"Foreword: a. This recommended practice is under the jurisdiction of the API Committee on Standardization of Drilling Fluid Materials. b. The purpose of this recommended practice is to provide standard procedures for the testing of liquid drilling fluids. It is not a detailed manual on mud control procedures. It should be remembered that the agitation history and temperature of testing have a profound effect on mud properties. c. This recommended practice is organized to follow the tests as listed on the API Drilling Mud Report form (API RP 13G@ Second Edition@ May 1982). Additional tests are given in the Appendix of this recommended practice. d. Metric ""SI"" unit equivalents have been included in this publication in parentheses following the U.S. customary units. e. Additional publications under jurisdiction of this committee: Spec 13A@ Specification for Oil-Well Drilling. Fluids Materials@ covers specifications and test procedures for barite@ weight material@ bentonite@ non-treated bentonite@ attapulgite@ sepiolite@ starch and technical-grade low viscosity CMC. Bul. 13C@ Bulletin on Drilling Fluids Processing Equipment; Bull@ 13D@ Bulletin on the Rheology of Oil- Well Drilling Fluids: RE 13E@ Recommended Practice for Shale Shaker Screen Cloth Designation: RP 13G@ Recommended Practice for Drilling Mud Report Form: RP 131@ Recommended Practice for Laboratory Testing Drilling Fluids; RP 13H@ Recommended Practice .for Drilling Fluid Bioassays; RP 135@ Recommended Practice for Testing Heavy Brines: RP 13K@ Recommended Practice for Chemical Analysis of Barite."