渤海蓬莱9-1中生代花岗岩储层特征及有利区带分析

Reservior Characteristics of Mesozoic Granite in Penglai 9-1 and Prediction of Potential Development Area

渤海湾盆地蓬莱9-1油田潜山勘探获得重大突破,在花岗岩中见到较好油气显示,单井试油获得工业油气流。然而,对该套花岗岩的形成时代、产状、分布规模、岩性特征、储集空间类型、储层主控因素等并不十分清楚。本文通过对潜山钻井取心、井壁取心、岩屑的系统观察、描述以及选取样品进行单颗粒锆石U-Pb同位素定年、岩相学鉴定等测试,确定该花岗岩为中生代时期的侵入到元古宇地层中的酸性侵入体。进一步采取铸体薄片鉴定、物性分析等测试手段确定储集空间类型为破碎粒间孔、溶孔、风化收缩缝、构造裂缝等,主要以潜山风化壳油气藏为主,风化花岗岩中下部孔隙和裂缝发育较差,横向非均质性强,为岩性油气藏模式。结合测井和地震等手段,对侵入体侵入方向、侵入规模等进行了研究,为花岗岩体储量申报奠定了扎实的基础,同时,对类似蓬莱9-1花岗岩体以及结晶基岩有利储层分布研究,具有重要的借鉴意义。

We made major breakthroughs in exploration in buried hills of Penglai 9-1 oilfield in Bohai basin. There is good oil-gas show in granite, which already forms oil-gas pools. However, there are some uncertainties in this set of granites, such as forming time, attitude, distributing scope, lithology characteristic, reservoir space types, major controlling factor of reservoir and so on. Systematic observation, description of drilling cores, sidewall cores and cuttings, zircon U-Pb dating, petrography and geochemistry studies show that the granite is a Mesozoic acid intrusion in Proterozoic strata. The analyses such as casting thinsection observation and physical property analysis show that the reservoir space types in the granite are broken intergranular pores, dissolution pores, weathering fractures, structural fractures, etc. and it is mainly a pool of weathering crust which is strongly transverse homogeneous lithologic petroleum reservoir whose lower cores and fractures develop badly. Combined with logging and seismic method, we also studied the intrusive direction and scale of the granite, which built solid foundation for declaring the reserves of oil and gas in the granite and had instructive meanings for the study of reservoir distributing in the similar Penglai 9-1 granites and crystal basement rock.