Fracking, or hydraulically fracturing, involves extracting gas from rocks by breaking them up with water and chemicals at high pressure.
Operations at the first well at the Preston New road site in Lancashire where halted several times last year because of minor seismic events. British regulations demand work be suspended if seismic activity of magnitude 0.5 or more is detected.
Cuadrilla CEO Francis Egan said he hoped the use of a thicker fracking liquid would help to cut down on seismic events at the second well.
"We have in effect increased the concentration of the fluid so essentially there is more sand and less water," he said in an interview with Reuters.
"We may still have events reaching the 0.5 limit but hopefully not as many."
Egan said the fluid alterations had been approved by Britain's Environment Agency.
Cuadrilla and chemical firm Ineos, which has the largest shale gas licence acreage in Britain, have called on the government to change seismicity regulations which the companies say have threatened to stall the industry's development.
The government has said it has no plans to change the rules.
Fracking is opposed by environmentalists who say extracting more fossil fuel is at odds with Britain's commitment to reduce greenhouse gas emissions.
"At a time when the government has declared a climate emergency, the last thing we should be doing is starting an industry that extracts gas," said Jamie Peters, a Friends of the Earth campaigner.
Britain last month became the first G7 country to adopt an ambitious law to reach net zero emissions by 2050.
The move will require much less gas-fired power generation and a move away from domestic natural gas, currently used to heat around 80% of the country’s homes.
But Egan said the fracked gas could become a feedstock to create hydrogen and help the country meet its climate target.
"The CCC (committee on climate change) report was clear hydrogen will be needed for net zero and surely it’s better to use domestically produced gas for this than imports of LNG (liquefied natural gas)," he said.
Britain’s climate advisers, the CCC, said in a May report Britain will need to begin using low-carbon hydrogen in industry and for home heating to help cut its emissions and meet the target.
Subject to regulatory approvals Cuadrilla said it would complete the programme of fracking and testing equipment at the second well by the end of November.
(Reporting By Susanna Twidale in London and Lefteris Karagiannopoulos in Oslo, Editing by Edmund Blair and Jane Merriman)
By Susanna Twidale and Lefteris Karagiannopoulos