation. And the sodium-sulfate type water found in Wellblock Das53 of the south side of Dashgil structural reservoir belongs to mixed genetic water possibly resulted from fluid accumulation and mixing in different periods.