楚—萨雷苏盆地Marsel探区下石炭统烃源岩生排烃特征及有利区预测

Hydrocarbon generation and expulsion characteristics of Lower Carboniferous source rocks and favorable area prediction in Marsel Area,Chu-Sarysu Basin

以楚—萨雷苏盆地Marsel探区下石炭统烃源岩为研究对象,基于岩石热解实验结果,采用生烃潜力法建立生排烃模型,分析Marsel探区下石炭统烃源岩生排烃特征,评估油气资源潜力,结合沉积相平面展布特征预测有利勘探区。结果表明:Marsel探区下石炭统烃源岩分布广、厚度大,有机质丰度较高,有机质类型主要为Ⅲ型,处于成熟—高成熟演化阶段。生烃门限和排烃门限对应的镜质体反射率分别为0.46%和0.68%,生烃高峰和排烃高峰对应的镜质体反射率分别为1.22%和1.48%。谢尔普霍夫阶烃源岩累计生烃量为1.623 1×10^(10)t,排烃量为1.474 6×10^(10)t,残留烃量为1.485 0×10^(9) t;维宪阶烃源岩累计生烃量为4.261 9×10^(10)t,排烃量为3.935 0×10^(10)t,残留烃量为3.269 0×10^(9)t。生烃中心、排烃中心和残留烃中心在平面位置上具有一致性。下石炭统天然气可采资源量为(6.79-15.08)×10m^(3),平均为10.56×10m^(3)。下石炭统油气显示井主要分布于探区北部,探区西北部烃源岩排烃强度较高,是进一步勘探的有利区域。该结果为Marsel探区下石炭统天然气勘探开发提供依据。

Taking the Lower Carboniferous source rocks in Marsel Area of Chu-Sarysu Basin as the research object,the hydrocarbon generation and expulsion model is established by means of hydrocarbon generation potential method based on the results of rock pyrolysis,this paper analyzes the hydrocarbon generation and expulsion characteristics of Lower Carboniferous source rocks,evaluates the potential of oil and gas resources,and predicts the favorable exploration area in combination with the plane distribution of sedimentary facies in Marsel Area.The results show that the Lower Carboniferous source rocks in Marsel Area are widely distributed,thick,and high abundance in organic matter.The type of organic matter is mainly type Ⅲ kerogen,which are in the mature-high mature stage.The R_(0) values corresponding to hydrocarbon generation threshold and hydrocarbon expulsion threshold are 0.46% and 0.68%,and the hydrocarbon generation peak and hydrocarbon expulsion peak are 1.22% and 1.48%,respectively.The cumulative amount of hydrocarbon generation and of C_(1)sr source rocks is 1.623 1 ×10^(10),hydrocarbon expulsion amount is 1.474 6 ×10^(10),and residual hydrocarbon amount is 1.485 0× 10^(9) t.The C_(1)v source rocks are 4.261 9 × 10^(10),3.935 0 ×10^(10) and 3.269 0×10^(9) t,respectively.The center of hydrocarbon generation,hydrocarbon expulsion and residual hydrocarbon are consistent in plane position.The recoverable natural gas resource of Lower Carboniferous ranges is(6.79-15.08) × 10^(12)m^(3),with an average of 10.56 × 10^(12)m^(3).The oil and gas display wells discovered in the Lower Carboniferous are mainly distributed in the north of the area.The northwest of the area has high hydrocarbon expulsion intensity of the source rock,which is a favorable area for further exploration.This result provides a basis for the exploration and development of Lower Carboniferous natural gas in Marsel Area.