Title: Gas Condensate Damage in Hydraulically Fractured Wells
Abstract: Gas Condensate Damage in Hydraulically Fractured Wells Reza Rostami Ravari; Reza Rostami Ravari National Iranian Oil Company Search for other works by this author on: This Site Google Scholar Robert A. Wattenbarger; Robert A. Wattenbarger Texas A&M University Search for other works by this author on: This Site Google Scholar Mazher Hassan Ibrahim Mazher Hassan Ibrahim Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Asia Pacific Oil and Gas Conference and Exhibition, Jakarta, Indonesia, April 2005. Paper Number: SPE-93248-MS https://doi.org/10.2118/93248-MS Published: April 05 2005 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Ravari, Reza Rostami, Wattenbarger, Robert A., and Mazher Hassan Ibrahim. "Gas Condensate Damage in Hydraulically Fractured Wells." Paper presented at the SPE Asia Pacific Oil and Gas Conference and Exhibition, Jakarta, Indonesia, April 2005. doi: https://doi.org/10.2118/93248-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Asia Pacific Oil and Gas Conference and Exhibition Search Advanced Search AbstractThe work in this paper is a result of a problem encountered in producing a low permeability formation from a hydraulically fractured well in South Texas. The well was producing from a tight gas condensate reservoir and there was concern about damaging the well if the wellbore pressure fell below the dew point. However, it turned out that condensate damage was not a problem. Lower wellbore pressures only resulted in higher rates.This study used compositional reservoir simulation to model production for three situations; all having low permeability and hydraulic fractures. The simulation results verify what was observed in the field: lower wellbore pressure yields higher production rates.Although some condensatedamage was observed below the dew point, none of the cases showed that lower wellbore pressures led to worse overall well performance.Even for the case of a very rich gas condensate, the optimum conditions correspond to the lowest pwf.The results of this research may be a step forward in improving the management of gas condensate reservoirs by understanding the mechanics of liquid build-up.Although some wells may be "ruined" by low wellbore pressures, this was not evident in the cases in our work.The hydraulic fracturing seemed to reduce the condensate damage effect.IntroductionThe pressure and flow rate behavior of a gas condensate reservoir is distinctly different from the behavior of a solution gas drive reservoir. The producing rate is not only affected by the pressure gradient, but is also a more complex function of the actual value of the flowing bottomhole pressure[1]. Radial compositional simulation models were often used to investigate the problem of productivity loss [2, 3–7]. These models clearly show that the loss in productivity was due to liquid dropout near the wellbore. This so-called condensate blocking (increase in condensate saturation around the wellbore) reduces the effective permeability to gas and results in a rapid decline well productivity once the near wellbore pressure drops below the dew point.El-Banbi et al.[8] showed that the well productivity of vertical wells in a moderately rich gas condensate reservoir initially decreased rapidly and then increased as the reservoir was depleted. This phenomenon was explained by compositional simulation of a radial model. Initially, because of high condensate saturation in the ring (areas around the wellbore) the effective permeability to gas decreases severely, thereby reducing gas productivity. As the average reservoir pressure continues to decline, the entire reservoir will fall below the dew point pressure. Consequently, the gas flowing into the ring becomes leaner, causing the condensate saturation in the ring to decrease. This increases the effective permeability to gas and causes the gas productivity to increase.Hydraulic fracturing has been proven to be one of the most effective techniques for improving the productivity of gas condensate reservoirs [9–14]. Stimulation reduces the pressure drawdown and thus leads to less liquid dropout. On top of that, non-Darcy effects are reduced and the well will suffer lower productivity decrease when liquid blocking occurs. Distribution of the liquid condensate around the fracture can alleviate or greatly soften the impact of hydraulic fracturing on gas production. This flow impairment along the fracture surface in the reservoir is commonly referred to as fracture face skin effect.The current work is a result of experience encountered in producing Smith #1, a hydraulically fractured well in South Texas. The well was producing a tight gas condensate reservoir and the flowing bottomhole pressure, pwf, was above the dew point pressure. There was concern about what would happen if pwf dropped below the dew point pressure. Then, it was observed in the field that the more pwf was lowered below the dew point pressure, the higher gas rate was obtained.Nothing bad happened.Most previous work has tackled the problem from a radial model perspective. Since in many tight gas wells, long-term linear flow occurs during depletion and long-term production is more nearly a constant pressure condition[15], this work simulated flow into a hydraulic fracture at constant flowing bottomhole pressure. Keywords: reservoir, upstream oil & gas, fracture, bottomhole pressure, saturation, production monitoring, reservoir surveillance, flow in porous media, hydraulic fracture, production rate Subjects: Hydraulic Fracturing, Well & Reservoir Surveillance and Monitoring, Reservoir Fluid Dynamics, Formation Evaluation & Management, Unconventional and Complex Reservoirs, Flow in porous media, Gas-condensate reservoirs This content is only available via PDF. 2005. Society of Petroleum Engineers You can access this article if you purchase or spend a download.