INTRODUCTION Hydraulic fracturing occurs when high pressure fluids primarily consisting of water and sand are pumped at high pressure into subsurface formations,typically shale that contains natural gas and/or oil.The...INTRODUCTION Hydraulic fracturing occurs when high pressure fluids primarily consisting of water and sand are pumped at high pressure into subsurface formations,typically shale that contains natural gas and/or oil.The high pressure fluid causes the rock to fracture.The new fractures increase the surface area of the shale and better interconnect previously existing fractures,allowing more natural gas and/or oil to be pumped from the formation.Modern hydraulic fracturing,referred to as“fracking,”is an evolving technology that largely began after 2000 and has significantly increased natural gas production in the United States in the past five years with corresponding decreases in natural gas prices.展开更多
为了解决部分煤矿在高瓦斯、主采煤层煤质碎软的情况下,常规水力压裂煤层增透技术存在压裂不均衡、覆盖范围小、定向长钻孔难以在煤层内成孔的问题,研究了“定向长钻孔+分支孔”瓦斯抽采钻孔分段水力压裂技术。利用RFPA2D-Flow软件对分...为了解决部分煤矿在高瓦斯、主采煤层煤质碎软的情况下,常规水力压裂煤层增透技术存在压裂不均衡、覆盖范围小、定向长钻孔难以在煤层内成孔的问题,研究了“定向长钻孔+分支孔”瓦斯抽采钻孔分段水力压裂技术。利用RFPA2D-Flow软件对分段压裂关键参数进行了计算,并在山西某煤矿回风巷道施工定向长钻孔402 m,开分支孔9个,进行了4次分段水力压裂,合计压裂注水37.2 m 3,分析了分段水力压裂技术的适用情况。研究结果表明,瓦斯抽采钻孔压裂效果明显,为提高瓦斯抽采效果创造了条件。展开更多
Deep shale gas exploration and production in Fuling(Sichuan Basin,SW China)are confronted with hydraulic fracturing challenges owing to high stress,high fracture pressure,low pump rate and proppant concentration,as we...Deep shale gas exploration and production in Fuling(Sichuan Basin,SW China)are confronted with hydraulic fracturing challenges owing to high stress,high fracture pressure,low pump rate and proppant concentration,as well as high closing pressure in deep strata.This study focused on the mechanical properties of shale core samples from Fuling through high-temperature triaxial rock mechanical tests and in-situ stress tests based on the Kessel effect of acoustic emission.Their mechanical property var-iations with depth were delineated using brittleness index calculated via simulating different depths and different confining pressures for the samples.The results showed that several parameters of deep shale reservoirs,i.e.brittleness index,fracture density,performance of self-propping,and flow conductivity,are lower than that of shale reservoirs with moderate burial depth.Thus,the current operating pressure in deep shale reservoir stimulation should be taken full advantage of,rather than channeling the focus on the propagation of fracture length.The objective is to increase the complexity of the near-hole fracture network for enhancing self-propping and flow conductivity of the fractures.This can be achieved by reducing the number of perforation clusters and cluster spacing,adopting variable-rate fracturing,decreasing proppant size,increasing sand volume,and optimizing the fracturing parameters.A field application showed that,compared with the neighboring wells,the test well had larger drainage area,doubling the gas yield.展开更多
文摘INTRODUCTION Hydraulic fracturing occurs when high pressure fluids primarily consisting of water and sand are pumped at high pressure into subsurface formations,typically shale that contains natural gas and/or oil.The high pressure fluid causes the rock to fracture.The new fractures increase the surface area of the shale and better interconnect previously existing fractures,allowing more natural gas and/or oil to be pumped from the formation.Modern hydraulic fracturing,referred to as“fracking,”is an evolving technology that largely began after 2000 and has significantly increased natural gas production in the United States in the past five years with corresponding decreases in natural gas prices.
文摘为了解决部分煤矿在高瓦斯、主采煤层煤质碎软的情况下,常规水力压裂煤层增透技术存在压裂不均衡、覆盖范围小、定向长钻孔难以在煤层内成孔的问题,研究了“定向长钻孔+分支孔”瓦斯抽采钻孔分段水力压裂技术。利用RFPA2D-Flow软件对分段压裂关键参数进行了计算,并在山西某煤矿回风巷道施工定向长钻孔402 m,开分支孔9个,进行了4次分段水力压裂,合计压裂注水37.2 m 3,分析了分段水力压裂技术的适用情况。研究结果表明,瓦斯抽采钻孔压裂效果明显,为提高瓦斯抽采效果创造了条件。
文摘Deep shale gas exploration and production in Fuling(Sichuan Basin,SW China)are confronted with hydraulic fracturing challenges owing to high stress,high fracture pressure,low pump rate and proppant concentration,as well as high closing pressure in deep strata.This study focused on the mechanical properties of shale core samples from Fuling through high-temperature triaxial rock mechanical tests and in-situ stress tests based on the Kessel effect of acoustic emission.Their mechanical property var-iations with depth were delineated using brittleness index calculated via simulating different depths and different confining pressures for the samples.The results showed that several parameters of deep shale reservoirs,i.e.brittleness index,fracture density,performance of self-propping,and flow conductivity,are lower than that of shale reservoirs with moderate burial depth.Thus,the current operating pressure in deep shale reservoir stimulation should be taken full advantage of,rather than channeling the focus on the propagation of fracture length.The objective is to increase the complexity of the near-hole fracture network for enhancing self-propping and flow conductivity of the fractures.This can be achieved by reducing the number of perforation clusters and cluster spacing,adopting variable-rate fracturing,decreasing proppant size,increasing sand volume,and optimizing the fracturing parameters.A field application showed that,compared with the neighboring wells,the test well had larger drainage area,doubling the gas yield.
