Fundamentals of Hydrotest Requirements and Methodological Approach
Authors: Ameh SE
Nowadays, existing pipelines are being hydrotested to demonstrate fitness for service due to difficulty in inspecting with conventional in-line tools resulting from flow condition, pipeline configuration and lack of pigging facility. Pipeline operators still view hydrotest as a difficult operation because of lack of robust methodological approach and difficulty in meeting hydrotest and dryness acceptance criteria. The present study considers detailed overview of hydrotest procedure, acceptance criteria and critical parameters such as entrapped air, water compressibility and temperature that influence hydrotest result. These parameters have formed the basis for measuring acceptance criteria of hydrotest result. Maximum allowable air volume in pipeline to meet hydrotest acceptance criteria is 0.2 percent while maximum allowable leftover water after dewatering is 4 percent volume of pipeline. But the dryness criteria for sales gas is a minimum of -20 oC dew point. Mobilization of adequately rated and calibrated test equipment and effective implementation of procedure would enhance hydrotest, dewatering and dryness results.
Affiliations: Department of Mechanical Integrity, Chevron Nigeria Limited, Delta State, Nigeria
Keywords: Acceptance Criteria, Hydrotest, Pipeline, Pigs, Test Pressure
Published date: 2018/12/30