Generally the standard is abuse of discretion, unless the discovery issue concerns Constitutional issues (e.g., right to privacy) or concerns the interpretation of a section of the discovery act, in which case the standard is de novo.
The fact that the writ petition does not specify the standard of review is itself a sign that the petition is doomed to fail.
Best of luck.
Nothing contained in this communication is intended to be, or shall be deemed as, legal advice, counsel, or services to on or behalf of any person or any entity. Usage of the Avvo website is not intended to and shall not create any obligation or relationship between the user and the Law Office of Herb Fox, including but not limited to, an attorney-client relationship. Further, the communications on this website between you and the Law Office of Herb Fox may not be privileged or confidential. Finally, your situation may be governed by deadlines that may or may not have already lapsed, and you may lose your rights if you do or did not act within those deadlines.
The basis for the Writ - i.e. what mistake or error of law is the appellant contending - dictates the standard of review. You are probably right. It will likely be abuse of discretion. However, at this point, it is not your burden and should not be of any concern to you. It is entirely within the discretion of the appellate court whether to grant immediate review by writ petition of the challenged order. The great majority of such writ petitions are summarily denied. If the court agrees to review the order (which is unlikely), the appellant then must file his or her opening brief in which he/she will likely include statements/discussion regarding which standard of review applies. If it actually gets to the point where an opening brief is filed and you want to respond, I would highly recommend you hire an appellate attorney to prepare the brief for you and appear for the oral argument, if any.