郑3X煤层气井绒囊流体重复压裂控水增产试验

郑3X煤层气井水力裂缝沟通含水砂岩层，导致了气井高产水、低产气。为此，利用绒囊流体封堵含水砂岩层和原缝，重复压裂压开新缝，降低气井产水量，提高产气量。室内测试结果表明，绒囊流体暂堵煤岩裂缝承压能力21 MPa，降低砂岩水相渗透率52.67 %，伤害煤岩基质渗透率恢复值87 %，满足转向压裂和堵水的性能要求。现场配制密度0.85~0.95 g/cm3、表观黏度40~60 mPa·s的绒囊流体80 m3。当绒囊流体成功封堵含水砂岩层和原缝后，再利用活性水进行压裂。排采结果表明，重复压裂后排水期和产气期的产水量分别降低79%和68%，而产气量提高44%，表明绒囊流体在郑3X井控水增产试验成功。绒囊流体具有良好的封堵能力和控水性能，能够实现水侵煤层气井堵水压裂一体化作业，提高煤层气开发效果。

An experiment on refracturing with fuzzy-ball fluid for water control and stimulation of CBM Well Zheng 3X

In CBM Well Zheng 3X, hydraulic fractures connect water bearing sandstone formations, leading to high water production and low gas production.In this paper, fuzzy-ball fluid was used to plug water bearing sandstone formations and primary fractures, and then refracturing was carried out to create new fractures so as to decrease the water production rate of gas well while increasing its gas production rate.It was tested in laboratory.It is shown that after the application of fuzzy-ball fluid, pressure resistance of fractures in coal rocks is 21 MPa, water permeability of sandstones decreases by 52.67% and matrix permeability recovery rate of damaged coal rocks is 87%.It is demonstrated that fuzzy-ball fluid can satisfy the performance requirements for diverting fracturing and water plugging.80 m3 fuzzy-ball fluid was prepared on site, and its density and apparent viscosity were 0.85-0.95 g/cm3 and 40-60 mPa·s, respectively.After water bearing formations and primary fractures are plugged successfully by fuzzy-ball fluid, fracturing is performed by using active water.It is shown from production results that the water production rate after the refracturing drops by 79% in water drain-age period and 68% in gas production period, and gas production rate increases by 44%.Clearly, fuzzy-ball fluid is successfully applied in the experiment on the water control and stimulation of Well Zheng 3X.To sum up, fuzzy-ball fluid presents good plugging and water control properties, and it can be used for integrated water plugging and fracturing operation in watered CBM wells.