摘要
以北部湾盆地涠西南凹陷W区流沙港组为例,结合沉积微相研究和砂体对比,利用密井网资料分析建立了正常三角洲和辫状河三角洲沉积储层定量地质知识库。根据岩性、沉积构造、特殊矿物和测井相等特征,分析认为W区流沙港组L1和L3分为正常三角洲和辫状河三角洲前缘沉积,并细分为水下分流河道、河口坝、远砂坝、席状砂和分流河道间等5种微相类型。总结出正常三角洲和辫状河三角洲微相砂体在空间上各发育了8种成因叠置模式和3种砂体接触模式。建立的定量地质知识库显示,正常三角洲水下分流河道宽厚比为1∶80~1∶100,河口坝宽厚比为1∶70~1∶90,远砂坝宽厚比为1∶80~1∶110;辫状河三角洲河口坝宽厚比为1∶60~1∶76,水下分流河道宽厚比为1∶50~1∶65。依据地质知识库成果,在W区WB油田主力层L3-ⅢB油组的调整井部署方案中将注采井距定在400~500m,实施后三口调整井开发效果均超预期,累增油6.3×104t。这一成功应用表明地质知识库的砂体组合叠置模式和发育规模定量数据为井网井距的设计提供了依据,对油田高效开发具有重要意义。
Liushagang Formation of Area W in Weixinan Sag of Beibuwan Basin is studied as a case.Quantitative geological knowledge database of sedimentary reservoirs in the normal delta and braided river delta is established by data analysis on dense well pattern combined with sedimentary microfacies research and sand body correlation.According to the characteristics of the lithology,sedimentary structure,special minerals and well logging facies,the analysis shows that the normal delta and braided river delta front are deposited in L1 and L3 of Liushagang Formation in Area W,and may be subdivided into five sedimentary microfacies including underwater distributary channel,estuary bar,distal bar,sheet sand and interdistributary channel.There are eight genetic superposition modes and three sand contact modes in space for the normal delta and braided river delta.The built quantitative geological database show that the ratio of width and thickness for the underwater distributary channel,estuary bar and distal bar of the normal delta is 1∶80-1∶100,1∶70-1∶90,1∶80-1∶110 respectively,and that of the estuary bar and underwater distributary channel of the braided rive delta is 1∶60-1∶76 and 1∶50-1∶65 respectively.On the basis of the results of the geological knowledge database,injection-production well spacing is designed as 400-500 m among the arrangement plan for the adjustment wells in L3-ⅢB reservoir of Oilfield WB in Area W.After implementation,the development results of three adjustment wells are better than the expected.Cumulative oil increased by 6.3×104 t.This successful application shows that different sedimentary microfacies assemblage patterns and quantitative scale data in the geological knowledge database provide scientific basis for the design of well pattern and well spacing.It is of great significance for efficient oilfield development.
作者
曾晓华
袁凌荣
张晓禹
李伟
朱金起
Zeng Xiaohua;Yuan Lingrong;Zhang Xiaoyu;Li Wei;Zhu Jinqi(Zhanjiang Branch of CNOOC Ltd.,Zhanjiang Guangdong 524057)
出处
《中外能源》
CAS
2021年第3期27-37,共11页
Sino-Global Energy
关键词
地质知识库
正常三角洲
辫状河三角洲
密井网
流沙港组
geological knowledge database
normal delta
braided river delta
dense well pattern
Liushagang Formation
