Chemical Treatment To Mitigate Condensate and Water Blocking in Gas Wells in Carbonate Reservoirs

Ahmadi, Mohabbat; Sharma, Mukul M.; Pope, Gary A.; Torres, David E; Mcculley, Corey; Linnemeyer, Harold

doi:10.2118/133591-pa

Cited by 27 publications

(14 citation statements)

References 48 publications

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“…The phase behavior of gas/condensate mixtures has been studied and reported by many researchers (Ahmed 1988;Bang 2005;Sarkar et al 1991). The existence of alcohols or water within the condensate bank increases the complexity of the phase behavior of the reservoir fluids (Kokal et al 2000;Pedersen and Milter 2004).…”

Section: Use Of Solventsmentioning

confidence: 99%

Mitigation of the Effects of Condensate Banking: A Critical Review

Sayed

Al-Muntasheri

2016

SPE Production &Amp; Operations

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With production from gas/condensate reservoirs, the flowing bottomhole pressure of the production well decreases. When the flowing bottomhole pressure decreases below the dewpoint, condensate accumulates near the wellbore region and forms a condensate bank. This results in a loss of productivity of both gas and condensate, which becomes more serious in intermediate-and low-permeability gas/condensate reservoirs, where the condensate bank reduces both the gas permeability and the well productivity.Several techniques have been used to mitigate this problem. These methods include:• Use of solvents and wettability-alteration chemicals to reduce the impact of condensate blockage • Gas cycling and injection of nitrogen and supercritical carbon dioxide as pressure-maintenance methods • Drilling horizontal wells, hydraulic fracturing, and acidizing to improve the well productivity Gas cycling aims to keep the reservoir pressure greater than the dewpoint pressure to reduce the condensation phenomena. The limited volumes of gas that can be recycled in the reservoir can hinder the application of this method. For an ideal gas-cycling process, the volume of the gas injected into the reservoir will be larger than the total gas that can be produced from such a reservoir. Other approaches are the drilling of horizontal wells and hydraulic fracturing, during which the pressure drop around the wellbore region is lowered to allow for a longer production time, with only single-phase gas flow to the wellbore. These approaches are costly because they require drilling rigs. Another technique is the use of solvents, which shows good treatment outcomes, but the durability is a questionable issue in these treatments. Moreover, wettability alteration needs to be approached very carefully so as not to cause permanent damage to the reservoir. The use of fluorinated polymers and surfactants dissolved in alcohol-based solvents for wettability-alteration treatments was reported in many studies.Each method has its own advantages and disadvantages, and can be applied under certain conditions. This paper presents all of these methods, along with their advantages and disadvantages and description of some of their field applications and case studies.

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Section: Use Of Solventsmentioning

confidence: 99%

Mitigation of the Effects of Condensate Banking: A Critical Review

Sayed

Al-Muntasheri

2016

SPE Production &Amp; Operations

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“…Liquid accumulation around producing wells is one of the main causes of productivity decline in gas reservoirs [1,2]. As reservoir rocks tend to be strongly liquid-wet [3], the liquid phase exhibits relatively low mobility in gas-liquid flows, leading to liquid buildup.…”

Section: Introductionmentioning

confidence: 99%

Pore-Scale Analysis of Condensate Blockage Mitigation by Wettability Alteration

Reis

Carvalho

2020

Energies

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Liquid banking in the near wellbore region can lessen significantly the production from gas reservoirs. As reservoir rocks commonly consist of liquid-wet porous media, they are prone to liquid trapping following well liquid invasion and/or condensate dropout in gas-condensate systems. For this reason, wettability alteration from liquid to gas-wet has been investigated in the past two decades as a permanent gas flow enhancement solution. Numerous experiments suggest flow improvement for immiscible gas-liquid flow in wettability altered cores. However, due to experimental limitations, few studies evaluate the method’s performance for condensing flows, typical of gas-condensate reservoirs. In this context, we present a compositional pore-network model for gas-condensate flow under variable wetting conditions. Different condensate modes and flow patterns based on experimental observations were implemented in the model so that the effects of wettability on condensing flow were represented. Flow analyses under several thermodynamic conditions and flow rates in a sandstone based network were conducted to determine the parameters affecting condensate blockage mitigation by wettability alteration. Relative permeability curves and impacts factors were calculated for gas flowing velocities between 7.5 and 150 m/day, contact angles between 45° and 135°, and condensate saturations up to 35%. Significantly different relative permeability curves were obtained for contrasting wettability media and impact factors below one were found at low flowing velocities in preferentially gas-wet cases. Results exhibited similar trends observed in coreflooding experiments and windows of optimal flow enhancement through wettability alteration were identified.

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“…For hydraulic fracturing technology, it is difficult to recover the used fracturing fluid after injection into the formation. If it stays in the formation, it will block the pore canal and form seepage resistance at the staying place, which will affect the oil displacement effect, and it will also pollute the formation and form secondary pollution [16,17]. For CO 2 flooding, the process of transporting CO 2 will cause structural damage and corrosion of pipelines, and gas channeling will occur during the oil displacement process, reducing the sweep efficiency [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Effect of ASP Flooding on Improving Oil Recovery in Low Permeability Reservoirs Based on a Partial Quality Tool

Huang

et al. 2020

Processes

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In order to solve the problem of the poor oil displacement effect of high molecular weight alkali/surfactant/polymer (ASP) solution in low permeability reservoirs, Daqing Oilfield uses a partial quality tool to improve the oil displacement effect in low permeability reservoirs. In the formation, the partial quality tool degrades the polymer through active shearing action, reducing the molecular weight of the polymer, to improve the matching degree to the low permeability oil layer and the oil recovery. In order to study the ability of the partial quality tool to improve the oil displacement effect, the matching degree of high molecular weight ASP solution to low permeability cores is studied, and the ability of quality control tools to change the molecular weight is studied. Then, experimental research on the pressure and oil displacement effect of high molecular weight ASP solution before and after the actions of the partial quality tool is carried out. The results show that ASP solutions with molecular weights of 1900 × 104 and 2500 × 104 have a poor oil displacement effect in low permeability reservoirs. After the action of the partial quality tool, the injection pressure is reduced by 5.22 MPa, and the oil recovery is increased by 7.79%. The injection pressure of the ASP solution after shearing by the partial quality tool is lower than that of the ASP solution with the same molecular weight and concentration without shearing, but the oil recovery is lower. On the whole, the use of the partial quality tool can obviously improve the oil displacement effect in low permeability reservoirs.

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Chemical Treatment To Mitigate Condensate and Water Blocking in Gas Wells in Carbonate Reservoirs

Cited by 27 publications

References 48 publications

Mitigation of the Effects of Condensate Banking: A Critical Review

Mitigation of the Effects of Condensate Banking: A Critical Review

Pore-Scale Analysis of Condensate Blockage Mitigation by Wettability Alteration

Experimental Study on the Effect of ASP Flooding on Improving Oil Recovery in Low Permeability Reservoirs Based on a Partial Quality Tool

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