CNPC Uses an Iterative Two-Stage Convex Relaxation Approach to Operate Natural Gas Pipelines

AbstractChina National Petroleum Corporation CNPC, the largest oil and natural gas producer and supplier in China, plans annual and monthly natural gas production quantities, consumption levels, and transmission amounts. We developed an iterative two-stage convex relaxation approach to solve this challenging task. In the first stage, we estimated the physical parameters for pipelines according to a given set of gas flows and gas pressures. In the second stage, we used these parameters to solve for a new set of gas flows and gas pressures. Through numerical tests with the current pipeline network, the proposed solution approach can converge within a two percent relative error within five minutes. The solution approach is expected to generate an extra 2.1 billion Chinese yuan CNY for CNPC's natural gas usage between 2016 and 2020.