The four forwards join Jonny Arr, Chris Pennell and Josh Drauniniu who have also recently pledged their playing futures to Warriors.
All-action front row Shervington, who has been capped by Wales at Under-21 level, joined Warriors in 2010 from Ospreys. He has become an established member of the senior set-up making 55 appearances in all competitions, scoring four tries.
"Ed has really progressed since he has been at Sixways and proven himself to be a genuine first team hooker in the Aviva Premiership," said Head Coach Richard Hill.
"He works so hard you have to drag him out of the gym as he would be in there all day and all night. He compliments Aleki Lutui with his style of game and is very strong in the set piece so we are excited that he has committed his future to us."
Dynamic flanker Betty, who can operate at both openside or blindside, has been a revelation for Warriors since making the step up from Cornish Pirates in 2011. Betty's first season saw him pick up the Players' Player of the Year Award at the club and the no-nonsense forward has since gone onto make 43 appearances for Warriors.
"Sam has made the transition up from the RFU Championship, which is not an easy thing to do for a forward, and been fantastic for us," said Hill, who regularly deploys Betty as one of the club's defensive captains.
"He is regarded as one of the best defensive back row forwards in the Aviva Premiership and is a hard man who will do anything for this club. He is also developing his attacking game which is very encouraging."
Loosehead prop Porter, who joined Warriors from Plymouth Albion, has also signed new terms to continue his development at Sixways.
"We see George as an athletic and mobile loosehead who suits the fast game we want to play," commented Hill.
"He has a big future in the game and has been unlucky with a shoulder injury this season that has restricted the amount of time we have seen him in action. But we have seen more than enough to convince us that he has a bright future at Warriors."
The club is also delighted to announce that young back row prospect De Carpentier will remain at the club. Former Leicester Tigers player De Carpentier moved to Warriors in October and has now been rewarded for his performances on the training field and in cup action with a contract extension.
"Richard's attitude is excellent. He is really dedicated, hard-working and wants to improve himself all the time," added Hill.
"He has been unfortunate that he has had to bide his time for opportunities, but he made a very impressive display against London Irish at the weekend to show the talent we know he has. He is one of the younger members of the squad and a very exciting English talent for us to work with."