压裂气井合理试气压差的优化模型

OPTIMIZING MODEL OF THE REASONABLE GAS-TEST PRESSURE DIFFERENTIAL FOR FRACTURED GAS WELLS

在压裂气井压裂后试气过程中，选择合理的生产压差是正确评价气井产能和准确计算储层产量的关键。基于储层物性应力敏感性和水力裂缝导流能力受闭合应力变化的影响，建立了压裂气井试气压差的优化模型，并给出了求解方法。计算结果表明：在不考虑任何影响因素下，压裂气井的产量与压差存在较好的正相关性，随着压差的增加而增大；而实际试气过程中储层物性和裂缝导流能力都为动态值，随着储层流体压力降低而发生改变，产量随着压差的增加具有先增大后减小的变化特征，在最优的生产压差下存在1个产量峰值。研究结果为压裂气井试气选择合理的生产压差提供了理论基础，为建立科学合理的试气制度提供了技术保障。

Abstract： During the process of post-fracturing gas test in the fractured gas wells, the choice of the reasonable pressure differential is the key to the correct evaluation of the gas-well productivity and accurate calculation of the reservoir productions. Based on the effects and influences of the closure stress on stress sensitivity of the reservoir properties and the fracture conductivity of the hydraulic fracturing, the optimizing model of the gas-test pressure dif- ferential for the fractured gas wells is established, and moreover the solution-seeking method is presented. The cal- culation results show that if taking no account of any influence factor, there are much better correlation between the well productions and pressure differentials： the well productions increase with the pressure differentials. However, during the actual gas test, the reservoir physical properties and fracture conductivity are dynamic： change with the fluid pressure reduction and the production is characterized by first increase and then decrease with the pressure dif- ferential enhancement and moreover there is a production peak in the optimal production differential. The research results have provided a theoretical basis for choosing reasonable production pressure differential of the gas test of the fractured wells, and furthermore established a technical guarantee for the scientific and rational gas testing system. also are important theoretical value and practical significance to improve