铁山气田龙会场区块飞仙关组鲕滩储层特征及主控因素

Characteristics and main controlling factors of oolitic beach reservoirs in Feixianguan Formation,Longhuichang block,Tieshan gasfield

1987年至今,铁山气田龙会场区块下三叠统飞仙关组气藏获多口工业气井,但区块面临单井储层物性、产量差异大、储层纵横向展布以及主控因素不清楚等问题而导致的勘探开发困境。为此,基于钻井、岩心描述、压汞实验分析以及测井研究成果等资料分析储层特征,利用三维地震刻画鲕滩储层纵横向展布规律,进一步研究储层发育主控因素,落实剩余储量分布,为气藏后期生产提出制度调整、措施优化建议、提高采收率、实现效益开发提供支撑。研究表明:(1)飞仙关组岩性以溶孔残余鲕粒白云岩、结晶白云岩为主,表现为低孔、低渗特征。(2)储层以Ⅲ类为主,早期鲕滩储层具有波峰或杂乱反射的地震响应特征。(3)储层鲕粒滩发育,龙会场西(华(2)号断层以西)与龙会场主体发育特征有差异。龙会场西比龙会场主体厚度薄,纵向上主要发育在飞二层序。(4)沉积环境是储层发育的基础,白云石化及溶蚀作用在储层形成过程中起关键性作用,后期构造作用也对改善储层的储渗性能起着辅助作用。

Since 1987,several industrial gas wells have been drilled in gas reservoirs of the Lower Triassic Feixianguan Formation of Longhuichang block,Tieshan gasfield.The block is faced with difficulties in exploration and development caused by the problems of big differences in reservoir physical properties and production of single well,unclear longitudinal-transverse distribution and main controlling factors of reservoir.Therefore,the reservoir characteristics were analyzed based on drilling data,core description,mercury injection experiment,and logging data.The law of longitudinal-transverse distribution of oolitic beach reservoirs was depicted by using 3D seismic.Furthermore,the main factors controlling reservoir development were studied,and the distribution of remaining reserves was confirmed.These provide support for offering suggestions of system adjustment and measure optimization for the later production,enhancing gas recovery,and realizing benefit development.Research shows that:(1)this Formation is dominated by dissolved pore residual oolitic dolomites and crystalline dolomites,characterized by low porosity and low permeability;(2)the reservoirs are mainly type III,and oolitic beach reservoirs in the early stage are featured by wave crest or chaotic reflection in seismic response;(3)oolitic beach is developed in the reservoirs,and there are differences in the development characteristics between the western Longhuichang(west of Hua 2 fault)and main body of Longhuichang;the western part is thinner than the main body,it mainly develops in the second member of Feixianguan Formation vertically;and(4)sedimentary environment is the foundation of reservoir development,dolomitization and dissolution play a key role in forming reservoir,and later tectonization is also conducive to improving reservoir property and permeability.