Hovea 8 well — casing corrosion
4833. Hon Alison Xamon to the Minister for Mines and Petroleum
I refer to the casing corrosion in the Hovea-8 well, and I ask —
(1) How old was the casing around this well?
(2) Is this level of corrosion common in casings of this age?
(3) Was this well and casing correctly constructed in accordance with best practice?
(4) Had this well and casing been subject to any of the stresses that accompany the practice of fracking?
(5) Had acid been pumped down this well?
(6) Had this well and casing been subject to high-pressure similar to those used in hydraulic fracturing?
(7) What, if any, differences in well and casing construction are required for wells that will be subject to fracking?
Hon NORMAN MOORE replied:
(1) Construction of the Hovea 8 well was completed on 13 August 2003.
(2) No. Corrosion is a managed risk at any oil and gas production facility. Tubing replacement and workovers are widely utilised as a remedy for corrosion. Well work-overs are covered under clause 630 of the Schedule of Onshore Petroleum Exploration and Production Requirements 1991.
Well tubing is the first line of defence for protecting casing. Corrosion of casing occurs from time to time, however there are well established methods to directly patch and repair casing.
(3) Yes.
(4) No.
(5) Yes, this well has previously been treated with an acetic acid, to remove carbonate scale that inhibits production.
(6) No.
(7) Wells that are subject to hydraulic fracture stimulation may require higher pressure rated well casing and casing cement specifications, along with more stringent monitoring and testing of the casing cement.