In the oil and gas industry, plug and perforating operations, more commonly referred to as plug and perf, are a common well completion method. But if you’re new to plug and perf, you probably have lots of questions about how it works and why it’s used. Here are answers to some frequently asked questions to help you learn the basics of this important wireline service.
What Is Plug and Perf?
Plug and perf refers to using wireline to set bridge plugs and perforate casing in a single trip in the well. It allows multiple hydrocarbon zones to be isolated and completed selectively without expensive cement jobs. The wireline crew lowers specialized guns armed with shaped perforating charges downhole on wire. When the guns are positioned at the depth you want perforated, the charges blast holes through the casing and cement into the formation behind it. This allows oil or gas to flow in.
Once the zone is perforated, the guns are repositioned higher and wireline sets a bridge plug. The bridge plug seals off the lower perforations. Then the next zone can be safely perforated without communication behind pipe. This sequence repeats section by section until all target zones are perforated and isolated with plugs.
Why Is Plug and Perf Used?
The main reason to use plug and perf is to save time and costs compared to cementing. Cementing takes multiple steps to pump cement plugs before and after each zone. Wireline can perforate and isolate zones in one trip. Plugs can also be set more precisely compared to cement top jobs. And zones can be evaluated after perforating before completing them. Plug and perf reduces risks and provides flexibility.
How Are Target Zones Identified?
Typically, a suite of wireline logs will be run first to analyze the well and identify prospective zones for perforating. This may include an array of resistivity, porosity, gamma ray, neutron, and sonic logs. Image logs are also often used to actually see geological features and pick zones. Production logging after perforating provides flow contribution data to optimize completions.
What Types of Bridge Plugs Are Used?
There are a variety of wireline bridge plug designs to match different well conditions and requirements:
- Retainer plugs can be set as permanent barriers.
- Retrievable bridge plugs can later be milled out if needed.
- Composite plugs are lightweight and easy to mill.
- Cast iron and metal plugs provide robust seals and strength.
The right plug is selected based on temperature, pressure, wellbore size, and planned duration. Your wireline engineer will recommend the optimal plug for each situation.
The best way to learn more about how plug and perf can save you time and money is to talk to an expert. Reach out to a knowledgeable wireline provider, like Renegade Wireline Services, and request a consultation. Ask plenty of questions and discuss options for your next well. With the right plug and perf design, you can efficiently complete multiple zones through casing and reduce completion costs.
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