Chinese developed drilling techniques for oil a long time ago
Summary
- Around 200 BCE, Chinese of hte Han dynasty were using percussion drilling to drill oil.
Details
- The method was used to extract natural gas to burn brine and produce salt.
- It used iron bits, iron pole and levers.
- The bits were repeated raised and dropped and was quite effective - by the 10th century percussion wells deeper than 100m were common, and the deepest was in 1835 of 1km below the surface (though the deeper wells might take generations to sink)