延安地区长6储层非均性特征

(1.陕西省地质调查院,陕西 西安 710054; 2.长安大学 地球科学与资源学院,陕西 西安 710054; 3.陕西省煤田地质局 一三一队,陕西 渭南 715400)

储层非均质性; 沉积相; 长6油层组; 延安地区

Reserivoir heterogeneity characteristics of Chang 6 reservoir in Yan'an Area
LIU Xiao-feng1,LIANG Ji-wei2,GUO Xiao-dan3,XUE Xu-ping1

(1.Shaanxi Province Institute of Geological Survey,Xi'an 710054,China; 2.College of Earth Science and Resources,Chang'an University,Xi'an 710054,China; 3.Team 131,Shaanxi Provincial Coalfield Geology Bureau,Weinan 715400,China)

reservoir heterogeneity; sedimentary facies; Chang 6 reservoir; Yan'an Area

DOI: 10.13800/j.cnki.xakjdxxb.2019.0317

备注

储层的物性是影响油气的聚集、储存和开采的重要地质因素。通过岩芯薄片、测井曲线、钻井资料等数据的统计分析,对延安地区延长组长6油层储集层的层内、层间和平面的非均质性特征进行研究,进而确定储层非均质性对油藏的形成及开发的影响。结果 表明:延安地区长6储层为三角洲前缘亚相,水下分流河道砂体为主要的储油层,河道主体相对河道两侧非均质性较弱,储层表现为低孔-低渗的特征,层内非均质性较强,以下细上粗的反韵律为主,层理较发育,泥质夹层和钙质夹层为主要的层内夹层,渗透率表现为低孔-低渗的特征; 储层内部单砂层较多且不连续,分层系数较大,层间隔层较发育,层间非均质性较强; 从平面非均质性来看,砂体以条状、片状为主,砂体整体连通性一般较好,水下分流河道砂体的非均质性较弱,分流间湾、河口坝和天然堤等砂体的非均质性较强。从单层砂体来看,长62分层系数最大,层间隔层最多,层间非均质性最强; 长64整体砂厚较薄,有效砂岩密度最小,非均质性也较强。

Reservoir heterogeneity is an important geological factor that affects the accumulation,storage and exploitation of oil and gas.Based on the statistical analysis of data such as core sheet,logging curve and drilling data,the heterogeneity characteristics of interlayer,in-layers and planar in Chang 6 reservoir of Yanchang Formation in Yan'an Area are analysed and studied in order to confirm the impact of reservoirs on the formation and development of reservoirs.The results show that the Chang 6 reservoir of the Yan'an Area is the delta front subfacies,and the underwater distributary channel sand body is the main reservoir.The main body of the river is relatively weak in heterogeneity on both sides of the channel,and the reservoir is characterized by low porosity.The reservoir has the characteristics of low permeability,strong heterogeneity,anti-rhythm of fine in the upper and rough in the lower layer,more developed bedding,the argillaceous interlayer and the calcareous interlayer as the main interlayer,and low permeability.Single sand layer inside the reservoir is more and discontinuous,and the layering coefficient is larger.The interlayer layer is more developed,and the interlayer heterogeneity is stronger; from the plane heterogeneity,the sand body is mainly in strips and sheets,the overall connectivity of sand bodies is generally good,and the heterogeneity of underwater distributary channel sand bodies is weak.The heterogeneity of sand bodies such as diversion bays,estuaries and natural dikes is better and stronger.From the perspective of single-layer sand body,the long 62 layering coefficient is the largest,the layer spacing layer is the most,and the interlayer heterogeneity is the strongest; the length 64 overall sand thickness is thinner,the effective sandstone density is the smallest,and the heterogeneity is also strong.