风城超稠油双水平井蒸汽辅助重力泄油开发试验

摘要

The super heavy oil in Fengcheng field is characterized by high viscosity, shallow burial depth, difficult of eonventional exploitatiun and low degree of recovery'. In 2008 and 2009, Wellblock Zhong-32 and Zhong-37 were successively as pilot areas in this field for SAGD process by pair of horizontal wells, integrated with the foreign experienees from analogous reservoirs exploitation and the characteris- tics of this reservoir. However, the unreasonable circulating preheating pressure differential control and string structure in real production caused poor connectivity in horizontal sections, low producing degree, easy steam breakthrough and high fluctuation of production. In this paper, 3D geologic modeling for studying the reservoir petrophysical property and barrier distribution is adopted to improve effect of SAGD development, finely recognize the geological tbatures of resm'voir. Furthermore, the key t~gulation technology for the SAGD circulafng pre- heating stage is confirmed to be the pressure differential controlling. The dynamic balance among the liquid-withdrawing capacity of steam chamber, the steam injection and recovery percent is the guidance tor production stage by SAGD process. So, such a SAGD technology for regulation and control is suitable for the whole pilot area.%风城油田超稠油黏度大、埋藏浅，常规开采难度大，采出程度低。借鉴国外类似油藏开发的经验，结合油藏自身特点，运用双水平井蒸汽辅助重力泄油（SAGD）开发技术，建立了重32、重37井区SAGD试验区。在实际生产中由于循环预热压差控制和管柱结构不合理，导致水平段连通性差，动用程度低，极易汽窜，生产波动大。为了提高开发效果，以强化精细地质研究为前提，应用三维地质建模研究储集层物性及隔层空间分布，精细认识油藏地质特点；对SAGD循环预热阶段进行总结梳理，认识到预热阶段核心调控技术是压差控制；在SAGD生产阶段，保证汽腔供液能力、注汽和采出三者的动态平衡是关键，对整个试验区不断探索、分析和总结，逐渐形成一套成熟的SAGD开发调控技术。