Characteristics And Distribution Of Reef Slope Reservoirs In Ordovician Lianglitag Formation In Taizhong No. 10

The Lianglitage Formation of Upper Ordovician in Tazhong area platform interior has broad deposition area, the exploration potential is also greater. The favorable lithology combination, late tectonic movement and paleo karsts reform, make the reef-bank of platform interior has good exploration prospects. The Upper Ordovician Lianglitage formation of the Tarim Basin in the10th tectonic belt is research objectives. Take Sedimentary petrology. Petroleum Geology. Carbonate Reservoir Geology. Structural Geology and other theories as the guide and use geological-geophysical technical means to describe the feature of reservoirs. Take the research of its distribution. Analysis control factors of reservoir from lithologic facies, palaeogeomorphology and structural faults. Combine with well and seismic, point out the distribution area of reservoir.In the study region Lianglitage formation, lithologic characters of the primary reservoir are grainstone, bioclast calcarenite. bioclast limestone, bondstone, micrite limestone grainstone and bioclast calcarenite proportion are70%. Reservoir spaces contain dissolved holes, dissolved pore, intragranular dissolved pore, intergranular dissolved pore,mold hole and cracks. Reservoir types are given priority to holes and crack-holes. On the whole study area reservoir has the characteristics of low porosity and low permeability that porosity concentrated distributes in the range of less than2.0%and permeability distributes between0.01-0.1mD. The reservoir evaluation of I reservoir is2.2%, II reservoir is18.2%, III reservoir is79.6%.Reservoir concentrated distribute in the first and second section of Lianglitage which is apart from the limestone top135m range and the lateral continuity is better.However, reservoir of the third and fifth section is less and distributes isolation.The development of reef reservoir is controlled by many factors. Sedimentary facies is the most important controlling factors. The most abundant reservoir is developmental in high energy reef-bank. Atmospheric freshwater dissolution created favorable condions for reservoir hole development. Weathering crust karst reform the early holes, form hign quality reservoirs. Tectonic fault increase the connectivity and permeability of reservoirs. Improve the properties of reservoirs, nearer the distance fracture, the reservoirs properties, the better.Reef-bank reservoir of Lianglitage formation seismic reflection types are classified into weak surface reflection, beaded reflection, surface strong inside layer reflection and surface strong inside continuous strong reflection. High construct topography and fracture development zone are mainly for the beaded reflection and surface strong inside layer reflection, reservoir physical property is better. However, low construct topography and fracture less development zone are mainly for the surface strong inside continuous strong reflection and surface weak reflection, reservoir physical property is weaker.Reef-bank reservoir in the study region are mainly distributed in high energy reef-bank, high karst landforms. strike-slip faults developed area, beaded reflection and surface strong inside layer development zone which is provided key point for the reservoir of the study area and further exploration. Thesis enriches the study of Tazhong area intra-platform reef reservoir development type and characteristics and provide some guidance for the next oil and gas exploration in the study area.