The number of holes made to probe the dimensions of oil and gas fields greatly exceeds the number of holes made to get oil out .. and the number of holes drille

The number of holes made to probe the dimensions of oil and gas fields greatly exceeds the number of holes made to get oil out .. and the number of holes drilled to estimate mineral reserves (copper, gold, kimberlite (diamonds), bauxite, etc. etc. etc) is large in comparision to oil wells. The point of all those holes is to log layers, horizons, sediments, etc and to map out the geology of very large areas .. much much much larger than the combined bore hole diameter areas. Of course boreholes are the final step in "proofing" siesmic results that map out many layers across large areas and allow geologists to rule out many areas as not having the structures required to trap gases.