4.90 [March.",, 



Ashburner.] *^U 



sands in the counties of Warren, Venango, Clarion and Butler ; of this 

 number 122 were dry hales or produced no oil ; being 25.7 per cent. 



In the Bradford or Northern district, there were during the same year, 

 2536 wells drilled to the Bradford oil sand, of which number but 76 were 

 dry holes or only 3 per cent. ; being nearly 23 per cent, less than iu the 

 Venango or Western district. 



The average daily production, for the first month, of the wells drilled in 

 the Bradford sand was ahout 20 barrels, while for the wells in the Venango 

 sands it did not attain that amount.* When we take these facts into con- 

 sideration, we can readily understand why there should have been 2536 

 wells drilled in the Northern district to only 475 in the Western. 



Since the beginning of the year 1875, when the Bradford oil horizon was 

 discovered, there have been 6249 wells drilled in the district, of which 236 

 were dry holes or 3.77 per cent. From the most authentic statistics which 

 I can gather in the Western district, about one-fourth of all the wells 

 which have been drilled in the Venango sands, since their discovery in 

 1859, have proved dry. 



The Bradford sand consists of a gray and white sand, of about the same 

 coarseness as the ordinary beach sand of the Jersey coast ; compact, yet 

 loosely cemented. The average thickness of the sand is about 45 feet, 

 and from top to bottom, the sandy strata change but little in their general 

 character. It is only when specimens from the successive layers are placed 

 side by side and closely examined, that any difference in structure can be 

 recognized. The grains of sand are angular, vary but slightly in size, 

 color and the quantity of cementing material which holds them together 

 in their rock bed. 



The same homogeneousness, which characterizes the vertical section, is 

 found to exist over a considerable horizontal area. In fact but little change 

 is found to exist in the sand obtained from wells 15 miles apart, or in the 

 sand from the intermediate wells. 



The greatest length of the Bradford district is 18 miles north, 30° east ; 

 its greatest width is 12 miles in a north and south direction. The area of the 

 territoiy is between 100 and 110 square miles. In this area the sand is so 

 regular and constant that if wells were drilled at random the number of dry 

 holes, which would be obtained, would hardly exceed 2 in every 100. The 

 percentage of dry holes spoken of as being obtained in the district includes 

 those which were drilled outside of the probable oil territory and were 

 genuine wild-cat wells. 



In the Western district the characteristics of the Venango sands are quite 

 different. The third or bottom sand, which is the most productive of the 



* Some of 1 1n' wells drilled to the Venango third oil sand have produced from 

 2000 to 8000 barrels of oil per day, while the largest well ever found in the Brad- 

 ford district has not exceeded as many hundred. The largest individual wells 

 have been located in the Western district; the largest average wells in the 

 Northern district. 



