西湖凹陷H油气田深层气藏地质特征与开发潜力

Geological features and development potential of the deep gas reservoirs in Pinghu Formation, H field,Xihu sag

针对西湖凹陷H油气田目前亟待解决如何稳产、寻求新的产能接替等问题,对该油气田平湖组深层气藏的沉积特征以及储层岩性、孔隙结构、物性等特征进行了综合分析,认为平湖组深层为潮坪沉积体系,发育潮道、滩坝、砂坪、混合坪等砂体,横向连片叠加分布,展布范围较广,具有较好的开发潜力,其中以H3、H4、H5井区以及BJT区块PH大断裂西部P11砂层为最有利的潜力区。通过与东海地区其他低渗层的压裂产能类比及数值模拟分析,认为H油气田H4、H5井区P11气层采取水平井压裂措施后产能至少可达日产15万m3以上,而H3井P11气层更是深层气藏的甜点所在,所以该油气田深层气藏P11砂层组具有较好的开发潜力。

For the urgent problems how to keep stable production and how to find new productivity re- placement in H field, Xihu sag, the sedimentolo- gy, lithology, pore structure, and petrophysics were comprehensively analyzed for the deep gas reservoirs in Pinghu Formation. The results show that the deep intervals of Pinghu Formation are a sedimentary system of tide flat, where various sand- bodies developed, including tidal channel, beach bar, sandy flat and mixed flat. These sandbodies are lat- erally contiguous and overlapping each other, and quite widespread, and exhibit a great gas develop- ment potential, with P11 sand reservoirs in the Well H3, H4 and H5 areas and in the western PH major fracture, BJT block, most favorable to gas develop- ment. Through a comparison with the fractured pro- ductivity of other low permeability reservoirs in the East China Sea and an analysis of numerical simula- tion, it is considered that Pll sand reservoirs in the Well H3 and H4 areas, H field, may be at least up to 150 000 m3 per day of gas productivity after frac- turing stimulation with a horizontal well, and that P11 sand reservoir in H3 well is at a sweetspot. Therefore, these deep P11 sand reservoirs are better in development potential in H field.