长湖油田油砂SAGD数值模拟及应用

SAGD numerical simulation and application of oil sands in Long Lake Oilfield

为了准确高效地认识加拿大长湖油田剩余油分布,针对有100多个井对、10多年生产历史的油砂油田开展数值模拟敏感性分析和历史拟合,分析油砂开发物性参数和操作参数对开发效果的影响,对历史拟合过程中可能遇到的问题提出解决方法。模型敏感性分析结果显示1)静态参数中初始含油饱和度和储层厚度对累产油的影响最大,其次是孔隙度和渗透率;2)当含油饱和度或渗透率过低时,蒸汽腔会偏离典型Butler蒸汽腔发育形态,产量曲线形态也会相应改变,实际油田生产曲线也表现出同样的特征。历史拟合结果显示1)各地下泄油区剩余油分布差异大,泄油区内部水平井延程剩余油分布不均,部分泄油区井间剩余油富集,具备加密潜力;2)历史拟合中常出现局部憋压、模型运算速度慢的情况,可通过注汽井间隔设置定注汽量和定注汽压力注入解决;3)当SAGD(蒸汽辅助重力泄油)生产井对中间的单支水平加密井的初始钻遇地层温度达到30℃以上时,通过1个月的循环预热该加密井可与周围注汽井建立有效注采关系并顺利投产。

To evaluate the Long Lake Oilfield residual oil distribution correctly and effectively,numerical simulation sensitivity analysis and history match is conducted on oil sand field with more than 100 well pairs and more than ten years of production.Analyze the influence of oil sand reservoir parameters and operation parameters to development effect and problems that may be encountered while history match and give solutions.Simulation sensitivity analysis shows:1)Among static parameters,initial oil saturation and reservoir thickness have the biggest impact to cumulative oil,porosity and permeability have less impact but still significant;2)If the initial oil santuration or the permeability is too low,the shape of steam chamber deviates from the ideal Butler shape and the production profile changes accordingly;Real well production curves also show similar characteristics.History match result shows:1)The residual oil differs between drainage areas and along the direction of wellbore;There are residual oil between two production wells,which shows potential for infills;2)Setting injector conditions by pressure and steam rate one after the other can effectively simulate the steam cross flow between nearby drainage areas and avoid pressure build up due to excess steam injection,which speeds up the simulation;3)As long as the temperature drilled along the infill well is higher than 30℃,it can build communication with nearby steam injectors after 1 month of steam circulation and start production.