(Adds statements from Phillips 66 and Enterprise Products Partners, context and background on earthquakes)
HOUSTON, July 14 (Reuters) - An earthquake with a preliminary magnitude of 4.2 on Friday struck Stroud, Oklahoma, about 20 miles (32.2 km) from the key oil storage hub in Cushing, Oklahoma, the Oklahoma Geological Survey (OGS) said.
There have been no initial reports of damage from the quake, Oklahoma Corporation Commission spokesman Matt Skinner said by phone, cautioning that it was still early to determine the impact of the temblor.
A series of aftershocks shook the area in the hour following the earthquake, including two quakes measuring at magnitude 3.7 and 3.8, according to the U.S. Geological Survey.
So far, oil companies operating the tanks and pipelines around the Cushing hub have reported no damage. Phillips 66 said it was monitoring the situation but was not impacted. Enterprise Products Partners said it had assessed its facilities and found no earthquake-related issues.
Oklahoma has experienced a rash of earthquakes in the past few years following a surge of oil and gas production in the state. The quakes have been attributed to the injection of saltwater, a normal byproduct of oil and gas production, into disposal wells.
Several larger quakes have occurred previously near the Cushing storage hub, which is the delivery hub for U.S. crude oil futures and houses some 57.6 million barrels of oil. It is sometimes referred to as the "Pipeline Crossroads of the World."
In November 2016, a magnitude 5.0 earthquake impacted residents and businesses about two miles (3.2 km) west of Cushing. (Reporting by Liz Hampton in Houston; Editing by Chizu Nomiyama and Marguerita Choy)