The EXACT™ tool is a fully annulus‑operated combined multi‑cycle circulating and tester valve. This in itself reduces potential leak paths. The ball valve allows the well to be shut‑in downhole, and the circulating ports facilitate the spotting of under‑balance or treatment fluids, and reverse and forward circulating during well kill operations.
EXACT工具是一种完全环空操作并将多周期循环阀和测试阀组合在一起的工具。这本身就可以减少了存在泄露风险的通路。球阀可以帮助进行井下关井，循环孔可以识别欠平衡或处理液，还可以在压井作业时进行反循环和正循环。EXAL中途测试工具套装是一种通过环空操作的工具，帮助作业者在高成本的作业条件下(比如深水作业)快速而有效地实施井下作业。因此，为了更快更高效地进行资源配置，也为了在类似深水等作业费用高昂地区进行井下操作，EXAL中途测试工具套装进行了充分的环操作和优化。
EXACT™工具兼具了井下关井和循环功能
It incorporates a nitrogen chamber which compensates for changes in annulus hydrostatic pressures at depth and a trap system (ARTS), which locks an operating reference pressure in the tool.
它还装载了一个氮气室，可以补偿一定深度下环空静水压力的变化和圈闭系统内所圈闭的参考压力变化。
The tool has three functional positions: ball open – ports closed; ball closed – ports closed; ball closed – ports open. The tool is governed by an indexing sleeve which works in conjunction with a ‘SmartCollet’ and interlock, and can be moved to the desired functional position by applying and bleeding annulus pressure. In‑house simulation software is utilised to determine the nitrogen pre‑charge pressure for specific downhole pressure and temperature conditions, together with the required applied operating pressure at each tool position. Importantly, as the tool is mechanically coupled, the ball and ports cannot be open simultaneously.
该工具具有三个功能位：球阀开启-循环孔关闭;球阀关闭-循环孔关闭;球阀关闭-循环孔开启。该工具通过一个分度套筒进行控制，与一个“SmartCollet”和联锁装置共同工作，可以通过施以环空压力或者释放压力，迫使其移动到任何需要的功能位置。使用室内模拟软件可以确定某一井底压力和温度条件下的氮气的充气压力和每个工具位置时所需要施加的操作压力。重要的是，由于该工具是机械耦合的，所以球阀和循环孔是并不能同时开启的。该封隔器应用环空压力破裂破裂盘，从而实现坐封。
The tool has been designed to fully operate with 2000 psi applied annulus pressure. It is important to leave as large an operating window as possible to activate other annulus operated tools in the BHA; in particular rupture disk fired PVT samples, which will generally be set‑up to activate from 2500 psi (upwards) applied annulus pressure. This tool is flexible and efficient, requiring minimal cycles (maximum 4), to get from one of the above functional positions to any other, and there are no waiting times between cycles.
该工具的设计作业环空压力为2000psi。留一个尽可能大的操作窗口来满足井底钻具组合中的其他环控操作非常重要;尤其是破裂盘破裂式PVT取样器PVT，该操作的触发通常设定为2500psi(向上)作用于环空的压力。该工具既灵活又高效，需要最少的循环动作(最多为4个)，就能从上面任何一个功能位置变换到另外一个功能位置，而在循环动作之间没有等待时间。
The ball can withstand 15 000 psi differential from above and below and can be opened with 7500 psi differential from above or below. The ports can withstand circulation rates in excess of 10 bbls/min at low back‑pressures. This is primarily due the tool being annulus operated – tubing operated circulating valves, by design, will close when at a predetermined pump rate, hence forward circulating rate is limited. EXACT can therefore reduce circulating times by more than half.
该球阀可以承受来自上下15000psi的压差，在7500psi大小的上下压差下的压差就可以被打开。该循环孔在低背压时可承受超过10bbls/min的循环速度。这主要是由于该工具具有环空操作-油管操作的循环阀，按照设计，该阀在达到预先设好的泵速时就会自动关闭，所以正向循环速度就受到了限制。所以EXACT可以减少一多半的循环次数。
Additional time savings can be realised in gas wells where with a tubing operated circulating valve, it takes longer to cycle tubing full of gas.
此外，在气井中可以节省更多的时间，因为通过油管操控的循环阀对满载气体的油管进行循环作业将会花费更长时间。
(来源：金正纵横能源翻译公司)
