Derivation and Analysis on Productivity Formula in Low Permeability Gas Reservoir Fracturing Well Development
Tan Miao ,Zhang Zhiquan,Han Xin,Chen Fei(Yangtze University Oil Engineering College,Jingzhou,Hubei, 434023,China)
Lowpermeability gas reservoirs are characterized by lowporosity and permeability of matrix,influence of slippage effect and start- up pressure gradient is more outstanding. In order to predict low permeability gas reservoir capacityaccuratelyand develop lowpermeabilitygas reservoirs reasonablyand effectively,it is necessarytofurther make clear influence of slippage effect and start- up pressure gradient on low permeability gas well productivity. Analyzed are various inflow dynamic curves under the conditions of different start- up pressure gradients and slippage effects and the influence ofslippage effect on gas well productivityunder the conditions ofdifferent matrixpermeability. The results show that fracturing gas well productivity will decrease as start-up pressure gradient increases,but the productivity will decrease significantly and the productivity will increase as slippage effect increases. For very low permeability gas reservoirs,the influence ofthe slippage effect shall not be neglected in lowpressure conditions.