A CRJ FLIGHT CREW EXPERIENCED ENGINE OIL WARNING AFTER TAKEOFF. THEY MONITORED THE INDICATIONS; COORDINATED WITH MAINTENANCE; AND DECIDED TO RETURN TO THEIR DEPARTURE AIRPORT.

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WE DEPARTED ZZZ. DURING THE TKOF ROLL; I NOTICED THE R ENG OIL PRESSURE FLUCTUATING. AFTER AN INITIAL ANALYSIS THAT THE AVERAGE VALUE WAS BELOW THE MINIMUM 45 PSI FOR TKOF I CHKED THE AIRSPD AND WE WERE WELL OVER 100 KTS. I DECIDED TO CONTINUE AND WATCH THE ENG IN THE CLB RATHER THAN CONDUCT A HIGH SPD ABORT. AT ABOUT 1200 FT AGL WE GOT AN ENG OIL WARNING. A QUICK SCAN OF THE ENG INSTS SHOWED THE SAME VARIATION IN OIL PRESSURE THAT I HAD SEEN ON THE TKOF ROLL. OIL TEMP; HOWEVER; WAS NOT INCREASING AND; IN FACT; WAS LOWER THAN THE OTHER GOOD ENG (97 DEGS CELSIUS VERSUS 120 DEGS CELSIUS). ALL OTHER ENG PARAMETERS SEEMED NORMAL. I DID NOTHING UNTIL WE GOT THE FLAPS UP AND GOT ESTABLISHED ON THE DEP (ABOUT 30 SECONDS LATER). THE WX WAS GOOD VMC WITH ABOUT 50 MI VISIBILITY AND ONLY A FEW SCATTERED THIN STRATUS CLOUDS. I HAD AN IOE FO BUT ONE WHO HAD DEMONSTRATED COMPETENCY IN THE CRJ THE PREVIOUS DAY SO I CONTINUED TO LET HIM FLY THE ACFT WHILE I RAN THE QRH CHKLIST. ABOUT THIS TIME THE MESSAGE EXTINGUISHED ONLY TO COME BACK ON ABOUT 60 SECONDS LATER. I RAN THE QRH CHKLIST FOR A LOW ENG OIL PRESSURE MESSAGE. THE QRH CHKLIST FLOW LED ME TO REDUCE PWR ON THAT ENG AND INSPECT THE OIL PRESSURE FOR A DROP BELOW 25 PSI. IN FACT; THE OIL PRESSURE DID THE OPPOSITE -- IT ROSE TO 47 PSI AND AGAIN THE MESSAGE EXTINGUISHED. ALL OTHER ENG PARAMETERS LOOKED NORMAL SO WE SLOWLY INCREASED PWR ON THE ENG. AT ABOUT 10% BELOW CLB PWR WE GOT THE MESSAGE AGAIN. WE REDUCED PWR SLIGHTLY AND REFERRED AGAIN TO THE CHKLIST. NONE OF THE ENG INDICATIONS MATCHED THE CONDITIONS TO SHUT DOWN THE ENG SO WE RAN THE ENG AT REDUCED PWR IN THE CLB. THE OIL PRESSURE MESSAGES EXTINGUISHED AND REMAINED EXTINGUISHED FOR ABOUT 3 MORE MINS. THE QRH CHKLIST INSTRUCTED US TO OPERATE THE ENG AT REDUCED PWR AND MONITOR THE INDICATIONS. BY THIS TIME I HAD CALLED MAINT AND WAS DISCUSSING THE ISSUE WITH THEM. AFTER A FEW MINUTES DURING WHICH THE MESSAGE WOULD INTERMITTENTLY REAPPEAR; MAINT INSTRUCTED US TO RETURN TO ZZZ. I NOTIFIED OUR DISPATCHER; THE FLT ATTENDANT; AND THE FO. I MADE AN ANNOUNCEMENT TO THE PAX AS TO THE PROB AND THE REASON FOR RETURNING TO ZZZ -- ASSURING THEM THAT THERE WAS NO DANGER. AT THIS POINT WE WERE ABOUT 25 MI W OF ZZZ WITH THE ARPT IN SIGHT. WE NOTIFIED ATC OF OUR INTENTION TO RETURN AND SINCE THE ENG AT THIS TIME SEEMED TO BE RUNNING FINE; I DID NOT DECLARE AN EMER. THE FO AND I BRIEFED THE APCH AND ACCEPTED VECTORS BACK FOR THE VISUAL. OTHER THAN THE MESSAGES INTERMITTENTLY REAPPEARING DURING THE APCH; THE REST OF THE FLT WAS WITHOUT INCIDENT. I CHKED WITH THE FLT ATTENDANT AND THE FO AT THE GATE AND BOTH INDICATED THEY WERE OK TO CONTINUE TO ZZZ1. WE SWAPPED ACFT AND COMPLETED THE FLT.