The wells that Edwin Drake drilled, were actually mostly dusters , loaded with salt water. A russian surveyor, in the mid 1700s had come to PA to see about larger tracts of land with good lumber resources. He came up to the (present) counties of Warren and VEnango (At that time Connecticut was a major claimant of PA lands. The Russian had the presence of mind to actually map all the oil seeps he came alcroos in these counties and discovered that they created a pattern on a map (most geology is originally just dumb luck). The "Oil SPrings" were then exploited for the natural seepage for about 100 years until the Seneca Oil partners (Which included Drake) saw a German process for making kwerosene out of paraffin based oils. SO Drake, a retired railroader, had a map sense to know the Oil Creek locale and he had a sense of how to get below the large cobbles and sands that seemed to be a source rock for these petroleum seeps. He started with a steam drill which promptly burned to the ground (DUHH, oil and wood fired steam engines are not friendly associates).
DRake brought in his first well as you say and what hes most remembered for is not drilling techniques (The Chinese discovered the drill bit) but bringing on some techy help to enhance the production of oil wells that quickly began to decline in yield after but a month ortwo. The wells were relativelt shallow<75 feet after several drill campaigns The first oil was produced at about 30 feet (called the famous "30 foot sand") There are bars in Erie and VEnango County with names celebrating the 30 ft sands (other famous drill sands [and bars]are The Oswayo,Venango First, Rosenberry, Salamanca, Gray, Knox, SHira, Wolf Creek, Clarion, Big Tuna, etc etc).
All these wells would produce like crazy for a couple weeks and then just sputter. The technique of recovery and control was not known at first . SO a state geologist ,John CAril ,was hauled up to Venango by Drake
"ATSA MATTA MY WELLS?" Drake asked Caril
Caril studied and studied and, one day, after a serious series of sudden Summer Squalls, he noted that, whenever wells were allowed tofill with water, the wells nearest beside them would accumulate oil and start increasing their yields of petroleum by geometric and often logarithmic amounts.
So,the science of waterflooding was born and was the savior of the entire VEnango and Pa oil industry. Today, many of these earliest wells have been deepened and allowed to be enhanced by chemical[secondary] recovery tricks (They flood the wells with detergents which makes the oil soluble and easier to pump out, or they steam heat the formation to drive out low end "crack" products)
Drake also started the trick of sealing off leak zones so that wells didnt fill up with salt water. Drake Actually did discover WELL CASING. (another duuh moment , when Drakes wells would fill up with water halfway through drilling he ordered some pipes to pump the water out. One of the drillers , so the story goes, decided to ram the bit down through the pipes and then got it stuck. SO they brought in a steam donkey engine to drive out the pipe and found that, besides separating the pipes , they could seal off the water leakage zone by pounding the casing into the hole.
Nothing in this world, including drilling for oil, just happens at the outset as designed. Drakewas going to use cable drilling only to "push and pulverize" the glacial cobbles in the hole and instead discovered that a driven or drilled well was the best way to collect the surface and shallow oil. Then , as he went deeper, the casing discovery came in handy. Finally, when the wells ran out of oil (because the oil recovery is really close by the well bore ) waterflooding was used to "drive" oil from the surrounding formation towards the oil well itself.
Drake was a good planner and was able to get others to help him solve problems. Besides, he was kinda lucky to have had the maps that the Russians had spent time in compiling and decided to drill where all the biggest oil seeps were already known to exist.
Now, the earliest oils has been reported by FRancis Drake who used oil from a spring lake to make reed torches. Indians knew of oil, as did many settlwers, who used the pewtroleum as medicines and as lamp fuel and pitch for sealing their log cam[noes and pirogues. Tree sap was most desired for caulking but oil ws more plentiful.