BHGE推出的MILLITE轻型压裂桥塞采用新的工程材料，能够大幅缩短磨铣时间。
编译 | 惊蛰
近日，BHGE宣布推出了MILLITE轻型压裂桥塞，MILLITE桥塞完全由工程合金材料制成，不含任何重金属或陶瓷部件。该桥塞的耐磨设计与防预置设计避免了提前坐封的风险，安全下入速度可达600英尺/分钟（183米/分钟）。现场就绪的电缆适配器组件简化了组装过程，此外，桥塞的摩擦卡瓦锚定系统与封隔组件可在高达10000psi的压力下牢牢地将其锚定在套管中。
BHGE公司非常规完井技术产品总监Chris Johnson表示:“非常规油气市场需要不断创新，以提高效率并降低成本。MILLITE桥塞独特的轻质合金材料为业内提供了诸多全新功能，可进一步加速压裂后的修井作业，从而使客户能够更快地投产。”
就常规技术来说，复合材料、铸铁与陶瓷材料之间的过渡经常会导致钻塞时机械钻速的波动，加快铣刀的磨损，在某些情况下，还会造成额外的起下钻作业，提高成本。MILLITE桥塞磨铣更快速、更轻松、扭矩更小，有助于延长马达寿命并降低钻塞成本。MILLITE轻型压裂桥塞完全采用坚固的工程合金材料制造，比常规桥塞材料轻70％，可平稳地将其钻穿，并轻松返出碎屑，从而降低作业成本，使客户更快地获得第一桶油。
压裂桥塞的设计与材料特性会影响压裂后将其从井筒中移除的速度与效率，常规压裂桥塞中含有坚硬、沉重的组件，比如铸铁卡瓦与陶瓷镶齿，这使得压裂桥塞很难被磨碎，而且更难将磨铣碎屑循环出井筒。MILLITE轻质压裂塞的比重仅为1.8，其网状结构可产生较小的切屑，从而能够提高碎屑返出率，最大限度地减少洗井需求，并加速压裂后的修井作业。与常规桥塞相比，其紧凑的设计也降低了每个桥塞的总碎片体积。
而且，当MILLITE桥塞运达现场时，自带的现场就绪电缆适配器套件简化了装配流程。无需特殊螺钉或工具。在钻塞期间，该桥塞的耐磨设计与防预置设计避免了提前坐封的风险，安全下入速度非常快，可节约大量作业时间。可靠的摩擦卡瓦锚定系统与封隔组件可形成稳固的密封，能够在压裂过程中稳定的保持住压力。目前，该MILLITE桥塞可以应用与非常规油气井，射孔桥塞联作完井作业，井底压力低的油藏以及大位移井。
案例分析
在最近的一次作业中，美国科罗拉多州的一家公司在射孔桥塞联作完井作业中使用了MILLITE轻型压裂塞，希望缩短修井时间，并降低连续油管的循环成本。该井的测量深度为10800英尺（3292米），水平段长度为4400英尺（1341米），完井设计要求等距离坐封22个桥塞。这些桥塞的平均下入速度为750英尺/分钟(229米/分钟)。压裂作业完成后，在没有马达停转或短起下的情况下，对MILLITE桥塞进行了磨铣，平均钻塞时间仅为5分钟。钻塞产生的碎屑极小，留下极少的碎屑，这些碎屑很容易从井筒中循环出来，且不需要特殊化学品。
在俄克拉何马州，客户在低温低压井中进行射孔桥塞联作完井作业，当时他正在寻找一种方法来加快钻塞速度，并提高碎屑清除效率。由于井底压力较低，井眼存在明显的举升难题，清洗井眼难度较大。
在了解了客户面临的挑战后，作业人员推荐其使用MILLITE轻型压裂桥塞与SPECTER低温分解压裂桥塞的组合，以最大限度地减少井筒内的碎屑。与含有铸铁卡瓦和陶瓷镶齿等硬而重的组件的常规桥塞不同，MILLITE轻型压裂桥塞通体由一种坚固的工程合金材料制成，比常规桥塞轻70%，磨铣更加顺畅，可更容易、更彻底地清除碎屑。
此外，这口特殊井的井底温度低至150°F（66°C），会造成分解速率的降低，从而需要额外的铣削与清除，才能去除无法分解的组件。基于温度与盐度的变化，选用SPECTRE低温分解桥塞作为井底段的封堵工具，即使在低温环境下，压裂后该桥塞也能完全分解。该井总垂深为9487英尺（2892米），水平段长度为10015英尺（3053米）。完井设计要求等距离坐封31个MILLITE桥塞与31个SPECTRE低温桥塞。
除了比常规复合材料桥塞更轻、更紧凑之外，MILLITE轻型压裂桥塞还具有耐磨与防预置性能，避免了下入期间的提前坐封风险。因此，客户能够以300英尺/分钟（91米/分钟）的平均速度部署MILLITE桥塞。当投球以15桶/分钟的速度泵入至桥塞上时，可观察到明显的压力信号，证实桥塞在处理分流过程中保持锚定状态。?
在压裂作业完成后，下入铣削钻具组合，并使用3.375寸外径的Versa Drive过油管马达与Vanguard钻塞钻头铣削所有MILLITE桥塞。由于井底压力较低，因此在钻井过程中利用氮气提升井筒内流体，以保持循环。尽管使用了大量的氮气，MILLITE桥塞仍然能够保证碎屑成功循环出井筒，并且在零停钻以及零额外马达宕机下，成功完成该项作业。因为该井的深度与水平段长度过长，钻具组合无法到达井底，但是由于客户选择使用了SPECTRE压裂桥塞，从而他们能够继续开采更深的层位。
Constructed completely of an engineered alloy material, the MILLITE plug does not contain any heavy metal or ceramic parts. The plug’s wear- and preset-resistant design virtually eliminates preset risks, enabling safe run-in rates in excess of 600 ft/min (183 m/min). A field-ready wireline adapter kit simplifies assembly, and the plug’s proven friction-slip anchoring system and packing element keep it firmly anchored in the casing at pressures up to 10,000-psi.
“The unconventional market requires continuous innovation to drive increased efficiencies and lower costs,” Chris Johnson, Product Line Director, BHGE Unconventional Completion Technologies, said. “The MILLITE plug’s unique lightweight alloy material offers something completely new to the industry to further accelerate post-frac interventions so that customers can start producing sooner.”
Transitions among composite, cast iron, and ceramic materials often cause rate of penetration fluctuations as each plug is milled, accelerating tool wear and, in some cases, necessitating extra trips. The MILLITE plug mills more rapidly and more easily with less torque, helping to improve motor life and reduce drilling costs. With a specific gravity of only 1.8, the plug’s fine debris can float up and out of the well without the aid of additional cleaning sweeps or costly chemicals. At under 13 in. long, its compact design also contributes to a lower overall volume of debris per plug compared to standard plugs.?
Built completely out of a robust, engineered alloy material that is 70% lighter than conventional plug material, the MILLITE? lightweight frac plug drills out smoothly and flows out easily to cut costs and get customers to first oil faster.
Although the design and the material properties of frac plugs affect how quickly and efficiently they can be removed from wellbores post-fracturing, conventional plugs contain hard, heavy components like cast iron slips and ceramic buttons that make them tough to mill out, and their debris even tougher to circulate out.
The MILLITE plug’s compact design features proven friction-based slips—versus heavy cast iron slips or ceramic buttons—to keep it firmly anchored in the casing at pressures up to 10,000 psi (690 bar).
With a specific gravity of only 1.8, and a lattice structure that generates smaller cuttings, the MILLITE lightweight frac plug improves debris flowback, minimizing cleanout requirements and accelerating post-frac intervention. Its compact design also contributes to a lower overall volume of debris per plug compared with standard plug debris volumes.
And, when MILLITE plugs arrive on location, their field-ready wireline adapter kit simplifies assembly. No special screws or tools are required. During run-in, the plug’s wear- and preset-resistant design virtually eliminates preset risks, enabling safe run-in rates in excess of 600 ft/min (183 m/min). A proven friction-slip anchoring system and packing element create a reliable seal that reliably holds pressure during fracturing.
Applications
- Unconventional oil and gas wells
- Plug-and-perf completions
- Reservoirs with low bottomhole pressure
- Extended-reach laterals?
On a recent job, an operator in Colorado performing plug-and-perf completions used MILLITE lightweight frac plugs to minimize intervention time and reduce coiled tubing cycling costs. The well had a measured depth of 10,800 ft (3,292 m) and lateral of 4,400 ft (1,341 m), and the completion plan called for a total of 22 plugs to be set at regular intervals. The plugs were deployed at an average speed of 750 ft/min (229 m/min). After fracturing operations were complete, the MILLITE plugs were milled without any motor stalls or short trips, and the average millout time was only five minutes per plug. The plugs milled out with significantly smaller cuttings, leaving minimal debris, which easily circulated out of the wellbore, without the need for specialty chemicals.
A customer performing plug-and-perf completions on a low-temperature, lowpressure well in Oklahoma was looking for a way to accelerate plug milling and improve debris removal. Because of the low bottomhole pressure, the well had significant lift issues, making hole cleaning an arduous process.?
Understanding the customer’s challenges, Baker Hughes, a GE company (BHGE), suggested running a combination of MILLITE? lightweight frac plugs and SPECTRE? low temperature disintegrating frac plugs to minimize debris in the wellbore.?
Unlike conventional plugs that contain hard, heavy components such as cast iron slips and ceramic buttons, MILLITE lightweight frac plugs are built completely out of a robust, engineered alloy material that is 70% lighter than conventional plugs—enabling smoother milling and easier, more complete debris removal.?
Futhermore, this particular well had bottomhole temperatures as low as 150?F (66?C), which can decrease the rate of disintegration resulting in the need for additional milling and cleanouts to remove the non-disentegrating components. SPECTRE low temperature disintegrating plugs were selected for the bottom portion of the well, as they react based on temperature and salinity, and completely disintegrate downhole after fracturing, even in low temperature environments.
Flawless execution
The well had a total vertical depth of 9,487 ft. (2,892 m) and a lateral length of 10,015 ft. (3,053 m). The completion plan called for a total of 31 MILLITE plugs and 31 SPECTRE low temperature plugs to be set at regular intervals.?
In addition to being lighter and more compact than conventional composite plugs, MILLITE lightweight frac plugs are also wear- and preset-resistant, virtually eliminating preset risks during run-in. Because of this, the customer was able to deploy the MILLITE plugs at an average speed of 300 ft/min (91 m/min).? Clear pressure signatures were observed as balls were landed on the plugs at 15 bbl/min, confirming the plugs remained anchored in place during treatment diversion.?
After fracturing operations were complete, a milling bottomhole assembly was deployed and all of the MILLITE plugs were milled using a Versa-Drive? 3?- in. outer diameter (OD) through-tubing motor and Vanguard? plug bit.? Because the well had low bottomhole pressure, nitrogen was used to lift the well to maintain circulation while drilling out. The MILLITE plugs enabled the successful circulation of debris from the well, despite extreme amounts of nitrogen being utilized, and the job was successfully completed with zero stalls or additional motor trips.?
Due to the well’s depth and lateral length the drill out assembly was unable to reach the toe of the well, however because the customer opted to use SPECTRE disintegrating plugs, they are able to continue producing from the lower zones