PAC polymers go before PHPA polymers and dry polymers before liquid polymers. Adding polymers before the bentonite has thoroughly mixed can cause balling. The order of mixing also plays a role in the science of drilling mud. A poor suspension characteristic can consume more energy to circulate the drilling mud through the system, thus slowing down the drill's progress. In some cases, it can also cause the pipe to stick in the borehole. Inadequate lubrication can cause drill head damage and inefficiency. Even if frac-out or borehole collapse are avoided, the project may take longer and cost more than necessary. While it is possible to complete an HDD project with a generic drilling mud mix, it is often not the most efficient method, and it can lead to major problems like frac-out. The more thorough the geotechnical investigation of the proposed HDD path, the more precisely the ideal drilling mud formula can be determined. The science behind making the best mixįinding the right drilling mud mix for any project starts with an understanding of the soil conditions. Polymers with larger molecular weights are most suitable for rocky soil. Partially hydrolysed polyacrylamide (PHPA) polymers work well in reactive clays instead of bentonite. Polyanionic cellulose (PAC) is common in sand and cobbles. Several additives are available, and each is suited for different conditions. The final constituent of drilling mud is an additive. pH should be kept between 8.5 and 9.5, while calcium content should be below 100 parts per million (ppm). When using water-based drilling mud (WBM), the quality of water also influences its performance. ( Read also: Bentonite and the Use of Drilling Mud in Trenchless Projects.) It is the bentonite which forms a cake-like film on the inside walls of the borehole to stabilize it. The main secondary ingredient is bentonite, which is a mineral found in clay beds. Other components are added to this base in order to achieve the desired characteristic. The primary constituent of drilling mud is either oil (called synthetic-based or low toxicity oil-based mud) or water.
The study highlights the importance of drilling fluid for the success of an HDD project. The mud mixing system is designed to handle 45m/h.A joint study by the University of Illinois and the Illinois Department of Transportation explored the approval of HDD as a construction method in specific applications. The 200GPM (45m/h) mud mixing system is mainly adapted to 400-800L/min mud pumps and 80-160 tons HDD directional drilling rig rigs. The designed processing capacity of the mud mixing system is 80m/h.Ĥ. The 350GPM (80m/h) mud mixing system is mainly adapted to mud pumps with a flow rate of 1200-1500L/min and HDD non-excavation directional drilling rigs with a pullback force of 60-200 tons. The designed processing capacity of the mud mixing system is 120m/h.ģ. The 500GPM (120m/h) mud mixing system is mainly adapted to mud pumps with a processing capacity of 2000-2500L/min and HDD non-excavation directional drilling rigs with a return force of 250-350 tons. The mud mixing system is designed to handle 240m/h.Ģ. The 1000GPM (240m/h) mud mixing system is mainly adapted to a mud pump with a flow rate of 4000L/min and an HDD non-excavation directional drilling rig with a return force of 500-800 tons.
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