At present two technical models are commonly taken in tight gas reservoir stimulation:conventional massive fracturing and SRV fracturing,but how to select a suitable fracturing model suitable for reservoir characteris...At present two technical models are commonly taken in tight gas reservoir stimulation:conventional massive fracturing and SRV fracturing,but how to select a suitable fracturing model suitable for reservoir characteristics is still a question waiting to be answered.In this paper,based on the analysis of geological characteristics and seepage mechanism of tight gas and shale gas reservoirs,the differences between stimulation philosophy of tight gas reservoirs and shale reservoirs are elucidated,and the concept that a suitable stimulation model should be selected based on reservoir geological characteristics and seepage mechanism aiming at maximally improving the seepage capability of a reservoir.Based on this concept,two fracturing design methods were proposed for two tight gas reservoirs in western Sichuan Basin:asymmetrical 3D fracturing design(A3DF)for the middle-shallow Upper Jurassic Penglaizhen Fm stacked reservoirs in which the hydraulic fractures can well match the sand spatial distribution and seepage capability of the reservoirs;SRV fracturing design which can increase fracture randomness in the sandstone and shale laminated reservoirs for the 5th Member of middle-deep Upper Triassic Xujiahe Fm.Compared with that by conventional fracturing,the average production of horizontal wells fractured by A3DF increased by 41%,indicating that A3DF is appropriate for gas reservoir development in the Penglaizhen Fm;meanwhile,the average production per well of the 5th Member of the Xujiahe Fm was 2.25×10^(4)m^(3)/d after SRV fracturing,showing that the SRV fracturing is a robust technical means for the development of this reservoir.展开更多
Stimulated Reservoir Volume(SRV)fracturing is a key technology of unconventional oil and gas exploration and development.To gain a deeper understanding of tight sandstone reservoirs and draw on the development experie...Stimulated Reservoir Volume(SRV)fracturing is a key technology of unconventional oil and gas exploration and development.To gain a deeper understanding of tight sandstone reservoirs and draw on the development experience of hydraulic fracturing,the authors conduct a large number of detailed investigations of geological characteristics in the regions that have implemented SRV fracturing.Based on the data of rock mechanics parameters,insitu stress characteristics,brittleness characteristics and natural fractures,the influencing factors of SRV fracturing in tight oil reservoirs were analyzed.The results show that the SRV fracturing is suitable for geological reservoirs with the characteristics of medium to high elastic modulus,low to medium Poisson’s ratio,low stress difference,medium to high brittleness and naturally fractured reservoirs,where natural fractures have a significant impact.Region A,a tight sandstone region,has moderate elastic modulus,low Poisson’s ratio,low ground stress difference and medium brittleness,and has the feasibility of volume fracturing.The field case of the Y325 well shows that SRV fracturing technology has obvious effect on increasing production.This technology is applicable to the Region A.展开更多
文摘At present two technical models are commonly taken in tight gas reservoir stimulation:conventional massive fracturing and SRV fracturing,but how to select a suitable fracturing model suitable for reservoir characteristics is still a question waiting to be answered.In this paper,based on the analysis of geological characteristics and seepage mechanism of tight gas and shale gas reservoirs,the differences between stimulation philosophy of tight gas reservoirs and shale reservoirs are elucidated,and the concept that a suitable stimulation model should be selected based on reservoir geological characteristics and seepage mechanism aiming at maximally improving the seepage capability of a reservoir.Based on this concept,two fracturing design methods were proposed for two tight gas reservoirs in western Sichuan Basin:asymmetrical 3D fracturing design(A3DF)for the middle-shallow Upper Jurassic Penglaizhen Fm stacked reservoirs in which the hydraulic fractures can well match the sand spatial distribution and seepage capability of the reservoirs;SRV fracturing design which can increase fracture randomness in the sandstone and shale laminated reservoirs for the 5th Member of middle-deep Upper Triassic Xujiahe Fm.Compared with that by conventional fracturing,the average production of horizontal wells fractured by A3DF increased by 41%,indicating that A3DF is appropriate for gas reservoir development in the Penglaizhen Fm;meanwhile,the average production per well of the 5th Member of the Xujiahe Fm was 2.25×10^(4)m^(3)/d after SRV fracturing,showing that the SRV fracturing is a robust technical means for the development of this reservoir.
基金The research was financially supported by National NaturalScience Foundation of China (No.51774093).
文摘Stimulated Reservoir Volume(SRV)fracturing is a key technology of unconventional oil and gas exploration and development.To gain a deeper understanding of tight sandstone reservoirs and draw on the development experience of hydraulic fracturing,the authors conduct a large number of detailed investigations of geological characteristics in the regions that have implemented SRV fracturing.Based on the data of rock mechanics parameters,insitu stress characteristics,brittleness characteristics and natural fractures,the influencing factors of SRV fracturing in tight oil reservoirs were analyzed.The results show that the SRV fracturing is suitable for geological reservoirs with the characteristics of medium to high elastic modulus,low to medium Poisson’s ratio,low stress difference,medium to high brittleness and naturally fractured reservoirs,where natural fractures have a significant impact.Region A,a tight sandstone region,has moderate elastic modulus,low Poisson’s ratio,low ground stress difference and medium brittleness,and has the feasibility of volume fracturing.The field case of the Y325 well shows that SRV fracturing technology has obvious effect on increasing production.This technology is applicable to the Region A.
