摘要
煤粉是煤层气水平井排采中的不利因素,影响煤层气的产能。根据沁水盆地南部樊庄区块煤层气水平井的排采数据,分析了煤粉产出特征;通过煤粉在支撑裂缝中运移的物模试验,揭示了煤粉在支撑裂缝中的运移和伤害规律;利用流体迁移规律研究装置,进一步研究了煤粉在水平井筒的流动规律,建立了煤粉运移模型。研究结果表明:煤粉主要来源为钻井过程中钻具对煤层的研磨及压裂过程中大排量携砂混合流体对裂缝煤壁的摩擦和冲刷;煤粉对支撑裂缝中导流能力伤害率达90%,且排采速度越大,出煤粉量越多;煤粉在水平井筒中运移的流型为层流流动,通过控制压力、流量和煤粉含量,可在排采初期实现对煤粉的控制。
As a disadvantage factor of drainage gas recovery in CBM horizontal well, pulverized coal usually leads to reservoir damage, pump stuck and other accidents when it transports in the fracturing propped fracture and horizontal wellbore, increasing the cost. Therefore, the coal powder output characteristic was analyzed according to the production data of Fanzhuang block in southern Qinshui basin, the migration of pulverized coal in propped fractures and the damage rule were revealed through physical model experiments on the migration of pulverized coal in propped fractures. The flow rule of pulverized coal in horizontal wellbore was further studied and the pul-verized coal migration model was established with the use of the device for research of fluid migration law. The result indicates that the main sources of pulverized coal are the drill grinding of coal seam in the process of drilling and the friction and erosion of large displacement fluid mixed with sand in coal wall cracks in the process of frac-turing;the damage rate of propped fracture diverting capacity caused by pulverized coal could reaches 90%, what’s more, the higher the velocity of production, the more the amount of coal powder;the flow pattern of migration of pulverized coal in horizontal wellbore is the laminar flow regime, the pulverized coal could be well controlled at the beginning of production by controlling the pressure, flow and pulverized coal concentration.
出处
《煤田地质与勘探》
CAS
CSCD
北大核心
2014年第3期31-35,共5页
Coal Geology & Exploration
基金
国家科技重大专项课题(2011ZX05061
2011ZX05042-001
2011ZX05034-003)
关键词
煤层气水平井
煤粉
产出
运移
支撑裂缝
水平井筒
CBM horizontal well
coal powder
output
transport
propped fracture
horizontal wellbore
