Evaluation On Carbonate Reservoir Of T1j⁵¹～T2l¹¹ Formation In Huangjiachang-Longchang Area

Huang Jiachang-Longchang area is located in the edge zone of Luzhou palaeohigh,there are plenty of petroleum and natural gas resources, Changba, Maliuchang reservoir, etc. have gas in Jia Lingjiang formation. T1j51~T2l11 formation in the study area are semi-confined~restricted sea platform facies,pinhole development,reservoir heterogeneity,diagenesis complicated, the control factor and the distribution of beneficial reservoir are complicatd and these will affect the exploration outcome..According to the well testing report, T1j51 formation of Ling1 well produced 3.34×104m3/d gas in the well testing in 2008, and this demonstrated its excellent exploration potential. In this case, in order to guide further exploration and development.this paper studies firstly reservoir characteristics,the distribution of reservoir parameters and reservoir distribution, etc. and evaluates the reservoir further on this basis.Analysing the study area's various datas belonged to T1j51~T2l11 formation,such as the data of drilling.sample logging.well logging.testing and laboratory test, adopting the methods combined with the traditional fundamental geology and mathematical geology, summarizing previous research results of this area ,this paper studies and evaluates the reservoir of T1j51~T2l11 formation.According to previous research of the sedimentary facies of Shunan region,T1j51~T2l11 formation in the study atea are roughly divided into sub-limit sets flat subfacies, semi-restricted lagoon subfacies and tidal flat subfacies.Studying the petrology characteristics of reservoir rocks,diagenesis,reservoir space types,pore structure and reservoir characteristics,this paper have this conclusion:first,rock types of T1j51~T2l11 are complexed,and the most are microcrystal~calcsparite limestone and dolomite.reservoir space type is complicated,and the most are intergranular dissolution pores and intragranular dissolution pores;second,the pore throat types of T1j51 mainly is medium-narrow.and the pore throat types of T2l11 mainly is large-medium;third,the sedimentary environment and diagenesis affect the reservoir's property.Among them,the contribution of dissolution was positive ,while cementation and filling could reduce the porosity and the permeability.Permeablity is more sensitive. This paper uses logging data to distinguish reservoir.On this basis,it use the methods of support vector machine method and multiple regressionfor to calculate porosity and water saturation.Based on the physical parameters of the reservoir,pore structure parameters and the classification criteria of marine carbonate rocks in Sichuan,the reservoirs are divided into four categories,Then,the category of the single well is decided by the layers'overwhelming category. The most reservoir types of this area areⅡandⅢ, the main reservoir type of T2l11 isⅡ,and the main reservoir type of T1j51 formation isⅢ;Comprehensively analysing the distribution of reservoir and physical parameters and the classification of the reservoir,combining with the gas and water distribution, the author conducts a comprehensive evaluation of T1j51~T2l11's reservoir, and find out the more favorable zones.