石油与天然气地质
石油與天然氣地質
석유여천연기지질
OIL & GAS GEOLOGY
2015年
4期
555-562
,共8页
张凤奇%武富礼%蒙晓灵%高兴军%张海%李程善%王宝萍
張鳳奇%武富禮%矇曉靈%高興軍%張海%李程善%王寶萍
장봉기%무부례%몽효령%고흥군%장해%리정선%왕보평
差异性%有效厚度%物性下限%中生界%鄂尔多斯盆地
差異性%有效厚度%物性下限%中生界%鄂爾多斯盆地
차이성%유효후도%물성하한%중생계%악이다사분지
difference%effective thickness%porosity and permeability cutoff%Mesozoic%Ordos Basin
运用铸体薄片鉴定、扫描电镜、阴极发光与压汞等测试分析,综合多方法相互印证分析了鄂尔多斯盆地S地区中生界主力含油层系有效厚度物性下限,并结合物性变化的定量表征探讨了各主力油层间有效厚度物性下限的差异性成因。结果表明,研究区储层有效厚度物性下限值随埋深增大而变小,延9油层组、长2油层组和长6油层组(长4+5油层组)的孔隙度下限分别为15%,14%和8%,渗透率下限分别为4.0×10-3,1.0×10-3和0.15×10-3μm2。沉积作用形成各储层矿物成分中刚性颗粒含量与粒度大小等差异是其物性差异性形成的基础影响因素,而成岩作用是其差异性形成的最主要原因。各成岩作用类型的具体影响为:各储层初始孔隙度相差较小,长2油层组与延9油层组相比,压实作用和胶结作用共同作用而减少的孔隙度基本相当,差别在于后者的溶蚀改善作用增加的孔隙度稍好于前者;长6油层组(长4+5油层组)与长2油层组相比,压实作用减少的孔隙度和溶蚀作用增加的孔隙度差别均不大,差别在于前者因胶结作用减少的孔隙度大于后者,这是两者物性下限差异的最主要原因。
運用鑄體薄片鑒定、掃描電鏡、陰極髮光與壓汞等測試分析,綜閤多方法相互印證分析瞭鄂爾多斯盆地S地區中生界主力含油層繫有效厚度物性下限,併結閤物性變化的定量錶徵探討瞭各主力油層間有效厚度物性下限的差異性成因。結果錶明,研究區儲層有效厚度物性下限值隨埋深增大而變小,延9油層組、長2油層組和長6油層組(長4+5油層組)的孔隙度下限分彆為15%,14%和8%,滲透率下限分彆為4.0×10-3,1.0×10-3和0.15×10-3μm2。沉積作用形成各儲層礦物成分中剛性顆粒含量與粒度大小等差異是其物性差異性形成的基礎影響因素,而成巖作用是其差異性形成的最主要原因。各成巖作用類型的具體影響為:各儲層初始孔隙度相差較小,長2油層組與延9油層組相比,壓實作用和膠結作用共同作用而減少的孔隙度基本相噹,差彆在于後者的溶蝕改善作用增加的孔隙度稍好于前者;長6油層組(長4+5油層組)與長2油層組相比,壓實作用減少的孔隙度和溶蝕作用增加的孔隙度差彆均不大,差彆在于前者因膠結作用減少的孔隙度大于後者,這是兩者物性下限差異的最主要原因。
운용주체박편감정、소묘전경、음겁발광여압홍등측시분석,종합다방법상호인증분석료악이다사분지S지구중생계주력함유층계유효후도물성하한,병결합물성변화적정량표정탐토료각주력유층간유효후도물성하한적차이성성인。결과표명,연구구저층유효후도물성하한치수매심증대이변소,연9유층조、장2유층조화장6유층조(장4+5유층조)적공극도하한분별위15%,14%화8%,삼투솔하한분별위4.0×10-3,1.0×10-3화0.15×10-3μm2。침적작용형성각저층광물성분중강성과립함량여립도대소등차이시기물성차이성형성적기출영향인소,이성암작용시기차이성형성적최주요원인。각성암작용류형적구체영향위:각저층초시공극도상차교소,장2유층조여연9유층조상비,압실작용화효결작용공동작용이감소적공극도기본상당,차별재우후자적용식개선작용증가적공극도초호우전자;장6유층조(장4+5유층조)여장2유층조상비,압실작용감소적공극도화용식작용증가적공극도차별균불대,차별재우전자인효결작용감소적공극도대우후자,저시량자물성하한차이적최주요원인。
Analytic means including thin section examination, SEM, cathode luminescence, mercury penetration and so on,were applied to determine the cutoffs of porosity and permeability for calculating the effective thickness of the major Mesozoic oil-bearing formations in S region of Ordos Basin.The reasons for the varying cutoffs were also discussed based on quantitative characterization of physical property changes of the formations.The results show that the cutoffs( porosity and permeability) decline with the increase of burial depth.Samples from Yan 9,Chang 2,Chang 4+5 and Chang 6 for-mations,have porosity cutoffs of 15%,14%,8%respectively,and permeability cutoffs of 4 ×10-3 ,1 ×10-3 ,0.15 ×10-3μm2 respectively.The differences in content and grain size of rigid particles in mineral composition of each reservoir caused mainly by sedimentation processes are regarded as the basic factor for the difference of cutoffs,while diagenesis is the major factor.The processes,including compaction,cementation and corrosion,dented the formations in different ways.All the formations had the similar porosity at first.But later on it turned out that Yan 9 had a higher porosity than that of Chang 2 because of their different response to corrosion and Chang 4+5 had lower porosity than that of Chang 2 because of their different behavior under cementation.