What makes SeaCure cementing unique?
SeaCure® brings all of the advantages of “Stabbed-In” inner string cementing (which has been standard for onshore, platform and jack-up operations for years) to the subsea offshore environment including better quality cement jobs and improved operational efficiency, as well as mitigating many other types of operational risk.
What is “stabbed-in” inner string cementing?
Our patented SeaCure® system provides a method to physically attach and hydraulically seal the inner string to the float shoe which, after the cement job has been completed, allows the inner string to be safely disconnected and retrieved eliminating the traditional shoe track. Eliminating the shoe track makes drilling out for the next section much easier compared to conventional “poor boy” inner string or subsurface release (SSR) plug cementing systems. Oh, and it saves a tonne of rig time.
What are SeaCure’s® advantages compared to subsurface release (SSR) plug cement jobs?
No plugs! Difficulty drilling out cement plugs and not getting a plug to “bump” are some of the most common issues that can occur in an SSR plug job. Either scenario is likely to be very costly in terms of rig time. Additionally, because of the minimal displacement volume provided through the inner string, SeaCure® jobs can be much more cement efficient. For conductor and surface casing jobs, the operator can pump until return cement is observed at the seabed, utilising additional barrels during losses or saving “excess excess” and creating an oversized patio of return cement around the wellhead.
What are SeaCure’s® advantages compared to “poor boy” inner string cement jobs?
Right from installing the inner string at the rig floor benefit is recognised, taking away the traditional requirement of screwing the first stand of landing string into the top drive to flush the air gap and closing the running tool ball valve in the moonpool. Instead, with SeaCure the inner string seals into the shoe before the running tool is made up, meaning top filling the air gap can be safely done at the rotary table, also providing a hydrostatic pressure test of the inner and casing strings. Because the inner string is stabbed in, the sometimes irregular-topped shoe track is eliminated altogether which makes drilling out for the subsequent section much easier, faster and more reliable. SeaCure® also provides an improved interface between the leading and tailing displacement fluids, ensuring minimal contamination and a better quality cement job compared to the conventional “poor boy” inner string setup. Less contamination means less risk of a slushy/wet shoe and all the associated costly problems. On riserless jobs, SeaCure’s® patented system can facilitate in-situ casing pressure test against green cement to mitigate against the risk of micro-annuli formation.
How much rig time can SeaCure® save my operations?
In general, by eliminating the shoe track, SeaCure® saves a considerable number of hours on the drill out for the subsequent section depending on the particulars of the conventional shoe track design. The fastest drill out we have observed after a SeaCure® job was only 6 minutes. Troublesome drill outs on spinning plugs or large shoe tracks can take many hours, especially if a bit trip or dedicated clean out run is required. If you’re planning a dedicated clean out run, SeaCure® can safely eliminate it and provide straight cost savings to your bottom line.
Can SeaCure® be utilised for liner cement jobs?
You bet. SeaCure® is compatible with all of the major liner hanger assemblies. SeaCure® has some distinct advantages for liner jobs. The inner string reduces the pre-cement displacement volume and helps prevent super-charging the formation prior to pumping the cement job which can damage the formation and potentially lead to well control issues in adjacent wells. The inner string also eliminates the possibility for a cement sheath to build up on the liner ID, which is common on SSR jobs and can inhibit a subsequent cement bond log.
How can you verify the SeaCure® assembly is latched in?
After the SeaCure® assembly is run down to the shoe, the SeaCure® weight set sub applies the necessary force to latch-in, which can be verified with an overpull. The Davis-Lynch latch-in adapter and mating casing shoe design has been successfully utilised around the globe for years. When topping up the casing ID at the rig floor (another unique time saver), the hydrostatic head created by filling the air gap between the sea and rig floor applies typically around 50 psi to the latch-in adapter’s seal assembly as a secondary check.
After the cement job, what’s the difference between utilising Dart versus Ball mechanisms for closing off the inner string prior to pressure up and rupturing the burst disc to circulate out the inner string contents?
Both dart and ball systems are reliable and serve the same purpose. Some of our clients prefer one type over the other. Darts are more typically used in cementing equipment and provide a tertiary mechanical barrier at the shoe which remains in place after the inner string is removed. The tradeoff is that a cement head assembly needs to be rigged up to launch the dart. The ball drop only requires a small, easy to handle 1502 WECO ball valve made up to a side entry sub so there is zero risk of the ball getting hung up in the cement head assembly the way darts can. Additionally, the ball drop mechanism captures a 14” cement sample (CoreCure®) which is returned to surface with the inner string. In this way, SeaCure® with CoreCure® provides a downhole cement sample and confirmation of a quality primary cement job.
What happens if the floats fail on the casing shoe? What happens if the SeaCure® dart or ball doesn’t bump?
It’s highly unlikely that the double non-return float valves built into our SeaCure® shoes will both fail, but even in that unlikely scenario, the SeaCure® dart or ball seat provides a tertiary cement barrier. It’s highly unlikely that the dart or ball will not seat and provide the intended pressure seal leading up to rupture of the SeaCure® burst disc. In any case, we pump 2-4 barrels of “insurance” cement behind the dart or ball in the event it doesn’t bump. In a clinical SeaCure® job, this “insurance” cement is circulated out of the casing ID after the burst disc is ruptured. If the inner string can’t be sealed off, this minimal volume of top cement functions as a cap similar to the way a “poor boy” inner string’s tailing cement caps the float shoe (creating a shoe track).
It’s important to remember that – in the extremely unlikely event that everything goes wrong on a SeaCure® job – it’s still better than a “poor boy” inner string job and there are no tricky plugs to drill out.
What is QuikCure®? How is it different than SeaCure®?
QuikCure® jobs are exactly the same as SeaCure® jobs with the added benefit of minimising waiting on cement (WOC) time. After the cement job is completed, the inner string is sealed off via a dart or ball drop and the burst disc is ruptured, allowing the inner string contents to be circulated out of the casing ID. On a QuikCure® job, at this stage a heat sweep is circulated through the inner string to elevate the temperature inside the casing. For every 4.5 degrees Celsius increase in temperature, the cement set time is halved. We estimate up to 90% reductions in WOC time are possible. Check out our Case Studies for additional information.
Can you estimate the potential WOC time savings associated with QuikCure®?
Sure can. For QuikCure® jobs, we pre-install a temperature gauge on the Cam Actuated Running Tool (CART) ball valve exit to enable an ROV to relay the temperature of the water exiting the top of the casing ID. We have partnered with the University of Aberdeen to create SimCure, modelling software that estimates the set time for a slurry given the particulars of the well design and the observed temperature of the heat sweep exiting the CART.
How can you produce the heat sweep fluid on my rig?
We have seen that simply circulating sea water through a simple bean choke or the rig’s shear gun lines provides temperatures up to 65 degrees Celsius, which has been enough to reduce WOC time from 18 to 3 hours. We have also utilised a fit for purpose steam generation unit and plate heat exchanger. It’s important to note that any temperature increase will set the cement quicker and save rig time.
What’s the catch?
There really isn’t one. Our Cure services bring all of the benefits of “stabbed-in” inner string cementing to the subsea environment. Our SeaCure® cementing system is robust and field proven. With the additional QuikCure® and CoreCure® services, we can easily save several hours or even days of rig time, depending on the unique challenges of your project. At worst, our Cure services are better than conventional cementing techniques. At best, we are redefining the technical limit for your well and delivering substantial cost savings straight to your bottom line.
Where can I learn more?
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