川东北地区普光气田飞仙关组储层孔隙演化

PORE EVOLUTION OF RESERVOIRS OF FEIXIANGUAN FORMATION IN PUGUANG GASFIELD IN NORTHEASTERN SICHUAN

王恕一 蒋小琼 管宏林 鲍云杰

Wang Suyi Jiang Xiaoqiong Guan Honglin Bao Yunjie

中国石油化工股份有限公司, 石油勘探开发研究院, 无锡石油地质研究所, 江苏, 无锡, 214151

Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214151, China

川东北地区普光气田飞仙关组储层主要为台地边缘鲕滩沉积,岩性主要为鲕粒白云岩和结晶白云岩。成岩早期受大气淡水溶蚀,形成一些次生溶孔,但和原生孔隙一起多被早期胶结物填塞。白云化也产生少量晶间孔,一般小于1%,现今有效孔隙主要为埋藏期形成的溶蚀孔缝。埋藏溶蚀大致发育两期,Ⅰ期埋藏溶蚀发生在构造挤压之后,石油充注之前,溶蚀作用与富含有机酸和二氧化碳的酸性流体有关,形成的溶蚀孔隙约占现今储层孔隙的40%;Ⅱ期埋藏溶蚀发生在充注石油演化为沥青之后,溶蚀流体可能与TSR反应产生的酸性流体有关,形成的孔隙约占现今储层孔隙的60%。孔隙演化表明,对普光气田优质储层贡献最大的成岩作用是白云化作用、构造挤压作用和早、晚两期埋藏溶蚀作用。

The reservoirs of Feixiangaun Formation in Puguang gasfield in northeastern Sichuan are mainly consisted of sediments of platform marginal ooilite beach,with principle rocks of ooilite dolomite and crystalline dolomite.Due to fresh water dissolution in the early stage of diagenesis,some secondary solutional voids were developed.However,these voids and the primary pore were largely filled by early cement.Small amount,normally less than 1%,of intercrystalline pore was formed as a result of dolomitization.Present effective pores mainly are solutional voids and fractures formed during the burial period.There were two stages of burial dissolution,with stage Ⅰ was developed after structural compression but before oil filling.Dissolution was related to acid flow with rich organic acid and carbon dioxide.The pores formed in this period accounted for 40% of present porosity of reservoirs.Stage Ⅱ dissolution was developed after the filled oil was transferred to bitumen.The acid flow might be related to the pro-ducts of themochemical sulfate reduction(TSR).Its porosity accounted for 60% of present reservoirs.In terms of pore evolution,the favorable diagenesis for formation of good reservoirs included dolomitization,structural compression and early and late burial dissolution.

中国石油化工股份有限公司油田事业部项目(YTB2006-01)

https://doi.org/10.11781/sysydz200901026