The Study Of Characteristics Of Ma5₁₊₂ Reservoir In Huanglong Block

To provide the geological basis for the effective development of gas in Ma51+2 reservoir in Huanglong block, this paper, closely linked to the actual situation of exploration and development, further research the distribution of the karst palaeogeomorphology before carboniferous period and reservoir characteristics by means of comprehensive utilization of well log information、well drilling information、well log information、test data、data of gas test and production. Through the division and correlation of intended interval, set up the regional stratigraphic framework,and summarize the characteristics of stratigraphic development; Implemente ancient tectonic evolution characteristics and current tectonic characteristics of intended interval in the region of interest; Analyze the sedimentary environment in Ma51+2 period,and summarize the type and distribution characteristics of sedimentary micro facies; According to the actual situation of the region of interest,choose the applicable ways to recover the karst palaeogeomorphology, establish the partition criterion for the karst palaeogeomorphology before carboniferous period in the region of interest,and recover the karst palaeogeomorphology; Make the detailed discussion on petrology characteristics、preserving spaces、pore structure、physical property characteristics、diagenesis and aeolotropism of reservoir, summarize the main factors of affectting the physical property of reservoir;finish the research in the comprehensive evaluation of reservoir.The research shows that,during the period of Ma51+2, the sedimentary environment was the tidal flat of continental sea and there were anhydrite-bearing dolomite platform、 anhydrite-dolomite platform、dolomite platform and so on in the region of interest; the karst palaeogeomorphology before carboniferous period can be divided into the two-level palaeogeomorphology units of karst platform and karst slope,and can be further divided into eleven sort three-level palaeogeomorphology units,such as depression、dissolution delve、 dissolution hammock and inherited uplift; in the region of interest,the average porosity of Ma51+2 reservoir is 1.63% and the average permeability is 0.198×10-3μm2,so the Ma51+2 reservoir belongs to the low、extralow porosity and extralow permeability reservoir; the physical property of reservoir is mainly dominated by sedimentary micro facies、micro pore structure、diagenesis and karst palaeogeomorphology; after the comprehensive consideration of various factors, the reservoir can be divided into three types (class Ⅰ, Ⅱ, Ⅲ).