基于灰色关联法的海上大段合采油田堵水研究

Research on water detection and plugging in offshore large section combined production oilfield based on grey relational analysis

不同于陆地油田,海上油田多采用大井距、大段合采方式开发。进入开发中后期,油田含水上升快、注采关系不明确、产量快速下降,海上测试资料偏少导致常规研究手段难以快速选择堵水目标井和目标层,无法直接套用陆地开发调整经验,大段合采堵水问题亟待解决。本文利用灰色关联方法分析油田高含水期流体参数、储层物性及注采参数对油田产量影响,经数值模拟结合实际数据分析验证各参数对于产量的影响权重,并进行排序,将含水率、产油量、井底流压三个生产指标为堵水选井选层主控因素,建立了一套高含水期大段合采油田找水堵水评价方法。通过渤海Q油田大段合采堵水实践,先导试验井对1井沙二段Ⅰ、Ⅲ油组卡水后,大大降低了大段合采层间干扰,油井产量增加14倍。渤海大段合采老油田开发后期高含水治理调整实践表明,灰色关联法可有效识别出水层位,有助于调剖堵水作业实施。

Different from the land oilfields, offshore oilfields are mostly developed by large well spacing and large section mining methods. In the late stage of oilfield development, the oilfield water cut rises rapidly, the injection-production relationship is not clear, and the production rate declines rapidly. Lack of offshore test data, it is difficult to select the water-blocking target well and layer quickly through conventional research methods, the land development adjustment experience cannot be applied in offshore oilfield. In this paper, the grey correlation method is used to analyze the influence of fluid parameters, reservoir physical properties and injection-production parameters on oilfield production in high water cut period. The value of the parameters is analyzed to verify the weight of each parameter on the production. A set of water detection and plugging technology for large section commingled produced high water cut offshore oilfield is established, which shows that the main controlling factors are water cut, oil quantity and bottom hole flow pressure. Through the practice of water detection and plugging technology in the Bohai Q oilfield, the pilot test well greatly reduced the inter-layer interference of the large section of the I and III oil groups in the second section of the Shahejie formation, and the oil well production increased by 14 times. It shows that the grey correlation method can effectively identify the water horizon and contribute to the implementation of profile control and water shutoff.