Quick Plugging of Shut-In Wells at Valhall
Through utilisation of the PWC (Perforate, Wash & Cement) plug and abandonment method (P&A) on the Valhall field, HydraWell has contributed towards Aker BP executing its plugging programme significantly quicker than planned. Since May 2017, HydraWell has contributed towards plugging 10 shut-in wells on the original drilling platform (DP) at the Valhall field centre.
Compared to the first P&A phase on the DP platform from 2014 to 2016, Aker BP has reduced the average time per well by 50% in the latest phase, despite a rise in the complexity of the wells towards the end of the campaign. Plugging wells on the DP platform is a key part of the work to modernise the Valhall field centre. The three original platforms from when the field started producing in 1982 – QP, DP and PCP – will be removed. Four wells remain to be permanently plugged prior to the removal of the DP platform.
“We have significantly reduced the execution time of our P&A operations through improving a number of elements. HydraWell’s PWC technology, with HydraHemera in front, is one such element. Among other things, we have run computer simulations to identify how much time we need to wash the back of the casing before the cementing starts. This has improved our understanding and means that we can do things faster than before,” says Martin Straume, Drilling Engineering Manager P&A of Aker BP. “In addition, together with HydraWell we have started running one-trip systems on applicable wells. This means that we drop the perforation gun into the well instead of pulling it back up before we start washing. This has contributed towards reducing execution time significantly,” Mr Straume adds.
HydraWell’s HydraHemera PWC system perforates the well before washing the casing and then setting the cement plug – a so-called rock-to-rock barrier that is required under the Norsok standard. Through this method a rock-to-rock barrier can be installed in less than two days. The technology can be utilised on both single and dual casing wells. “It is impressive to witness how Aker BP leaves no stone unturned to identify improvements with regards to execution time, HSE and costs. We are proud to contribute with technology and knowledge towards this work. PWC reduces both costs, HSE risks and the environmental footprint of each plugging operation, so we feel that we are a good match for Aker BP’s ambitions,” says Arne G. Larsen, HydraWell’s Vice President of Business Development.