超稠油油藏EBIP厚度变化模式对SAGD的影响

SAGD技术是一种非常具有潜力的稠油开发方式，已在超稠油/油砂开发中取得了良好效果。由于储层沉积原因，SAGD水平井段对应的EBIP有效储层厚度通常会发生变化，使得SAGD井组开发效果差异明显。为了明确EBIP厚度沿水平井段变化对SAGD生产的影响，以加拿大Long Lake油田地质特征为基础，构建了3种典型EBIP厚度变化模式，建立了SAGD数值模拟机理模型，分析讨论了沿程EBIP变化模式和厚度差对SAGD蒸汽腔突破、日产油、累计汽油比和采出程度的影响，明确了EBIP厚度变化对SAGD生产影响的界限。研究表明，在储层总厚度相同下，阶梯状EBIP变化模式峰值产油速度和采出程度最低，其他两种方式生产特征相近；阶梯状EBIP模式下，厚度差64 m为优，4<厚度差<10 m为良，厚度差>10 m为差；两厚一薄和两薄一厚EBIP模式，厚度差<7 m为优，厚度差>7 m对SAGD生产影响大。

Influence of EBIP Thickness Variation Modes on SAGD Production Characteristics in Super Heavy Oil Reservoirs

Steam assisted gravity drainage (SAGD) is a promising heavy oil development method, which has achieved good results in super heavy oil/oil sand development. Due to reservoir sedimentation, the effective reservoir thickness (EBIP) along the SAGD horizontal well section will change, which makes the development effect of SAGD well group significantly different. In order to make clear the influence of EBIP changing along horizontal well section to SAGD production, based on the geological characteristics of Long Lake oilfield in Canada, 3 typical EBIP thickness change modes are constructed. Subsequently, the SAGD numerical simulation mechanism model is established, and SAGD steam chamber breakthrough, daily oil production, cumulative gasoline ratio and recovery degree influenced by the EBIP change modes and thickness difference are analyzed and discussed. Finally, limits of on SAGD production which are influenced by the EBIP thickness are built. The results show that under the same total thickness of reservoir, the peak oil production speed and recovery degree of stepped EBIP change mode are the lowest, and the production characteristics of the other two modes are similar. Under stepped EBIP mode, the thickness difference 6 4 m is excellent, the thickness difference of 4～10 m is good, and the thickness difference >10 m is poor. Under two thick-one thin and two thin-one thick EBIP mode, the thickness difference <7 m is excellent, and the thickness difference >7 m has a great impact on SAGD production.