A successful well completion is crucial for unlocking the full potential of an oil or gas well, ensuring efficient and safe production.
What is Well Completion?
Well Completion refers to the process of transforming a drilled well into a producing oil or gas well. It involves a series of operations to prepare the well for production, ensuring safe and efficient extraction of hydrocarbons.
This is the process of making a well ready for production (or injection) after drilling operations. While drilling a well can take roughly one month, the completion process is much faster. An average completion schedule for a horizontal well is ten days.
READ: ENHANCED OIL RECOVERY(EOR)
Types of Well Completions:
- Conventional Completion: Traditional method, using casing and cement.
- Unconventional Completion: Used for shale or tight gas formations, involving fracking.
- Horizontal Completion: Used for horizontal wells, accessing more reservoir area.
- Multistage Completion: Used for wells with multiple fractures or zones.
what is the purpose ?
Wells are completed so producers can recover the resources from the reservoir they have drilled.
Before it’s completed, an oil well is not active. After a well has been drilled and the drilling crew sets casing down the well and cements it in. This is basically a piece of pipe plugged downhole.
If it’s not completed, there is no way for the resources to get into the tubing and up the well.
Objectives of Well Completion:
- Maximize Hydrocarbon Recovery
- Ensure Well Integrity
- Optimize Production Rates
- Minimize Costs
- Enhance Reservoir Performance
Process of well completion
The process follows three basic steps:
The Casing is Bored: When it’s time for completion, the completion crew bores holes in the casing to allow the resources in the reservoir to flow into the wellbore and up to the surface.
The Well is Fracked: To execute the process of hydraulic fracturing (aka “fracking”), a wireline crew uses a wireline truck to run a piece of pipe connected to perforation guns downhole.
They measure where the “perf guns” are in the well bore. These guns have a shaped charge that is lined up in the pipe so they can create holes through the casing and into the formation itself.
They guns go off in stages, bottom to top. Then, the crew uses the wireline truck to pull the perf guns back out.
The Well is Propped Open: Finally, the completion crew rigs up pumping equipment and begins to pump a mixture of water, sand and a sand-like material called proppant into the well. These props open the fractures in the reservoir so the oil and gas can flow up to the surface and flowback can begin.
The step by step of Well Completion:
- Casing and Cementing: Installing steel casing and cement to secure the wellbore.
- Perforation: Creating holes in the casing to allow oil or gas flow.
- Fracturing (optional): Pumping fluid to create fractures, increasing reservoir connectivity.
- Gravel Packing (optional): Installing a gravel pack to enhance sand control.
- Well Intervention: Performing operations like coiled tubing, wireline, or snubbing
- Production Tree Installation: Installing the production tree (Christmas tree) to control the well.
- Testing and Evaluation: Assessing the well’s productivity and reservoir properties.