Research On Characteristics And Distribution Of Effective Sand Body In Shan1and He8Section Of Suligearea

Sulige gas field is not only the biggest gas field finding in China, but also the gas field withthe greatest difficultly exploitation at present. This gas field has the characteristics of a very rarelow permeability, low abundance, and high heterogeneity. This article on the base of making fulluse of the experience from Sulige low permeability sandstone gas reservoir’s preliminaryevaluation, deeply analyses the lithological combination and the log response features of differentgenetic type sandstone.Associating with other scholars’ research of Sulige, the author think that S6is fluvial facies’sedimentation, and according to the hydrodynamic strength and the sedimentary sandstone body’sfeatures, divides S6into nine sedimentary microfacies types, which are high-energy river char,high-energy river point bar, low-energy river point bar, low-energy river char, abandoned channel,bet lands, crevasse splay, natural levee, channel lag deposit microfacies types. S6is fluvial faciessedimentation: the upper of He8and Shan are meandering river sedimentation; the lower of He8is braid river sedimentation. The high-energy river char (point bar) is the most favorable reservoir,and other microfacies with better physical property also can develop effective sandstone.Thisarticle also carries out the research of sedimentary sandstone bodies’ spatial distribution. As aresult of rivers’ convergence effect, the development advantage of the sandstone near provenancearea isn’t apparent, and the sandstone also has thicker development in central and southern of thestudy area.This article takes containing a gas bearing formation sand body as effective sandstone, butSulige belongs to low porosity and low permeability and nearly tight reservoir, so conventionalwell logging identification methods have certain defect in gas reservoir identification. This studyimproves the conventional well logging identification methods to more suitable for the tight gas reservoir identification and achieves good results. Through the improvement of conventional welllogging identification methods, three-porosity overlay method, three-porosity difference valuemethod, time difference of sonic transit method and fluid acoustic ratio method have betterapplication effect in tight gas bearing formation’s identification.This article takes further study of the effective sand bodies’ distributed rule and controlfactors. According to the above research, we get those results and understanding.Because S6isfluvial facies’ sedimentation, the river frequently changes its route, and sandstone multiphasesuperimposition, so when the char (point bar) deposited there are must have bet lands andabandoned channel sedimentation of mudstone and aphanitic-siltstone mixed in it. This makeseffective sandstone distribution isolated. Some diagonal effective sandstones are the mostfavorable sedimentary sandstones.