728 



Subsurface Geologic Methods 



During this period the well had a peak production of approximately 

 70 BOPD, whereas the production immediately before the Hydrafrac 

 treatment was averaging 40 BOPD. After about the 17th day of produc- 

 tion following treatment, this well had settled down to a 63 BOPD aver- 

 age; thus an increase of 23 BOPD resulted from the Hydrafrac treatment. 



Well C in figure 389, also a Springer sand well in the Sholem-Alec- 

 hem field of Oklahoma, shows an entirely different type of pressure break 

 during the course of the Hydrafrac treatment. In this case the sharp break 



WELL C 



SHOLEM ALECHEM FIELD.OKLA. 



BEFORE DAYS AFTER 



Figure 389. Pressure and volume of injection changes during Hydrafrac treatment. 



of pressure probably occurred at the initial fracture. The declining curve 

 indicates a rather typical extension of the fracture. Treatment in this 

 case was through perforations of 5286 to 5310 feet. The production curve 

 after treatment shows a flush production peak of about 75 BOPD, with a 

 decline for a few days and a net increase of 26 BOPD resulting after the 

 treatment. In this particular instance the 47 BOPD was the result of vol- 

 untarily lowering the production of the well to meet the allowable rate 



