API 7CW 2020 pdf free download
API 7CW 2020 pdf free 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. 3.1.14 manufacturer Principal agent in the design, fabrication, and furnishing of the test specimen who chooses to comply with this standard.
4 Testing 4.1 General While a surface finish of a solid may appear to be very smooth, microscopically small topographical irregularities cover the solid surface. These irregularities are called asperities. Surface roughness is a general geometric characteristic of asperities on a larger scale. A common measure of average surface roughness, R a , is expressed in units of height. In U.S. customary units, 1 R a is typically expressed in “millionths” of an inch or micro-inch. As two solid surfaces meet and frictionally interface with one another, wear mechanisms such as galling, grinding, machining, or polishing may create wear debris of various shapes and sizes. The rate of material removed per unit of time or distance creates a dimensional change described as a wear rate. The term coefficient of friction describes the dimensionless ratio of the friction force between two bodies to the normal force pressing these bodies together. Axial friction factor is a related term that describes the ratio of frictional force and contact force between the test specimen and the casing while sliding (not rotating). Rotational friction factor describes the ratio of frictional force and contact force between the test specimen and the casing while rotating. Three-body abrasive wear is a common occurrence when loose particles are introduced or generated between two contact surfaces. Critical wear groove depth is demonstrated in cases of severe wear, where the entire tool joint specimen diameter may protrude through the casing wall.
