川中～川南过渡带河包场地区须家河组二段、四段有效储层研究

【作者】 高鹏鹏；

【导师】 蒋裕强；

【作者基本信息】 西南石油大学 ， 矿物学、岩石学、矿床学， 2007， 硕士

【摘要】 川中～川南过渡带河包场地区须家组二段、四段低孔、低渗～特低渗储层发育相对优质的有效储层,大部分油气都储集在这些“甜点”储层中。本文应用地层学、沉积学及储层地质学等理论,以岩心分析、测井资料处理解释为基础,通过对有效储层物性条件的分析及储层的精细对比,开展了有效储层下限研究及有效储层纵横向分布研究。为河包场地区须家河组下一步勘探与开发部署指出了有利的勘探开发区块和层段。结合前人研究,在地层对比的基础上,认同四川盆地须家河组按岩性六分方案,并对研究地区须家河组地层进行了再细分,按岩性、电性特征将须二段、须四段各划分为2个亚段,须六段划分为3个亚段;认为研究区的砂体成因为河流携带的物质入湖后经波浪和湖流再改造再分布形成的滩坝砂体:储层物性具低孔、低渗～特低渗的特点,储集空间以残余粒间孔和饮生溶孔为主,孔隙结构属于小孔细喉型;该类储层具有较强的应力敏感和水锁效应。针对该类储层的具体特点,利用最小流动孔喉半径法、压汞分析参数相关法、启动压力梯度法、束缚水膜测定法（气态渗吸法、核磁共振实验法）、测井解释含水饱和度～孔隙度交绘法、含水饱和度与相对渗透率组合法、地层条件下的进汞饱和度法,初步确定了储层的孔隙度下限（须二段为8%、须四段为6%）及渗透率下限0.2×10^-31μm²。利用气～水相对渗透率实验分析得到须二段束缚水饱和度为36.5%、须四段束缚水饱和度为40.5%,储层产气饱和度下限为30%,产纯气下限为60%。研究区为含水饱和度较高的低渗气藏,含水状态下,通过应力敏感研究,储层的渗透率下限可定为0.3×10^-3μm²。通过产能模拟,在不含水状态下,对须二段储层,当生产压差为5MPa、产层累计厚度为10～15米时,孔隙度大于9.6%、渗透率大于0.1×10^-3μm²就能达到工业产气标准;对须四段储层,当生产压差为5MPa、产层累计厚度为10～15米时,孔隙度大于4%、渗透率大于0.02×10^-3μm²就能达到工业产气标准。需指出,产能模拟是一个理想状态下进行的,在一定的生产压差条件下,有效储层物性下限受储层非均质性及有效厚度的影响在一定范围内可变化。根据上述储层物性及储层有效条件的研究成果,综合考虑将储层分为四类,研究区须二段以Ⅰ-Ⅱ类好～中等储层为主;须四段以Ⅲ-Ⅱ类差～中等储层为主。纵向上,主要分布在须二²亚段、须四¹亚段及须四²亚段下部,须二¹亚段不发育,但是个别井偶见发育。横向上,呈团块状、连续性差,导致研究区气水分布复杂。这些团块状分布的“甜点”区域,应是下一步勘探开发的重点。更多还原

【Abstract】 The reservoir with high quality could grow in the“the sweet dessert zone”cluster-block alike among the one with low porosity and permeability in horizontal plane in the Xujiahe formation,upper triassic system of Hebaochang area,central Sichuan-South Sichuan transitional belt.Under the guidance of new principles and methods of stratigraphic geology, sedimentology,reservoir geology,based on core anlysis and logging interpreation,through the analysis of propertity and fine comparison of effective reservior,the lower limit of effective reservior was studied and advantageous exploration development sub-area and section was indentified and selected.Based on predecessor’ previous research results,formation comparison between external and internal stratum in the targer area and the sequnce in the Xujiahe formation of Sichuan basin were seperrated in to six members according to lithology and logging and then it was taken into detailed final sorting.After repeatedly rebuilded and reallocated by wave and lake -rive,the fragmentary material that had been carried to lake through alluvial fans and rivers,formed beach -dam face sandstone along seacoast and alongshore,swamp containing coal developed shallow-shore sub-enviroment.The reservoir space are mainly remainder intergranular and secondary dissolved pore and the type of reservoir space is small pore and thin throat,which is so sensitive to compacting stress and water blocking.By means of method for testing least pore throat radius、correlation method by mercury penetration analysis、activate pressure gradient allocation metod、binding water film mensuration、water saturation and porosity correlation and water saturation phase、permeability combined method and mercury saturation under sequece compacting,porosity lower limit of reservior was determined（T₃X₄6%,T₃X₂8%）which was applied to assort and appraise reservoir. lower limit of least throat radius using gas imbibition binding water film mensuration is gained（averaged 0.0245μm of T₃X₄,averaged 0.0233μm of T₃X₂）which has very good uniformity with the result(0.0278μm by nuclear magnetic resonance experiment,binding with the relationship of permeability and mean radius,the permeabilty of T₃X₄ and T₃X₂ was 0.15×10^-3μm²and 0.18×10^-3μm²respectively and the porosity of T₃X₄and T₃X₂was 5.62% and 8.13%respectively;the bound water saturation of T₃X₄ and T₃X₂ was 40.5%with experimental analysis of gas-waterreiative permeability and 36.5%respectively;lower limit of gas saturation is 30%and one of gas saturation which can have industrial producing is 60%.With study on stress sensitivity,the damage of permeability is lower than 50%in the process of crocking up development which is to say stress sensitivity weak or medium.The permeability damage relation of dry sample and wet sample showed that when the permeability is lower than 0.3×10^-3μm²,correspondingly loss ratio of stress sensitivity was descending gently,so the lower limit of permeability of reservior with much water contained was identified as 0.3×10^-3μm².Through the capacity simulating,under the differential producting pressure condition industrial volume of producing reserves could be achieved.Under the producing presurre is 5MPa and accumulative thickness is changing from 10m to 15m,it will be effective and avilable for 2^ndmember when the porosity is above 9.6%and the permeability above 0.1×10^-3μm²;also effective and avilable for 4^thmember when the porosity is above 4%and the permeability above 0.02×10^-3μm².Last is not least,the lower limit of effective reservior is restricted and defined by the elements of heterogeneity and available thickness altogether.According to the parameter of property and pore structure and analysing results on the effctive reservior,the reservoir were classified into 4 types under the comprehensive consideration.And theⅠ-Ⅱsecondary reservior developed in the 2^ndmember（T₃X₂）and theⅢ-Ⅱsecondary reservior developed in the 4^thmember（T₃X₄）where the advantageous bed well growed in the 4th sub member(T₃X_4¹)comparatively where the advantageous bed well grow in the 2^ndsub member(T₃X_2²)which is to say the advantageous reservior developed in the middle bottom of the 4^thmember(T₃X_4¹)and upper part of the 2^ndmember（T₃X₂）.In a word,the degree of reservior development are different among the secondary structures and well segments in vertical section and it presents sandbody cluster- block alike in horizontal plane,which led to gas-water distribution so complex.And so,the further exploration and development should attach importance to "the sweet dessert zone "cluster- block alike in horizontal plane.更多还原