水平井轨迹偏移对蒸汽辅助重力泄油生产的影响

The Impact of Horizontal Well Trajectory Offset on Production by SAGD Process

以克拉玛依风城油田重32井区典型储集层物性和流体参数为基础,分析总结双水平井蒸汽辅助重力泄油(SAGD)实钻轨迹形态特征,建立表征水平段水平偏移、垂向偏移以及水平与垂向同时偏移不同偏移程度的油藏数值模型,开展SAGD生产动态预测与效果对比。模拟结果表明,井组轨迹水平偏移和垂向偏移均导致峰值产油量、采出程度和累计油汽比下降,其中,垂向偏移对SAGD生产效果的影响较大。水平井轨迹局部垂距减小,易造成水平段局部窜通,钻井过程中应避免水平段"脚跟"及"脚尖"处同时垂距变小。水平段水平与垂向同时偏移时,其生产负面影响远大于水平偏移与垂向偏移简单相加,双向偏移量越大,生产效果越差。

Based on he typical petrophysical properties and fluid parameters in Wellblock-Z32 in Fengeheng oilfield of Junggar basin, the real trajectories of dual-horizontal well pairs by steam-assisted gravity drainage （SAGD） proses are analyzed and the numerical simulation models for characterization of tile lateral and vertical offset in horizontal interval as well as simuhaneous lateral-vertical offsets are devel- oped, and the SAGD production pertormance prediction and response correlation are conducted. The simulation resuhs show that the later- al offset amt vertical offset may cause reductions of the peak oil rate, oil recovery factor and oil steam ratio, of which the vertical offset has more impact on tile SAGD response. The local vertical offset distance reduction may give rise to partial steam breakthrough in horizontal in- terval, therefore, during drilling process, the simultaneous reduction of vertical offset distance in the two ends of horizontal interval should be avoided, because when taking simultaneous offsets, the adverse impact on the production is much more than the simply adding of the im- pact of lateral offset and vertical offset, and the more bi-directional offset, the poorer the SAGD performance.