How does the 'huff and puff' operation combat the skin effect in a gas condensate reservoir?

How does the 'huff and puff' operation combat the skin effect in a gas condensate reservoir?

• A. Inject water to wash away condensate
• B. Increases production rate at once
• C. The injection of neat natural gas redissolves the condensate and displaces it into the reservoir
• D. Reduces reservoir pressure

Answer: (C)

The key idea is that huff and puff uses cyclic gas injection to relieve near-well condensate blockage by dissolving condensate back into the gas and pushing it away from the well into the reservoir. In a gas condensate reservoir, pressure drops during production cause condensate to drop out and accumulate near the wellbore, creating a skin that restricts flow. Injecting neat natural gas raises the gas phase near the well and promotes dissolution of the condensate into the flowing gas. This reduces the liquid saturation in the near-well region, lowering flow resistance, and the injected gas helps displace the dissolved condensate deeper into the reservoir during the subsequent production phase. The result is improved gas mobility and deliverability without needing to rely on removing liquid by other means. Water injection or simply pushing more oil or gas out at once wouldn’t address the condensate blockage in the same way, and lowering reservoir pressure would typically worsen condensate formation near the well.

The key idea is that huff and puff uses cyclic gas injection to relieve near-well condensate blockage by dissolving condensate back into the gas and pushing it away from the well into the reservoir. In a gas condensate reservoir, pressure drops during production cause condensate to drop out and accumulate near the wellbore, creating a skin that restricts flow. Injecting neat natural gas raises the gas phase near the well and promotes dissolution of the condensate into the flowing gas. This reduces the liquid saturation in the near-well region, lowering flow resistance, and the injected gas helps displace the dissolved condensate deeper into the reservoir during the subsequent production phase. The result is improved gas mobility and deliverability without needing to rely on removing liquid by other means. Water injection or simply pushing more oil or gas out at once wouldn’t address the condensate blockage in the same way, and lowering reservoir pressure would typically worsen condensate formation near the well.