An Integrated Study of Cleanup Efficiency of Short Hydraulic Fractured Vertical Wells Using Response Surface Methodology

Nasriani, Hamid Reza; Jamiolahmady, Mahmoud; Alajmi, Ebrahim

doi:10.3997/2214-4609.20141380

Cited by 5 publications

(4 citation statements)

References 6 publications

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“…This ensures that GPL varies within the desired interval [0,100]. A full discussion on the domain change is discussed elsewhere (Nasriani and Jamiolahmady, 2018;Nasriani et al, 2014a). It is noted that calculated GPL values using RSM in new domain correctly vary in the 0 to 100% range.…”

Section: Responsementioning

confidence: 99%

“…Numerous numerical and parametric works were conducted on the FF cleanup and its failure to further study the HF operation. (Ahmed et al, 1979;Montgomery et al, 1990;Bennion et al, 2000;Mahadevan and Sharma, 2005;Jamiolahmady et al, 2009Jamiolahmady et al, , 2014Bazin et al, 2010;Gdanski and Walters, 2010;Ghahri, , 2010Ghahri et al, 2011;Nasriani et al, 2014a;Nasriani et al, 2014b;Nasriani and Jamiolahmady, 2018). Cheng (2012) highlighted that the flow of the fracturing fluid and water within the created and natural fractures has a substantial influence on the efficiency of hydraulically fractured wells.…”

Section: Introduction and Literature Reviewmentioning

confidence: 99%

“…The twelve pertinent parameters were fracture and matrix permeability, lambda, surface tension and fluid (gas and FF) mobility pertinent parameters in the fracture and matrix. As a result, more simulation sets with shorter CPU time were conducted in that study and the follow-up work (Nasriani et al, 2014a &b, Nasriani andJamiolahmady, 2018).…”

mentioning

confidence: 99%

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A systematic investigation into the flowback cleanup of hydraulic-fractured wells in unconventional gas plays

Nasriani

Jamiolahmady

Saif

et al. 2018

International Journal of Coal Geology

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This paper conducts an extensive investigation into fracture cleanup efficiency by considering several pertinent parameters instantaneously over a wide practical range. Injection, shut-in and production stages of the fracturing operation were simulated for 32 sets consisting of 113072 runs. To perform such a large number of simulation runs, a computer code was utilised to routinely read input data, implement the simulation runs and produce output data. In each set (which consists of 4096 runs), instantaneous impacts of twelve different parameters (i.e., fracture and matrix permeability, Brooks matrix capillary pressure (Pc) parameters, and Brooks-Corey relative permeability parameters) were investigated. To sample the domain of variables, full factorial experimental design (two-level FFS) was employed. The linear surface methodology was used to map the simulation output, which is the loss in gas production (GPL), compared to the clean case (i.e., 100% clean-up) after three production periods of 10, 30 and 365 days. The impact of various combinations of fracture fluid injection volume, fracture length, shut-in soaking time, matrix permeability variation range and drawdown on GPL were studied in different sets. Additionally, more simulation sets were performed to capture the impact of hysteresis, layering and mobile formation water on the clean-up efficiency. Results indicated that in line with some literature data, factors that controlled the mobility of FF inside the fracture had the most significant impact on cleanup efficiency. It was also noted that injecting high volumes of FF, into very tight formations significantly delayed clean-up and impaired gas production. The effect of varying other parameters such as extending soaking 1 2 time or increasing pressure down in such a case delivered negligible GPL improvement. Introducing hysteresis made clean-up slightly faster in all production periods. The impact of the gravity segregation was discussed in this study. Considering the layered systems, it was indicated that in the top layer, the fracture mobility coefficients were more important than the ones in the bottom layer whist capillary pressure seems to become more important in deeper layers compared to the top layers. Additionally, a slower clean-up was observed for sets with larger initial water saturation compared to those cases with immobile water saturation due to the detrimental effect of mobile water on gas production. In some cases, with significantly high values of water saturation, using chemicals (which IFT reducing agents) to reduce Pc could reduce GPL and improve cleanup efficiency. These findings contribute to the further understanding of the fracture fluid cleanup process and provide practical guidelines to achieve economically successful hydraulic fracturing operations, which are popular but expensive for tight and ultra-tight reservoirs.

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Section: Responsementioning

confidence: 99%

Section: Introduction and Literature Reviewmentioning

confidence: 99%

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A systematic investigation into the flowback cleanup of hydraulic-fractured wells in unconventional gas plays

Nasriani

Jamiolahmady

Saif

et al. 2018

International Journal of Coal Geology

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“…It was noticed that if the formation becomes tighter (smaller k m ), it results in a more substantial loss in the gas production and consequently, the cleanup procedure will become slower and vice versa. It was also concluded that if the pressure drawdown is small, the impact of Pc on the clean-up performance was more significant, a similar observation was noted once the soaking time was extended (Nasriani, 2017;Nasriani et al, 2018, 2014b, 2014a, Nasriani and Jamiolahmady, 2018a, 2018b. Nasriani et al (2018) captured the impact of injected fracture fluid volume, length of the fracture, pressure drawdown, hysteresis, layering, gravity segregation and mobility/immobility of the formation water on the post-fracturing cleanup performance.…”

Section: A N U S C R I P Tmentioning

confidence: 80%

Flowback cleanup mechanisms of post-hydraulic fracturing in unconventional natural gas reservoirs

Nasriani

Jamiolahmady

2019

Journal of Natural Gas Science and Engineering

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This work investigates the fracturing fluid cleanup mechanisms of post-hydraulic fracturing in unconventional gas formations by studying a large number of wide-ranging parameters simultaneously. In this work, different scenarios of the cleanup operation of the hydraulic fracturing process are considered. This study consists of investigating the post-fracturing cleanup operation of hydraulically fractured vertical wells (VW) and multiple fractured horizontal wells (MFHWs). Additionally, the impact of soaking time, the range of the matrix permeability, applied drawdown pressure, injected fracturing fluid (FF) volume, fracture spacing and horizontal well length has been investigated by running different sets. Results show that that the trend of the impact of relevant parameters for VWs and MFHWs are analogous excepting the matrix permeability, k m. That is, in the MFHW base reference set, the effect of matrix permeability on capillary pressure is more significant than that on fluid flow while the reverse is observed for VW. The difference in the impact of k m in VWs and MFHWs is attributed to the geometry of the fluid flow towards the production well and different well completion scheme. It is also concluded that the impact of parameters affecting the capillary pressure in the matrix is more significant for MFHWs whereas matrix and fracture mobility pertinent parameters are more important for VWs than MFHWs. As a result, larger matrix capillary pressure values are more vital in the cleanup of MFHWs because of more imbibition of FF into the matrix and subsequently lower conflict between the flow of gas and FF in the fracture. The other part of this research concentrates on the impact of IFT reducing agents on the postfracturing production in different formations. In hydraulic fracturing operations, these agents

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A Comparison of Clean-Up Efficiency of Multiple Fractured Horizontal Wells and Hydraulically Fractured Vertical Wells in Tight Gas Reservoirs

Nasriani¹,

Jamiolahmady²

2018

SPE Europec Featured at 80th EAGE Conference and Exhibition

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Hydraulic fracturing is a well-established stimulation technique especially for unconventional reservoirs. However, sometimes its performance is less than expected due to poor cleanup of the injected fracture fluid. There are publications studying the clean-up efficiency of hydraulic fractures in vertical wells, however, there is little information in this area for multiple fractured horizontal wells, MFHWs. This paper compares the fracture cleanup efficiency of a hydraulically fractured vertical well (VW) with that of multiple fractured horizontal wells (MFHWs) using numerical simulations and statistical approaches. In these simulations, twelve parameters related to fracture and matrix relative permeability and matrix capillary pressure were varied simultaneously based on the two-level full factorial experimental design statistical method. Gas production loss (GPL), as the response term, was calculated and input into Response Surface Model. In each set, the correlation between parameters and GPL was established and compared to investigate the post-fracturing cleanup efficiency. Results show that the direction of impact of parameters for VW and MFHW are similar except for the matrix permeability, Km. This difference is attributed to the flow geometry and how the well has been completed. This observation underlines that in MFHWs, the cleanup mechanism and the sequences of the importance of pertinent parameters could be different from those of the VWs. Results also indicate that matrix Book's type capillary pressure pertinent parameters are more important in the MFHW sets whilst Corey type relative permeability parameters are more important in VWs. These observations suggest that having a higher capillary pressure is more important in MFHWs because it results in more FF imbibition into the matrix and consequently less resistance to gas flow within the fracture. Several MFHW models with different number of fractures were constructed, which demonstrated that although the impact on well productivity is significant, its impact on clean-up performance was minimal. These results improve our understanding of VWs and MFHWs clean-up and design of such costly operations.

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An Integrated Study of Cleanup Efficiency of Short Hydraulic Fractured Vertical Wells Using Response Surface Methodology

Cited by 5 publications

References 6 publications

A systematic investigation into the flowback cleanup of hydraulic-fractured wells in unconventional gas plays

A systematic investigation into the flowback cleanup of hydraulic-fractured wells in unconventional gas plays

Flowback cleanup mechanisms of post-hydraulic fracturing in unconventional natural gas reservoirs

A Comparison of Clean-Up Efficiency of Multiple Fractured Horizontal Wells and Hydraulically Fractured Vertical Wells in Tight Gas Reservoirs

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