MSSQL Audits are growing out of control. 1gb every 4 minutes - any way to get size down?
Auditing should be enabled based on requirement from Compliance/IT security or Audit department of your organization. If you enable auditing as mentioned in this link, it would start auditing each and every thing. It will not only make audit files to grow rather, it would impact on performance of your instance badly.

Ideally if you follow C2 auditing, it captures basics of auditing and is accepted internationally.


  C2 Auditing and Common Criteria Compliance are two internationally
  accepted auditing standards.
  
  C2 audit mode is the auditing option that can be used to facilitate
  auditing standard. By enabling C2 auditing, it allows the
  administrator to enable a comprehensive type of auditing, logging.
  This is named as C2 audit mode because it is logging of the form
  specified by the U.S. Department of Defense regulations to meet the
  certification at the C2 level of trust. Those regulations were
  specified in a document called the Trusted Computer System Evaluation
  Criteria, often referred to as the “Orange Book” in the “Rainbow
  Series.” The Orange Book is now depreciated in favor of the Common
  Criteria. Nonetheless, C2 Auditing is still a commonly used term.
  
  C2 audit mode generally means assigning a unique generated audit ID to
  each group of related processes, starting at login. Thereafter,
  certain forms of system calls performed by every process are logged
  with the audit ID.


You might read more about C2 auditing at this link.

There is another method of auditing accepted called "Common Criteria Compliance" and details are as below:


  C2 auditing has been deprecated by the Common Criteria specification
  which was developed by the European Union. Common Criteria Compliance
  is internationally recognized set of guidelines for security for
  information technology products. This is applied to operating systems,
  Databases, Network Devices and Smart cards etc. Common criteria
  certified products have been rigorously evaluated by accredited third
  party security labs.
  
  This option is available same versions as C2 Audit but Common Criteria
  Compliance is available in Enterprise and Data Center editions of SQL
  Server 2008 R2 and after versions. However, with respect to the SQL
  Server, if you are complying with either C2 or common criteria, the
  audit result is similar. In the case of Common Criteria Compliance,
  audited data can be viewed from system views which is more secure than
  the C2 audit mode.


if you enable one of them, your problem of file size and performance should go.

In case, you are really interested to get to the root of your culprit in your current scenario then, you should query your audit log and group them by action and disable that event, same can be done using below query:

SELECT action_id, count(*)
  FROM fn_get_audit_file( 'E:\Test\Audit-*.sqlaudit' , DEFAULT , DEFAULT)
group by action_id 


Please remove SCHEMA_OBJECT_ACCESS_GROUP from auditing events and you should be fine for disabling select statement from audit. You can check more about this at link.

Hope this helps.