Refined reservoir evaluation of the second member of Shanxi Formation in mid-eastern Ordos Basin
Online published: 2010-09-15
Shanxi Formation in mid-eastern Ordos Basin can be divided into three sedimentary sequences.SQ8 (the second member of Shanxi Formation)can be divided into lowstand system tract,transgression system tract and highstand system tract,with the main sand body developed in lowstand system tract.SQ8一LST can be subdivided into three progradational parasequence sets,which prograded into the lake.They are L1,L2 and L3 from below to top with the thickness varying from thin to thick and the distribution area from small to large.In L1 parasequence set,only one main sandstone belt deposited in the study area,which extends nearly north-southward with the length of 100 km,10~15 km in wide,and with the sandstone thickness of 2~ 10 m.In L2 and L3 parasequence sets。the sandst0ne distribution are very similar,developed 5~6 north-southward and north-eastward sandstone belts,which are 10~25 km in wide,200~230 km in length,with the sandstone thickness of 4~20 m.L1 parasequence set is initial filling deposition after large scale marine regression.Its sandstone composition is complicated with poor sorting and the reservoir property is relatively poor.But up to the parasequence sets of I22 and L3,the reservoir properties becon1e better obviously.Favorable reservoir sandstones developed in sedimentary facies of distributary channel in delta plain,subaqueous distributary channel and mouth bar in deha front,which mainly distributed in middle-upper part of the lowstand system tract.The reservoir property of delta front sand body is better than that of delta plain sand body,while point bar sand body is poorer in reservoir property.
Key words: pore shape; equivalent modulus; fluid substitution; forward modeling; AVO response
HU XiaoLi , TAN Dalong . Refined reservoir evaluation of the second member of Shanxi Formation in mid-eastern Ordos Basin[J]. Lithologic Reservoirs, 2010 , 22(3) : 71 -77 . DOI: 10.3969/j.issn.1673-8926.2010.03.014
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