Keywords: 
• Tongnanba area

Abstract: T1f3 reservoir in Tongnanba area obtain industrial gasflow in recent years, reservoir pressure are high, reservoir lithology mainly is grainstone and mud microcrystalline limestone, physical properties is bad. Reservoir space mainly are oolimolds, dissolve inside grainmold hole and dissolve pore.There are big changes in transverse, and significant different in longitudinal. Generally, reservoir development poor in tongnanba area. In this article, the author deeply discussed the reservoir forming mechanism of T1f3 reservoir in tongnanba area through the analysis of the diagenesis types and it`s influence to the porosity evolution, diagenetic evolution sequence, and contrast to which in Puguang gas field. Accoroding to the research there are three factors which controll the forming of T1f3 reservoir. Firstly: Dolomitization is very weak because of the limitation of the sedimentary and diagenetic environment, so the dolomite reservoir do not develop, which lead to the poor reservoir develop; Secondly:Primary pore disappeared basicly, dissolution become the key factor to the forming of T1f3 reservoir, synsedimentary dissolution are dominant among dissolution in all stages; Thirdly:There are not TSR reaction in T1f3reservoir because of the hydrocarbon injection did not happen during the middledeep burial stage. So the destructive diagenesis enhancement relatively can not influence resevroir quality.