# Assessing Methane Emissions from Shale Gas Production in China: A Two-Tiered Mobile Measurement Approach

## TL;DR

This study measures methane emissions from shale gas production in China using a mobile approach, finding that a small fraction of well pads produce most emissions.

## Contribution

A novel two-tiered mobile measurement approach is introduced to assess methane emissions from China’s shale gas production.

## Key findings

- 89% of methane emissions came from just 10% of the well pads.
- Estimated methane emissions in 2023 were 16,842 t with a leakage rate of 0.10%.
- Gas lift venting and compressor combustion were identified as major emission sources.

## Abstract

China, holding the world’s largest shale gas reserves,
lacks
precise data on methane emissions from its rapidly expanding production.
We introduce a two-tiered mobile measurement approach, using a mobile
laboratory to measure methane concentrations across 125 well pads
(approximately 750 wells) distributed among four major production
blocks (Changning, Weiyuan, Fuling, and Luzhou). These blocks contributed
84% of China’s total shale gas production in 2023, providing
the first comprehensive ground-level measurements. Stationary downwind
monitoring of well pads revealed emission rates from 0.002 to 98.86
kg/h, validated through mobile observations of methane concentrations
across the region. Notably, emissions were highly concentrated, with
89% originating from just 10% of the well pads. For 2023, the extrapolated
methane emissions from China’s shale gas production were estimated
at 16,842 t (6,444–29,991 t, 95% CI), corresponding to a
methane leakage rate of 0.10% (0.04%–0.17%, 95% CI). This rate
is lower than major U.S. fields and similar to that of U.S. dry gas
fields. Our research identifies gas lift venting, incomplete combustion
from compressors, and process venting as significant sources of super-emissions
in China’s shale gas upstream production chain. The methodology
employed, based on comprehensive and targeted field measurements,
demonstrates its effectiveness in providing a scientific basis for
formulating precise and effective regulatory policies on methane emissions.