论文部分内容阅读
喜山期的干气对塔里木盆地塔中Ⅰ号坡折带古油藏气侵作用是导致油气分馏形成凝析气藏的重要原因,前人关于塔中地区气侵的研究多为定性描述,而定量化的研究较少。以处于塔中Ⅰ号坡折带内带的塔中83井区为研究对象,剖析研究区的成藏地质条件,总结其油气性质、组分特征,进而开展原油样品正构烷烃定量测试,计算研究区不同油气藏的原油正构烷烃损失率Q,对其气侵强度进行了定量化评价。正构烷烃损失率Q的计算结果表明,研究区油气藏都遭受了不同程度气侵(Q变化范围为12%～86%),气侵强度在平面上表现出由北西向南东逐渐减小,剖面上由下向上逐渐变小,同时,气侵导致油气性质改变,原油中的低碳数正构烷烃溶于气相,脱离油相形成与凝析油伴生的高含腊量原油,证实了沿塔中82走滑断裂和塔中Ⅰ号断裂交汇部位充注的高—过成熟度干气对研究区油气藏的气侵作用,为该区油气成藏研究提供了定量证据。
The dry gas from the Himalayan period was the main reason for the gas-oil fractionation to form condensate gas reservoirs. The previous studies on gas intrusion in the Tazhong area mostly described the gas, The quantitative research is less. Taking Tazhong 83 well in Tazhong Ⅰ slope break zone as the research object, the hydrocarbon accumulation geological conditions in the study area were analyzed, and their oil and gas properties and component characteristics were summarized. The quantitative test of n-alkanes in crude oil samples was carried out. The losses of n-paraffins from different oil and gas reservoirs in the study area Q were quantitatively evaluated. Calculation results of n-paraffins loss rate Q show that the oil and gas reservoirs in the study area all suffered from gas invasion in varying degrees (Q ranged from 12% to 86%), and their gas invasion intensity decreased gradually from northwest to southeast in the plane , The cross section becomes smaller gradually from bottom to top, meanwhile, the gas invasion leads to the change of the nature of oil and gas. The low-carbon n-alkanes in crude oil dissolves in the gas phase and leaves the oil phase to form crude oil with high content of wax, which is associated with condensate oil. The gas-intrusion into the reservoirs in the study area along the high-maturity dry-gas charge at the junction of strike-slip fault 82 and fault Tazhong Ⅰ in the Tazhong area provides quantitative evidence for the study of hydrocarbon accumulation in this area.