I am very worried as I have 15+ backlogs..if I get ielts 6.5 bands then..will my visa be approved?

 So I won't be sugar coating anything. I will be completely blunt and straightforward with you. See, IELTS and backlogs are two independent things. Having a score of 6.5 in IELTS will have a neutral effect on your VISA. Listen, for approval of a visa, the authorities check the student's overall profile, both in academics and other fields, including your extracurriculars, work experience, and other endeavours. 

So, your backlogs will have a very negative impact on your visa process. I am sorry, buddy, I did not want to hurt your feelings, but this is true. Suppose a person is going for a study permit. In that case, he must also have amazing academic scores and good participation in other fields because the authorities are more interested in knowing what the student can contribute to the economy and their existing student crowd. IELTS is proof of your English proficiency, nothing else, so it will not impact the visa application. But, if you can get a score of around 7.5 - 8 in your IELTS, the chances of approval might get slightly higher. 

Don't get disheartened, champ. I know you can accomplish all your goals and fulfil your dreams. I am just a click away if you need any other assistance.