The Gas Reservoir Description Of He 8 Member In Sulige Gas Field Su 54 Block

Due to the more and more serious environment problem in China,the natural gas as a clean energy has been used in more and more fields. China has become the largest importer of the natural gas. Gas external dependency rapid increase to 32.2% in 2014, energy security situation is grimly. Tight sandstone gas resources in China has great potential, especially Erdos basin tight gas resources reached to 10×1012m3. Sulige gas field is the typical representative of tight sandstone gas resources,it is also the largest uncompartmentalized gas fields on Chinaland. The gas field area is more than 5×104km2, resources of about 5×1012m3.The successful development of Sulige gas field has a leading and demonstration of great significance for China’s tight gas reservoir. In the development of the gas field in 2006, the rapid increase in the scale of production capacity, the natural gas production had exceed 200×108m3 in 2014. With the scale of development of the gas field,geological conditions is becoming more and more complicated.In the northern and wastern of Sulige gas field,the gas reservoir structure, microscopic characteristics, gas bearing are different form the central,and the relation between gas and water is very complex. It is difficult to effectively development of the gas field and the use of control about 1.5×1012m3 of reserves. It affects seriously the effect of productivity construction and long-term stable for the gas field.Su 54 block locates in the northwest of Sulige gas field, in the structure of the binding site of Yi-shan slope, Yi-meng uplift and Tian-huan depression. It has submitted the basic proven geological reserves of over 1000×108m3. Su 54 Block is a low porosity and low permeability sandstone lithologic gas reservoirs,this has been proved by the evaluation and development of 3 years of construction production practice. Its feature complex gas reservoirs with reservoir large lateral variations、low reserves abundance、gas and water distribution complex relationship、small-scale gas reservoir and the external power supply is weak, etc. Facing greater risk of geological block development, aiming at the main layer of the He8 to carry out fine gas reservoir description of gas in the block, sedimentary facies and reservoir distribution on the basis of the research, clear reservoir microscopic characteristics and gas level law, screened built favorable target area, it has important meaning for the construction of block capacity. At the same time, the study has important guiding significance for the use of Sulige gas field of West and North over similar trillion cubic.In this paper the author used sedimentology, reservoir geology and well logging geology theory as the instruction, integrated using of seismic, well logging, mud logging, core, testing, laboratory analysis and production performance data, and on the basis of fine stratigraphic correlation, carried out the research of micro amplitude reservoir structure, sedimentary microfacies of small layers and sand body distribution, and according to the analysis data in-depth analysised the reservoir petrological characteristics and pore structure, and carried out the gas water distribution combined with geological and dynamic,and established block three-dimensional geological model which can objectively reflect the characteristics of the gas reservoir,and then selected the Ⅰ, Ⅱ gas enrichment blocks, and estimated the reserves.Through this study obtained the following results and understanding:(1)Su 54 block stratigraphic classification standard is established, and completed the unification of the drilling strata contrast, ensure the consistency of stratigraphic classification;(2)Combined with seismic, geology, cleared about the Su54 block of He8 period overall appeared western-leaning monoclinal structure, developed more rows of northeast-southwest toward the lower nose, amplitude of 5m/km~15m/km, nose-like structure has a role in control in gas-water distribution;(3)Determined the He8 lower period in the study area is given priority to with braided river sedimentary, He8 upper period is given priority to with a meandering river, river were nearly north-south banded distribution, side beach and core beach are the most favorable gas-bearing microfacies;(4)On the basis of sand body contact relationship, divided sand body into 3 kinds,which is cut pile, docking and isolation type. He8 lower period of sand body is given priority to cut and docking, He8 upper period is given priority with isolated sand body;(5)The study area He8 reservoir rocks in the high content of quartz, mainly quartz sandstone and lithic quartz sandstone quality;Pore types mainly lithic dissolved pore, intercrystalline pore;Flake or bending sheet throat are the most common, and has the characteristics of "small pore throat, poor sorting and high displacement pressure, small contribution of throat",and exhibited strong heterogeneity characteristic;(6)Single well gas water relation mode can be divided into four types: gas water layer, gas upper water layer, gas upper gas water layer, gas water upper water layer, and the main mode is gas water layer, accounting for 74%;(7)The main controlling factors of formation water distribution are reservoir heterogeneity and micro structure, fracture(fault). The stronger the reservoir heterogeneity, the lower the tectonic location,the worse the gas saturation, fault would not conducive to the preservation of the natural gas, fault zones’ water is greater than the fault undevelopment area in He8,the eastern area with high structural position and good reservoir property, and far away large fault, is relative enrichment of gas;(8)Established the Su54 block gas enrichment region selection criteria on the main basis of energy storage coefficient of planar distribution combining with "seismic-geology-dynamic", and using this standard selected the He8Ⅰ+Ⅱ gas enrichment region area reach to 167.1 km2, volume method is used to estimate He8 Ⅰ+Ⅱ zone reserves amounted to 245.9×108m3.