南阳油田东庄次凹核桃园组烃源岩热演化史模拟研究

A Study of Source Rock Thermal Evolution Modeling of Hetaoyuan Formation in Dongzhuang Sag of Nanyang Oilfield

在对南阳油田东庄次凹烃源岩评价和一维、二维地质建模研究的基础上,利用IES盆地模拟软件对东庄油田的南69井、南77井、东9井和东10井以及过东庄次凹的一条二维测线L450-612.5进行了烃源岩热演化史模拟研究.模拟结果表明:①东庄次凹核三段和核二段烃源岩主体处于生油窗内,镜质体反射率Ro介于0.5%～0.8%间,现今生油门限深度约为1 920 m,门限温度约为87°C;②二维烃源岩热演化模拟显示,廖庄组开始沉积时(距今大约27 Ma),东庄次凹核三段Ro达到0.5%,现今Ro为0.7%～0.8%,处于中等成熟阶段早期;核二段距今约20 Ma时,Ro达到0.5%,现今Ro为0.60%～0.65%,处于低成熟阶段;核一段至今仍未达到生油门限;③在距今27 Ma时,二维测线L450-612.5的成熟度和温度模拟剖面显示,油气开始生成时的门限深度为2 000 m,门限温度为93°C,大于现今的门限深度和门限温度.

Based on the evaluation of source rock organic richness,type and maturity,and reconstruction of geological models for 1D and 2D thermal modeling,the sourcerock thermal evolution history of four wells (N69,N77,D9 and D10 wells) and a across section of seismic line 450—612.5 in the Dongzhuang Sag were modeled using IES PetroMod software.The model results indicate that①the E h _3 Layer and most part of E h _2 Layer of the source rocks in Dongzhuang Sag reached oil generative window and the R _o ranged from 0.5% —0.8%.The depth of oil generative threshold of present day is about 1920 meters,and the temperature is about 87 °C in the sag;②2D thermal evolution modeling of the across section showes that the R _o of E h _3 Layer reached 0.5% at about 27 Ma and the present-day R _o reached 0.7%—0.8%,which suggestes that the source rocks in Dongzhuang Sag are in the earlier middle-maturity at present.While the R _o value of E h _2 Layer reached 0.5% at about 20 Ma and the present-day R _o ranged between 0.60%—0.65%,which indicates that the present-day source rocks are in low maturation.E h _1 Layer is immature and R _o value is still less than 0.5% until today;③The maturity and temperature section of line 450—612.5 at 27 Ma reveales that the depth of oil generative threshold was about 2000 meters deep,with its temperature of about 93°C ,higher than the present day′s.