The ability of oil companies to squeeze out more production from mature fields by using new technology has also added to the surplus.

But first he paused to gather some straw from a mature field and fashioned it into a crude saddle.

It is a mature field in decline, and is run entirely by small independent operators.

These should more than compensate for the natural decline in other more mature fields.

But it is a mature, crowded field, and one that is going digital slower than expected.

It was a mature magazine fighting for market share in a mature field.

Larger oil companies have steeper production-decline rates because they own older and more mature fields.

As is often true with mature fields, though, the big companies that developed them have started to move on.

Now they are putting back the more mature field that we were playing on in the preseason.

Natural language understanding is not a mature field.