Reservoirs Charactrerization For The Sinian Dengying Formation Of Gaoshiti Area In Sichuan Basin

Since Weiyuan gas field was drilled successfully in Sinian Dengying Formation of Weiyuan structure in 1964, no significant breakthrough has been made in Sinian Formation of Sichuan Basin after nearly 50 years’exploration. Recently Gsl Well located in the eastern section of Leshan-Longnvsi palaeo-uplift in central Sichuan has achieved a significant breakthrough in Sinian Dengying Formation, further confirmed that the Sinian Formation of Leshan-Longnvsi palaeo-uplift has good gas-bearing properties and huge exploration potential. Aim at thesis’study object, the reservoir characteristics, reservoir formation mechanism, reservoir control factors and reservoir distribution of Sinian Dengying Formation in Gaoshiti areas of central Sichuan Basin is analysed in this paper, and the oil-gas accumulation conditions are evaluated.lt takes carbonate sedimentology and reservoir geology theory as guidance, and comprehensively utilizes information in outcrop, core observation, cast thin section, scanning electron microscopy, cathodoluminescence, and other analysis results.Sinian Dengying strata the Sichuan Gaoshiti region, deposition, diagenesis, structure, source rocks and reservoir system, made the following conclusions and understanding:Regions Aurora of Gaoshiti Dengying stratigraphic thickness was gradually thinning trend from northwest to southeast, but little change in the overall, reflecting the overall stability of the thickness of sedimentary strata. Coarse to fine-grained dolomite, sparry algal clumps in the main reservoir rock dolomite type of algae stack varve crystalline dolomite. The Sinian Dengying set of lights four favorable sedimentary facies located in tidal flat to the intertidal zone to algae cloudy. Dengying Formation sedimentary subfacies bottom-up as follows:light period of development intertidal and subtidal; the 2th member of dengying formation development tide with intertidal and subtidal; the 3 th member of dengying formation developmental subtidal zone; the 4th member of dengying formation developmental intertidal zone. According to the casting, conventional flakes, log interpretation, and the physical properties of the study area Dengying Formation reservoir characteristics Sinian system. Pointed out that the the favorable horizon Dengying Formation reservoir rock vertical development area Sinian for Dengying Formation the 2th and 4th member of dengying formation. Among them, the 2th member of dengying formation upper most developmental, times for the 4th member of dengying formation; better laterally reservoir continuity. Reservoir space to intergranular hole, intergranular dissolved pores, caverns is developed minor cracks. Dengying Formation reservoir cracks-vug; reservoir overall is a low porosity and permeability reservoirs.Tectonic evolution and hydrocarbon source rock analysis results of comprehensive analysis Tong Bay of movement Ⅰ, Ⅱ curtain uplift southeast of Leshan-Dragon Temple. Pointed out that the study area Dengying Formation karst reservoir still developmental. Tectonic evolution and reservoir master factors analysis pointed out that the main the Hechuan areas Dengying Formation tectonic-lithologic reservoirs in the multi-phase hydrocarbon migration adjustment development Dengying group structure-lithologic reservoirs with greater exploration potential.