宋金星,史俊可,刘建壮.团聚型压裂液对煤粉运移的影响及作用机理[J].煤田地质与勘探,2022,50(2):48−54. DOI: 10.12363/issn.1001-1986.21.07.0370
引用本文: 宋金星,史俊可,刘建壮.团聚型压裂液对煤粉运移的影响及作用机理[J].煤田地质与勘探,2022,50(2):48−54. DOI: 10.12363/issn.1001-1986.21.07.0370
SONG Jinxing,SHI Junke,LIU Jianzhuang.Effects of the agglomerated fracturing fluid on the transportation of pulverized coal and its mechanism[J].Coal Geology & Exploration,2022,50(2):48−54. DOI: 10.12363/issn.1001-1986.21.07.0370
Citation: SONG Jinxing,SHI Junke,LIU Jianzhuang.Effects of the agglomerated fracturing fluid on the transportation of pulverized coal and its mechanism[J].Coal Geology & Exploration,2022,50(2):48−54. DOI: 10.12363/issn.1001-1986.21.07.0370

团聚型压裂液对煤粉运移的影响及作用机理

Effects of the agglomerated fracturing fluid on the transportation of pulverized coal and its mechanism

  • 摘要: 排采过程中,煤粉随着运载流体在支撑裂缝中运移,容易导致裂隙堵塞,造成煤储层渗透率和支撑裂缝导流能力的降低,为探究团聚型压裂液性质对煤粉运移产生的影响及作用机理,选取准南煤田乌鲁木齐河东矿区煤样为研究对象,以蒸馏水、活性水压裂液(1.5%KCl)、团聚型压裂液(1.5%KCl+0.05%AN)为运载流体,通过单相流驱替状态下煤粉产出物理模拟实验,获取驱替流速为100、200、300 mL/min时的煤粉产出量和支撑裂缝导流能力伤害率,结果表明:气体驱替流速为100 mL/min时3种运载流体煤粉累计产出量均呈现线性增长趋势,支撑裂缝的导流能力伤害率变化范围较小(0.6%~8.1%);气体驱替流速为200 mL/min时,随着支撑裂缝中煤粉沉积,运移通道缩小,各运载流体出粉量先达到最大值随后减少,团聚型压裂液裂缝导流能力伤害率较小,其导流能力伤害率累计值分别与蒸馏水和活性水压裂液导流能力伤害率相差分别达到24.4%和3.1%;气体驱替流速为300 mL/min时:煤粉出粉量达到最大值的时间提前,运载流体为团聚型压裂液支撑裂缝导流能力伤害率最小,其导流能力伤害率累计值与蒸馏水和活性水压裂液导流能力伤害率相差分别达到64.8%和14.9%。因此驱替流速较低时,煤粉产出量较少且导流能力伤害率较低。结合静置沉降实验和直剪实验,揭示了团聚型压裂液对煤粉运移的作用机理:煤粉运移过程中团聚型压裂液能够通过表面活性剂的亲水基和亲油基改变溶液与煤粉界面状态,增强煤粉润湿性,使煤粉颗粒在运移过程中聚集沉降;通过增加其液桥力使黏聚力增大,抑制沉降的煤粉发生相对移动,从而减少悬浮煤粉颗粒的数量,有效降低煤粉产出量和支撑裂缝导流能力伤害率,进而减少卡钻、修井的发生概率,实现对煤粉的有效防控。

     

    Abstract: During the drainage process, the pulverized coal moves with the carrier fluid in supporting fractures, resulting in the blockage of the fractures and then a decrease in the permeability of the coal reservoir and the conductivity of the supporting fractures. For the purpose of exploring the effects of the properties of the agglomerated fracturing fluid on the transportation of pulverized coal and its mechanism, the coal samples from Urumqi Hedong Mining Area in southern Junggar Basin coalfield are selected as the research object, with distilled water, active water fracturing fluid(1.5%KCl), and agglomeration fracturing fluid(1.5%KCl+0.05%AN) as the carrier fluids. Through the physical simulation experiment of pulverized coal production under the single-phase flow displacement state, the production of pulverized coal and the damage rate of supporting fracture conductivity at the displacement flow rate of 100 mL/min, 200 mL/min, and 300 mL/min are obtained. The results show that when the gas displacement flow rate is 100 mL/min, the cumulative output of pulverized coal of the three carrier fluids all show a linear growth trend, and the damage rate of the fracture conductivity varies within a small range (0.6%-8.1%). At the gas displacement flow rate of 200 mL/min, as the pulverized coal deposits in the supporting fractures, the migration channel shrinks, so that the powder output of each carrier fluid first reaches the maximum value and then decreases. The damage rate of the fracture conductivity of the agglomerated fracturing fluid is low. The difference between the cumulative damage rate of its conductivity and the damage rate of the conductivity of distilled water and active water fracturing fluid are 24.4% and 3.1%, respectively. At the gas displacement flow rate of 300 mL/min, the time when the output of pulverized coal reaches the maximum value is advanced. The fracture conductivity damage rate of the agglomerated fracturing fluid is the lowest, and the difference between the cumulative damage rate of its conductivity and the damage rate of conductivity of distilled water and active water fracturing fluid is 64.8% and 14.9%, respectively. Therefore, with a lower displacement flow rate, the output of pulverized coal is less and the damage rate of conductivity is lower. Through the static settlement experiment and the direct shear experiment, the mechanism of the agglomerated fracturing fluid on the migration of pulverized coal is revealed. During the migration of pulverized coal, by using the agglomerated fracturing fluid, the interface state between the solution and the pulverized coal is changed through the hydrophilic and lipophilic groups of surfactants, and the wettability of the pulverized coal is enhanced, resulting in the aggregation and settlement of pulverized coal particles. By increasing the liquid bridge force, the cohesive force is increased, and the relative movement of the settled coal is inhibited, thereby reducing the number of suspended coal particles. The output of pulverized coal and the damage rate of the conductivity of supporting fractures are effectively reduced, thus reducing the probability of sticking and workover, and realizing effective prevention and control of pulverized coal.

     

/

返回文章
返回