A Study On Experiments For Carbonate Rocks Dissolution In Burial Environment And Its Significance In The Reservoir

Carbonate rocks are widely distributed in the world,the oil and gas yield of carbonate reservoir is huge,so intensive study of the Carbonate rocks is necessary.It is well known that storage space of carbonate reservoirs are secondary pores mainly,the proportion of dissolved pores is significant.Therefore,the study of the formation mechanism of dissolution porosity provides a theoretical basis for the exploration of carbonate reservoirs.Domestic and foreign scholars have carried out a series of experiments on the dissolution of carbonate rocks,the controlling factors of carbonate dissolution porosity are explored.On the basis of previous research results,carrying out experiments of carbonate dissolution in deep burial stage by using self-designed experimental instrument,to explore the main factors influencing the formation of carbonate rock dissolution porosity.By calculating the dissolution of the experimental samples of carbonate rocks under different experimental conditions,the following experimental results are obtained:(1)Under the same experimental conditions,calcite is always easier to be dissolved than dolomite;(2)Gypsum and salt rock solution promote the dissolution of dolomite,restrain the dissolution of calcite;(3)Acidic solution has obvious effect on carbonate rock dissolution,it can dissolve carbonate rock to produce more secondary dissolution pores;(4)Under the condition of flow experiment promotes dissolution of carbonate rocks.Based on the characteristics of core,thin-section,physical properties and fluid inclusions,it is found that the highly development of secondary porosity of the Lower Paleozoic dolomite reservoirs in eastern Tarim Basin and deep-buried carbonate reservoirs of the giant Puguang gas field in Sichuan Basin.Acid fluid dissolve the deep dolomite lead to the development of secondary porosity.