塔里木盆地玉北地区奥陶系鹰山组油藏成藏特征及主控因素

油气成藏主控因素不明是目前制约玉北地区油气勘探的主要原因。玉北1断裂带成藏特征研究表明，玉北1井区奥陶系鹰山组油藏为受不整合控制的、与碳酸盐岩古岩溶有关的岩溶-缝洞型油气藏。鹰山组碳酸盐岩发育孔隙、孔洞、裂缝3类储集空间，从而形成裂缝-溶蚀孔洞型、裂缝型、孔洞型3类储层，其中裂缝-溶蚀孔洞型储层是该区最重要的储层类型。油藏范围主要受分布不均一的岩溶缝洞储集体控制，储层非均质性极强，具有大面积叠置连片和不均匀含油特点。鹰山组油藏经历多期成藏，海西晚期为主成藏期。油气成藏主控因素研究表明，玉北地区油气聚集成藏主要受油源、储层、输导体系和盖层的综合控制。油源是该区油气成藏的基础；断裂、不整合面构成的立体输导网络，为油气运移提供了优质的运移通道；储层发育程度控制了油气藏的形成及规模；巴楚组下泥岩段、中泥岩段等区域性盖层为油气保存提供了保障。在成藏特征和成藏主控因素分析的基础上建立了"断裂通源，网状输导，储层控富，海西晚期成藏，后期调整"的玉北地区奥陶系鹰山组油气成藏模式。

Characteristics and main controlling factors of hydrocarbon accumulation in Ordovician Yingshan Formation in Yubei area,Tarim Basin

Poor understanding of the main factors controlling hydrocarbon accumulation is the major constraint of petroleum exploration in Yubei area of Tarim Basin at present.The characteristics of hydrocarbon accumulation in Yubei 1 fault belt were studied.Oil reservoirs in the Ordovician Yingshan Formation in Yubei-1 wellblock are of karst-fractured vuggy type controlled by unconformity and related with paleo-karst of carbonate rocks.The reservoir spaces of the Yingshan Formation carbonates consist of pores,vugs and fractures,and the reservoirs can be divided into 3 types,namely fractured-vuggy type,fractured type and vuggy type,of which the fractured-vuggy type is the most significant in this area.The reservoir distribution is mainly controlled by the karst of carbonate rocks.The reservoirs are characterized by strong heterogeneity,vertical superimposition and lateral connection in large area,as well as uneven oil-bearing property.The Yingshan Formation reservoirs experienced multiple phases of hydrocarbon accumulation,of which the Late Hercynian was the major one.Hydrocarbon accumulation in the study area was jointly controlled by oil sources,reservoir,carrier system and cap rock.The oil sources were the foundation of hydrocarbon accumulation.The three-dimensional carrier network consisting of faults and unconformities provided high quality pathway for hydrocarbon migration.The reservoir distribution controlled the formation of the pools and their scales.Mudstone intervals in the Lower and Middle Bachu Formation provided regional seals for the preservation of oil and gas.Based on the analysis of reservoir characteristics and controlling factors of hydrocarbon accumulation,we established a hydrocarbon accumulation pattern for the Yingshan Formation reservoirs in Yubei area.