Unity推出的新型封堵弃井技术TACTT能够大幅提高作业效率，降低成本！

编译 | 惊蛰

近日，Unity公司研发推出了一种创新型的新技术，可在封堵弃井作业前，在作业船上对油井进行压力测试，从而提高安全性，降低作业成本。

这家总部位于阿伯丁的公司推出了临时弃井封盖测试工具（TACTT），用于支持北海南部的弃置项目，目前已经得到了大范围应用。

在同类产品中，该技术是首个能够密封任何类型、任何尺寸临时弃井（TA）井盖的工具。它可对密封件进行压力测试，以确保油井的密封，然后在TA封盖下方测试与释放压力，并在适当位置形成可靠的二级密封。在开放水域，无需钻机，从船上便可利用电缆部署该工具，从而大幅降低了成本。

在Spirit Energy项目期间，从作业船上部署了TACTT设备，将其锁紧、密封在TA封盖上，并对该密封进行压力测试。然后进行第二次压力测试，以验证TA封盖回压阀的下方不存在压力。一旦确认了完整性，作业者就可以安全地继续作业，移除封盖，完成封堵弃井作业。

利用该技术，作业者能够掌握TA封盖下方的压力积聚情况，并将其纳入弃置设计，要么继续用船舶进行修井作业，要么将TACTT安全阀保留在原位置，以备后续的钻机作业。无需钻机，仅依靠作业船进行封堵弃井作业，可缩短作业周期，更具经济效益。Unity公司的技术可安全地确认重新进入已钻井眼时不存在回压，有助于实现上述类型的干预作业。

英国石油与天然气管理局最近的一份报告预估，英国大陆架所有的退役成本中，45%来自于封堵弃井，目前该行业正努力将这项的占比降低至35%。业内普遍认为，与基于钻机的干预作业相比，基于船舶的干预作业可节省30%至50%的成本。

Unity首席执行官Gary Smart表示：“正如人的生老病死，退役也是任何一口井必经的终结阶段，尽管油气行业大费周章的开发出各种方法以延长油气井的生产寿命，但我们还必须进一步寻求创新技术，以帮助作业者履行他们的封堵弃井义务。”

?“作为欧洲最大的井筒完整性专业公司，我们有能力运用我们的工程技术应对这一挑战。我们根据作业者的需求开发出了TACTT，因为目前市场上还没有专门的解决方案，可以在移除TA封盖后，对海上的临时弃置井进行压力测试。”

?“我们的技术可以节省大量的作业成本，特别是在全区域的船舶作业中，可将其用于多口井的压力测试、测量以及弃置准备。这项技术能更好地了解每口井的具体情况，从而更安全、更经济地进行封堵弃井干预作业。”

Spirit能源公司钻井与油井总监Olav Log表示：“根据英国政府的规定，我们利用Unity公司的TACTT，在北海成功完成了两口井的弃井作业。该工具避免了重新进入临时弃置井的所有相关风险，并且利用船舶即可进行部署，为项目节约了大量资金。”

?“最初，TACTT技术是根据我们的规格而设计，并在早期利用北海的钻井平台成功部署。这一最新的研发项目为船舶部署提供了更多机会。”

案例分析

近日，Unity拆除使用了30年的海底TA封盖，以进行后续的弃井作业。位于北海南部荷兰海域的一口海底油井已经停产30多年。该公司希望弃井，因此需要一套工具来形成密封，并取出用于临时弃井（TA）的封盖。

该13.375寸TA封盖需要一个密封在封盖上的工具，以便刺穿回压阀（BPV），使压力通过钻柱向上释放。在现有BPV无法重新密封的情况下，还需另一种控制压力的方法，因此，可以选择将该系统留在原位，并在以后重新锁定。

Unity公司设计了一款提拉工具，其功能有：

• 定位并锁紧TA封盖上的扭矩销；
• 在TA封盖上形成双重密封系统，用于压力控制；
• 在刺穿TA封盖上的BPV之前，激活该工具后，可从环空侧与钻柱侧，对密封件进行测试；
• 在BPV未重新密封的情况下，结合二级内部密封，控制下方的压力；
• 提供一种方法来判断原始BPV是否打开/密封；
• 可直接拉断连接，使该工具保持在TA封盖上，确保井筒完整性，以便后期利用回收工具进行回收；
• 操作简单，包括：向左或向右旋转、提拉或下放重物。

与业内同类工具相比，Unity公司开发出的工具性能更卓越，用于回收其它的临时弃井封盖。实现快速可靠的油井再入作业，对节省作业时间至关重要，因为自升式钻机、工作人员与设备每天的成本高达15万英镑。该工具安全、环保地重新进入了三十多年从未进入的井，实现了弃井作业，确保作业者履行了其法定义务。

A pioneering new method of pressure testing suspended mudline wells from a vessel, prior to P&A activity, developed by Unity, is set to deliver improved safety and cost savings following a successful project for Spirit Energy.

The Aberdeen-headquartered company’s Temporary Abandonment Cap Test Tool (TACTT) was deployed to support an end of life project located in the Southern North Sea.

It is the first technology of its kind, which is able to seal on to any type and size of temporary abandonment (TA) cap, pressure test the seal to ensure well containment, then test and vent pressure from below the TA cap and leave a reliable secondary seal in place. It can be cable deployed from a vessel through open water, rather than using a rig, providing significant cost savings.

During the project for Spirit Energy, the TACTT was deployed from a vessel, latched and sealed on to the TA cap and the seal was pressure tested. A second pressure test was then performed to provide verification of zero pressure under the TA cap’s back pressure valve. Once integrity was confirmed, this allowed the operator to safely continue with removal of the cap and complete their P&A operations.

The technology allows the operator to understand the amount of pressure accumulation below the TA cap and to accommodate this in their plans for decommissioning, either continuing with vessel-based intervention or leaving the TACTT safety valve in place and returning with a rig at a later date if necessary. Vessel rather than rig-based P&A work is faster and more cost effective and Unity’s technology can help to enable this type of intervention by safely confirming no back pressure for well re-entry.

A recent report by the Oil and Gas Authority estimated that 45% of all decommissioning expenditure in the UK Continental Shelf is through P&A of wells and the industry is currently striving to reduce this spend by at least 35%. It is generally acknowledged that vessel-based intervention can save between 30%-50% in costs compared to rig-based intervention.

Gary Smart, Unity CEO said: “Decommissioning is the inevitable end-stage of any well, and although the industry is developing many solutions to extend producing life, we must also look to innovate further new technology to support operators’ P&A obligations.

“As Europe’s largest well integrity specialist, we are well-placed to apply our engineering skills to meet this challenge. We developed the TACTT in response to operator demand, as there was no specific solution available on the market to pressure test suspended mudline wells behind their TA caps prior to removal.

“Our technology can open doors to huge operational savings, particularly by using it on multiple wells in region-wide vessel campaigns to pressure test, survey and prepare them for abandonment. This technology delivers a better understanding of each well’s individual conditions, allowing safer and more cost-effective P&A intervention.”

Olav Log, director of drilling and wells at Spirit Energy said: “Unity’s TACTT allowed Spirit Energy to successfully abandon two North Sea wells in line with UK Government regulations. The tool removed all risk associated with re-entering a suspended well and the ability to deploy by vessel provided significant project savings.

“The TACTT technology was originally designed to our specifications and successfully deployed from a rig in the North Sea in 2014. This latest development allowing for vessel deployment opens up further opportunities.”

Case Study： Removing 30 Year Old Subsea TA Caps to Facilitate Well Abandonment

A subsea well in the Dutch sector of the southern North Sea had been suspended for over thirty years. The operator wished to abandon the well so a suite of tools were required that would seal on and pull a set of temporary abandonment (TA) caps.

The 13-3/8” TA cap needed a tool which would seal onto the cap in order to stab a back pressure valve (BPV) to vent any pressure up through the drill string. A secondary means of holding pressure in the event that the existing BPV would not re-seal was also required, with the option to leave the system in place if needed and re-latch on at a later date.

Solution: Unity designed a Pulling Tool which could:

• Locate and latch a torque pin on the TA cap.
• Provide a double sealing system on the TA cap for pressure containment.
• Provide a means of testing the seal once energised, from both the annulus side and drill string side, prior to stabbing the BPV on the TA cap.
• Incorporate a secondary internal seal that would retain pressure from below in the event that the BPV did not re-seal.
• Provide a method of telling if the original BPV was opening/sealing.
• Allow a straight pull to disconnect, leaving the tool holding integrity on the TA cap for a return trip at a later date with a retrieval tool.
• Enable simple operation, including rotate left or right and pull up or set down weight.

The efficiency of the design and development of the first tool and its successful performance led to the development of further specialised tools for the recovery of other temporary abandonment caps. Quick and reliable well re-entry was achieved, which is vital for saving operational time, costing upwards of ￡150,000 per day on the jack-up rig, crews and equipment. The tool enabled the safe and environmentally secure? re-entry to a well not accessed for over thirty years so it? could be abandoned, ensuring the operator met their? statutory obligations