JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III WELL COMPLETION, TESTING AND SERVICING Previous Question Paper (August/September - 2021 - R18)

The main purpose of development wells is to exploit a proven hydrocarbon reservoir by establishing a production path from the reservoir to the surface. These wells are drilled within the boundaries of a discovered field to maximize recovery, maintain reservoir pressure, or efficiently drain the reservoir based on the established geological model.

Types of development wells include:

• Production Wells: Drilled to extract oil or gas from the reservoir to the surface.
• Injection Wells: Used to inject fluids such as water, gas, or steam into the reservoir to maintain pressure and improve the recovery factor of hydrocarbons.
• Infill Wells: Drilled between existing production wells to tap into bypassed pay zones or to increase the drainage efficiency of the reservoir.
• Observation Wells: Drilled to monitor reservoir pressure, fluid contacts, and saturation changes over time without producing fluids.

A conventional single-zone completion is the simplest method of completing a well, where a single reservoir interval is produced through one tubing string. The completion assembly typically consists of a production packer, a landing nipple, and a production tubing string.

The configuration functions as follows:

• Production Packer: Set above the producing zone to isolate the annulus between the tubing and the casing, preventing fluid communication and protecting the casing from corrosive well fluids.
• Production Tubing: The conduit through which reservoir fluids flow to the surface.
• Landing Nipple: Installed in the tubing string to allow for the placement of flow control devices like plugs or chokes.
• Perforations: The casing and cement are perforated across the target zone to allow reservoir fluids to enter the wellbore.

Visually, the arrangement shows the casing string extending to the total depth, with the production tubing suspended inside. The packer is anchored against the casing wall just above the perforated interval, ensuring that all produced fluids are directed solely into the tubing string while the casing-tubing annulus remains filled with a completion fluid.