煤系层薄叠置，压裂作业客观上无法规避合采。作业者主观上希望合采解决单一产层、单井产量低的难题。但是，导致这一难题的内外部因素十分复杂。传统方法中无法使用渗透率定量评价合采储层损害程度，因此，提出用合采产量评价储层伤害的思路。引入以“等当气井产量”为测试基准的多储层产量伤害物理模拟系统，在储层压力温度下测试煤系气开采过程中任意层位、开采方式的产量和压力。应用表明:① 合采产层组合中任一储层伤害前后的气体流量伤害程度均可以很好地符合渗透率伤害程度，由此提出储层伤害流量法替代渗透率法评价合采产量伤害，解决了以往煤系气合采时产层长度和过流面积无法选择而无法获得渗透率的难题;② 以合采测试的流量压力为边界条件，数值模拟不同产层天然气在井筒内混合后的流动状态，从能量角度建立了煤系气合采时地层与井筒中熵产计算模型，发现气体混合能量损耗致使煤系气产量降低，提出了“气体混合伤害”的产量伤害新类型;③ 利用该系统模拟评价地层压力恒定条件下工作液伤害前后气井流量变化率，优选出了适合临兴区块煤系气合采的钻完井流体。研究结果显示，多储层产量伤害物理模拟系统能够较为系统地支撑煤系天然气开采过程储层敏感类型和程度分析、机理研究以及工作流体优选，为煤系气合采技术优化及增产措施制定提供了方法和依据。

Coal measures are thin and stacked on top of each other.It is objectively impossible to avoid a combined mining in fracturing operations.The operators subjectively hope that the combined mining can solve the problem of high yield in a single layer.However,the factors that affect the productivity of coal measure reservoirs are very complicated,and some traditional methods cannot quantitatively analyze the damage degree of combined mining.Diagnosis and prevention require a simulation system to provide the original measurement data of fluid flow characteristics.Therefore,aiming at the problem that it is impossible to measure the combined production permeability of coal measures,the physical simulation system of multi-reservoir mining damage based on “equivalent gas well production” is introduced to test the production and pressure of any layer and any mining method in the process of coal measures mining under the environment of reservoir pressure and temperature,and the idea of production damage evaluation is put forward.The application demonstrates that ① the gas flow damage before and after any reservoir damage can be well consistent with the permeability damage.Therefore,the reservoir damage flow method is proposed to replace the permeability method for production damage evaluation in order to solve the problem that the coal measures gas production layer length and flow area cannot be selected and the permeability cannot be obtained.② Taking the flow rate and pressure of commingled production test as the boundary conditions,the flow state of natural gas in different producing layers after mixing in the wellbore is numerically simulated.The calculation model of entropy production in the formation and wellbore during the commingled of coal measures gas is established based on the perspective of energy.It is found that the energy loss of gas flow leads to the decrease of gas production in coal measures,and the “gas mixing damage” is proposed as a new type of reservoir production damage.③ The flow rate method is used to evaluate the flow rate change rate of equal pressure before and after the damage of working fluid,and the suitable drilling and completion fluid for Linxing coal measure is selected.The results show that the physical simulation system of multi-reservoir gas recovery can systematically support the analysis of reservoir sensitivity types and degrees,mechanism research,and working fluid optimization during coal measure natural gas mining,providing a method and basis for the optimization of coal measure gas co-production and the formulation of measures to increase the production.

1 物理模拟系统主要功能

2 模拟测试系统典型应用实例

   2.1 煤系储层合采敏感性评价新标准的建立

   2.2 煤系气合采储层产量伤害新类型

   2.3 煤系气合采钻完井流体优化选择的依据

3 存在问题及发展方向

4 结论