As every engineer in the field knows, when it comes to standards, API is our go-to when focusing on oil and gas industry operations and procedures - and API 11D1 is no exception.
Let's dive into the details of API 11D1 specification and its involvement in packer design, verification and validation.
API 11D1 is a standard intended to establish guidelines for both manufacturers and end users in the selection, manufacture, design, and laboratory testing of the many types of packers available on today’s market.
API Standards and their nature
API (The American Petroleum Institute) was developed in 1919 as a standards-setting organization and is the global leader in unite experts across segments to establish, maintain, and distribute consensus standards for the oil and gas industry.
Improve safety of oil and gas operations and procedures
American Petroleum Institute (API) standards advocate proven, sound engineering and operating practices. Following these standards promotes safe, interchangeable equipment and materials from drill bits to environmental protection.
Perhaps more importantly, the standards also establish a minimum set of parameters with which the manufacturer must comply to claim conformity.
API standards allow organizations to:
- Improve operational excellence
- Ensure compliance and safe practices
- Mitigate risks in equipment failure
API 11D1 Specification Details
This specification provides requirements and guidelines for packers and bridge plugs for use in the petroleum and natural gas industry.
API 11D1 provides requirements for the functional specification and technical specification, including
- Design verification and validation
- Documentation and data control
API 11D1 is structured with the requirements for both quality control and design verification in tiered rankings. There are three grades, or levels, established for quality control and six grades (plus one special grade) for design verification.
According to API 11D1, design verification shall be performed to ensure that each packer and bridge plug design meets the manufacturer’s technical specifications.
The design verification process includes tasks such as design reviews, design calculations, comparison with similar designs, and historical records of defined operating conditions. Verification results shall be approved by a qualified person and records of the results shall become a portion of the design documentation.
There are three grades, or levels, established for quality control and six grades (plus one special grade) for design verification.
Validation grades vary from Q3 to Q1, with grade Q3 representing the minimum requirements and Q1 representing the highest level of inspection and manufacturing verification procedures.
Similarly, the six standard design-validation grades range from V6 to V1. V6 is the lowest grade, and V1 represents the highest level of testing. A special V0 grade was included to meet special acceptance criteria requirements.
Grade V6 supplier/manufacturer defined
This is the lowest grade established. The performance level in this instance is defined by the manufacturer for products that do not meet the testing criteria found in grades V0 through V5.
Grade V5 liquid test
In Grade V5, the packer must be set in the maximum inner diameter (ID) casing it is rated for at the maximum recommended operating temperature. The testing parameters require that it be set with the minimum packoff force or pressure as specified by the manufacturer.
The pressure test is performed with water or hydraulic oil to the maximum differential-pressure rating of the packer. Two pressure reversals across the tool are required, meaning it must be proved that the packer will hold pressure from both above and below. The hold periods for each test are required to be a minimum of 15 minutes long.
At the end of the test, retrievable packers must be able to be removed from the test fixture by using the procedures of its intended design.
Grade V4 liquid test + axial loads
In Grade V4, all parameters covered in Grade V5 apply.
In addition, it must be proved that the packer will hold differential pressure in combination with compression and tensile loads, as advertised in the manufacturer’s performance envelope.
Grade V3 liquid test + axial loads + temperature cycling
In Grade V3, all parameters covered in Grade V4 apply.
To achieve Grade V3 certification, the packer also must pass a temperature cycle test. In this temperature cycle test, the packer must hold the maximum specified pressure at the upper and lower temperature limits in which the packer is designed to work.
Temperature Cycle Test
The test is started at maximum temperature, as in V4 and V5. After passing this segment of the test, the temperature is allowed to cool to the minimum, and another pressure test is applied. After successfully passing the low-temperature test, the packer also must pass a differential-pressure hold after the test-cell temperature is raised back to the maximum temperature.
Grade V2 gas test + axial loads
In Grade V2, all parameters covered in Grade V4 apply, but the test medium is replaced with air or nitrogen.
A leak rate of 20 cm3 of gas over the hold period is acceptable, however, the rate may not increase during the hold period.
Grade V1 gas test + axial loads + temperature cycling
The same test parameters used in V3 apply to Grade V1, but the test medium is replaced with air or nitrogen. Similar to the V2 test, a leak rate of 20 cm3 of gas over the hold period is acceptable, and the rate may not increase during the hold period.
NEed assistance in AP1 11D1 design, validation and verification?
When it comes to API 11D1 design, validation and verification, PES has the process down.
Experience matters – our team of talented engineers has experience engineering and designing for a multitude of industries and projects ranging from Skid & HPU package design to ASME vessel design and beyond.
Packers and Bridge Plugs, ANSI/API SPECIFICATION 11D1, ISO 14310:2008 (Modified), Petroleum and natural gas industries—Downhole equipment—Packers and bridge plugs
Packer standards and classifications - PetroWiki https://petrowiki.org/Packer_standards_and_classifications
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