one of the most recent approaches to plug and abandon wells and patch casing leaks entails an alloy that flows like water.
a metallic alloy that has water-like viscosity in its molten country after which rapidly solidifies right into a gas-tight seal lately accomplished its three hundredth downhole deployment. that is consistent with a brand new announcement from uk-primarily based bisn oil tools which develops bismuth plugs for a number of applications.
founded in 2011 and subsidized via bp’s challenge capital unit, bisn stated oil and gasoline organizations around the sector had been using its innovation in locations where they could otherwise use cement or elastomers. set up use cases for onshore and offshore wells consist of permanent properly abandonment, casing/tubing repair, and to close off water- or sand- production zones.
bisn’s generation hinges on a customizable alloy made often of bismuth and tin, whose respective elemental abbreviations of bi and sn form the enterprise’s call.
the company’s proprietary alloy is sent downhole in its stable nation as a solid around the outdoor of a heating system. the warmth element is made of thermite—a compound of iron oxide and aluminum powder—that desires most effective a small burst of strength introduced through an electric line to trigger a chemical response.
as soon as the warmth rises to a predetermined melting factor, the bismuth-based totally alloy begins to go with the flow. bisn stated the liquid alloy will cross everywhere in and around the properly that water can waft. this includes perforations, screens, and the annulus.
bisn defined the solidification system as “almost instantaneous” as the alloy shifts from a liquid to a solid as soon as its temperature falls underneath the melting point. throughout this transition, the alloy expands similarly to how water does while it cools into ice.
all of this takes just a few mins, and inside a few hours, the properly is ready for a strain take a look at to peer if the seal holds.
bisn stated it controls the melting factor and the heat of its thermite gadget using damping and binding chemicals. this prevents the exothermic reaction from growing temperatures that might harm the nicely’s casing or its completions components. the upper restriction bisn makes use of for its plugs is about three hundred°c (572°f), while casing can start to degrade from immoderate heat at
plugging a billion-barrel area
the largest abandonment activity bisn has undertaken to this point changed into the focus of a case have a look at supplied at this 12 months’s offshore era conference (otc) in houston. in otc 31897, authors from bisn and akerbp shared information on how 35 bismuth plugs have been used to plug and abandon (p&a) 30 wells offshore southern norway.
the p&a marketing campaign became achieved on the valhall oil field which turned into found in 1975 and has produced greater than 1 billion boe over the last 40 years. akerbp wants to produce any other billion boe from the sphere over the next forty years. to do that, it needed to plug all of the original wells so it is able to drill new ones.
a highlight of the p&a project consists of using the largest bismuth plug ever made. that is in keeping with bisn and akerbp which referred to within the paper that the document-placing plug measured 50 ft long and weighed almost 34,000 lb, about 20,000 lb of which comprised the bismuth alloy.
over the direction of the 30-well challenge, bisn and akerbp reported that 350 tons of bismuth alloy changed into despatched downhole. the generation changed into credited with assisting akerbp trim its authentic p&a timeline from 10 years of operational time right down to four years.
this accompanied the primary p&a marketing campaign performed in 2014 that used conventional sealing technology. after that first attempt to seal the wellbores off, 14 showed no sign of annular gasoline strain. however, the situation grew more concerning over the years.
by way of 2019, the number of wells with zero stress buildup shrank to simply four.
it changed into round that point that akerbp sought to qualify the bisn technology with a 2-yr test internal a nicely with one of the maximum levels of sustained casing pressure.
downhole gauges confirmed that the top segment of the annulus in which the primary bismuth plug become used had a zero psi analyzing at some stage in the two-year monitoring attempt. downhole cameras have been extensively utilized and provided visual affirmation that no gasoline bubbles have been flowing beyond the plug vicinity.
due to its noncorrosive nature, bisn mentioned that the alloy plugs must preserve for many hundreds of years. this is primarily based on laboratory effects cited in the agencies’ technical paper which endorse the life of the plugs may even exceed one hundred,000 years.
for further analyzing
otc 31897 bismuth plugs used to cap all wells in the course of the final section of the valhall dp abandonment marketing campaign, offshore norway by egil thorstensen, kjetil vadset, martin knut straume, and laurent delabroy, akerbp; gasser abdelal, queen’suniversity, belfast; paul carragher, jeff fulks, and david leslie mason, bisn oil gear ltd.