Study Of Shale Gas Production And Reserve Employment Law Produced By Fractured Horizontal Well

There is a significant difference of the microcosmic pore and throat between shale and conventional sand gas reservoir.The more complex form makes the flow mechanism of shale more complex and unique.The previous studies mainly focus on mechanism model but when it comes to engineering using,it should put more emphasis on production influencing factors and reserve employment factors caused by engineering factors.However,there is little of this kind of studied,so it is necessary to conduct this kind of study to guide engineering plan and production system.Through investigating of the mature method of establishing shale gas multi-fractured horizontal well model,it is decided to use LGR and sub-cell methods to build the basic grid model to simulate the transient flow phenomenon of shale gas.Absorbed gas model use Langmuir isothermal curve and use tracer to trace the production of absorbed gas.The study results of production influencing law show that of all the fracture parameters,the increase of half fracture length,the decrease of distance between two fractures and the increase of fracture's non-dimensional flow conductivity will bring an increasing to the initial production and cumulative production,but the increasing speed is slower and slower.The change of half fracture length and fracture's non-dimensional flow conductivity make more significant influence on the initial production than cumulative production.The change of the distance between two fractures makes less significant influence on the initial production than cumulative production.Of all the reservoir characteristics,the increase of permeability,the increase of porosity,the increase of sigma and the increase of formation pressure index will bring an increasing to the initial production and cumulative production,and the initial absorbed gas and free gas ratio and the different form of adsorption curve have little influence on the initial production and cumulative production.The change of permeability,sigma and formation pressure index make more significant influence on the initial production than cumulative production.The study results of the law of reserve employment show absorbed gas takes a little proportion in the production rate and cumulative production,especially in the beginning to the middle of the production period and its production can be ignored.There is a lot of reserve between two hydraulic fractures,so if the fracture technology and economy is feasible the more intensive the fractures the better.The reserve out of the tip of the fractures employed little in the beginning of the production,but because of the high mobility of gas,when the production period is long enough,the outer area's reserve can be employed well.