| Yudong1 condensate gas reservoir is located at Yudong-Yingmaili area in the western tip of the northern uplift of the Tarim Basin,discovered in October 2008.After the evaluation of exploration in recent years,gas reservoir geological understanding deepening gradually,At present,it is basically proved that is a super deep,ultra-thin,ultra-low abundance,medium porosity,medium permeability condensate gas reservoir.The preliminary estimation of the geological reserves of condensate gas is about 28.6 billion cubic metres.According to the preliminary exploration and gas reservoir evaluation results,through detailed study of sedimentary reservoir and reservoir characteristics in two aspects,then in accordance with relevant standards for the development of conceptual design,to provide technical support for the Yudong1 condensate gas reservoir development to achieve high quality and high benefit.The following are the main understandings:(1)Yudong1 condensate gas reservoir is a little affected by the tectonic activities,in a North dipping slope area,a"North South high-low"by the distribution of sandbody updip control Paleogene lithologic reservoir of thin sand.It has the characteristics of"large and thin".The gas bearing area is large(about 219 km~2),and the reservoir is super deep and ultra-thin.The burial depth is about 5000m,the thickness is very thin,the reservoir is about3-5m,and the production layer is only about 3m.(2)The main target reservoir cap assemblage of this gas reservoir is Paleogene lower gypsum and mudstone section and bottom sandstone section.According to the sedimentary cycle,it can be divided into four sand groups,of which the Paleogene 3rd sand group is the production section of the gas reservoir,and is a fan delta front frond leaf body.The rock type of the 3 sand group in the Paleogene is mainly feldspar lithic sandstone,which is mainly fine sandstone,and the fine sandstone is second.The main pore type is the residual primary intergranular pore,and the pore throat is dominated by middle larynx and fine larynx.The comprehensive evaluation of the production layer is a medium pore and medium permeability reservoir.(3)In the Paleogene 3rd sand group,the thickness of the sandstone interlayer is thin,which is fragmentary in a single well,and there is no stable interlayer between the interbeds.The distribution of sand bodies is flat and the reservoir is relatively homogeneous.The pressure measurement confirms that the gas reservoir has good internal connectivity and large connectivity.The production of condensate gas reservoirs are characterized as"characteristics of lightweight,low viscosity,low sulfur,low colloid and asphaltene,high wax content,"wells completion test data show that the gas reservoir is a sand-body control at normal temperature and pressure,edge water,thin layer lithology condensate gas reservoir.(4)Development plan in accordance with the overall planning,step-by-step implementation,to ensure stable production for more than 10 years,using a set of wells,the development way of horizontal well design failure,total 11 wells,well spacing 2km,gas production rate of 2.93%,with an annual output of 825 million,the scale of gas condensate68 thousand and 800 tons,the average single wells Nissan,Nissan 250 thousand gas condensate 21 tons,stable for a period of 12 years. |
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