API 7CW 2020 pdf download.Casing Wear Tests.
1 Scope It is the intent of this standard to provide a method by which results will be reproducible, under a specified set of conditions, for conducting tests that determine casing wear due to rotation of drill stem elements. This standard is intended to be used in a laboratory environment and is not intended for use in the field during operations. The testing requirements in this standard are not represented at well conditions. This standard is divided into four major areas: machine apparatus, procedures, materials, and reporting. This standard will not address the significance of specific data values. It is the responsibility of the user of this standard to establish the appropriate test data values that are acceptable based on their respective application, operational limitations, and safety practices. 2 Normative References The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. API Manual of Petroleum Measurement Standards Chapter 10.4, Determination of Water and/or Sediment in Crude Oil by the Centrifuge Method (Field Procedure) API Recommended Practice 13B-1, Recommended Practice for Field Testing Water-Based Drilling Fluids API Recommended Practice 19C, Measurement of Properties of Proppants Used in Hydraulic Fracturing and Gravel- Packing Operations API Specification 5CT, Specification for Casing and Tubing API Specification 5DP, Specification for Drill Pipe 3 Terms, Definitions, and Abbreviations 3.1 Terms and Definitions For the purposes of this document, the following definitions apply. 3.1.1 asperity Protuberance in the small-scale topographical irregularities of a solid surface. 3.1.2 axial friction factor Ratio of frictional force and contact force between the test specimen and the casing while sliding (not rotating).
3.1.4 coefficient of friction Dimensionless ratio of the friction force between two bodies to the normal force pressing these bodies together. 3.1.5 contact pressure Lateral-load applied by the test specimen to the casing divided by the area of contact. NOTE Since the lateral-load is constant during a wear test, the contact pressure decreases as the wear groove deepens and widens during the wear test. 3.1.6 contact pressure threshold Minimum pressure exerted by the test specimen on the inside casing wall that will produce wear; a more definitive predictor of wear than the “Wear Factor”. NOTE Factors that determine contact pressure threshold include wear groove width, wear groove depth, and the lateral-load of the test specimen on the casing. 3.1.7 critical wear groove depth Wear groove depth when the wear grove width is equal to the test specimen diameter. 3.1.8 drill stem element test specimen Tool joint test specimen. 3.1.9 field-ready Test specimen looks like and has the same surface finish as an equivalent material would be received at the well site. 3.1.10 galling Wear mechanism with the wear debris described as flakes. 3.1.11 grinding Wear mechanism with the wear debris described as a powder. 3.1.12 lateral-load (side-load) Contact force of the test specimen against the casing specimen divided by the net length of the hardband or material coating on the test specimen. 3.1.13 machining Wear mechanism with the wear debris described as chips.
3.1.17 polishing Wear mechanism with the wear debris described as a fine powder. 3.1.18 rotational friction factor Ratio of frictional force and contact force between the test specimen and the casing while rotating. 3.1.19 side-load (lateral-load) Contact force of the test specimen against the casing specimen divided by the net length of the hardband or material coating on the test specimen. 3.1.20 sliding distance Distance traveled by a point on the periphery of the test specimen as it contacts the inner casing wall. 3.1.21 specific energy Energy required to remove one cubic inch of material from one foot of the inner casing wall, lb f -in. per cubic in. 3.1.22 surface finish Final manufactured or machined exterior evaluated by a mean roughness index number, R a . 3.1.23 surface roughness Geometrical characteristics of the surface that may include macro-deviations, surface waviness, and micro- irregularities. 3.1.24 surface roughness number (R a ) Represents the average departure of the surface from perfection measured along a line, running at a right angle to the general direction of tool marks on the surface. NOTE Typically expressed in units of height; micro-inches (US customary units), microns (metric units), or N scale (ISO 1302:2002). In U.S. customary units, 1 R a is typically expressed in “millionths” of an inch.