Charles Simmons was the first known inventor to use ball sealers in a well in 1953. Charles was working at Western Company of North America when he went to a dime store in Borger, Texas and bought 40 soft jack balls. He cut open the jack balls and inserted regular marbles inside them. He tested the casing perforations at the Borger district yard to make sure the holes would be plugged by the ball sealers.³ As hydraulic fracturing techniques developed, commercial wells were successfully completed in the mid 1950’s. In early 1956, the oil and gas industry documented the use of perforation ball sealers as being significantly lower in cost than conventional packers.⁴As conventional ball sealers were continually used in the industry, guidelines were added to help optimize perforation sealing efficiency in 1963.⁵ There were three basic types of ball sealers used in the industry, non-buoyant balls (Sinkers), buoyant balls (Floaters), and neutral buoyant balls. For vertical wells the non-buoyant balls usually had 50 to 100% excess of the number of perforations used based on the flow rate. ⁶ In 1992, additional testing was done to determine that in vertical wells non-buoyant balls provided the best efficiency, while neutral buoyant balls were the best in horizontal wells.⁷ In the late 1970’s ball injectors (Ball Guns) were used to pressurize the stream directly into the well during completion. Ball injectors can reach pressures up to 15,000 psi [103 MPa] using a manual hand crank or a remote controlled motor. The conventional ball sealers are available in different densities and materials such as rubber, nylon, or phenolic with the most common sealing ball surface being rubber-coated nylon (RCN). The most popular size ball sealers are 7/8 inch [22.2 mm] but other sizes are used from 5/8 inch [15.9 mm] to 1 ¼ inch [31.8 mm]. Conventional ball sealers have limitations in many perforated well completions. Non-buoyant balls can be difficult to drill out plugs and retrieve tools below perforations. Buoyant and neutral buoyant balls require a ball catcher to make sure any chokes, production equipment, or restrictions are recovered. All conventional ball sealers also can be stuck on the perforations in low pressure reservoirs and may require a wiper run to knock off the balls.In 1998 water-soluble ball sealers were first invented using collagen to address the conventional ball sealers’ issues stated above. The collagen balls only had a reservoir temperature range of 100°F [38°C] to 200°F [93°C].⁸ Eventually complex copolymer plastic water-soluble ball sealers were replaced to provide a range of 75°F [24°C] to 300°F [149°C] reservoir temperature. The mechanical integrity can be up to 4000 psi [27.6 MPa] after 1 hour of exposure at 230°F [110°C] (PS-HT). Perforation ball sealers have been in the industry for over 60 years. Ball sealers are still a staple used today in acidizing and hydraulic fracturing completions for mechanical fluid diversion and to reduce near wellbore damage. It is impossible to monitor the amount of ball sealers used in the oil and gas industry, although it is expected that all fields in the world have benefited economically in increasing production of oil and gas from ball sealers.