What does HDD mean in directional drilling?

Horizontal Directional Drilling (HDD) is a construction technique whereby a tunnel is drilled under a waterway or other designated area, and a pipeline or other utility is pulled through the drilled underground tunnel. Directional boring is used when trenching or excavating is not practical. It is suitable for soft to hard clays, wet soils, and environmentally sensitive areas. This method avoids having to dig large pits to install jacking and boring machines.

A trenchless approach for constructing underground cables, pipes, and service conduits is known as horizontal directional drilling (HDD). It entails precisely drilling along the selected bore path and back reaming the necessary pipe using a directional drilling machine and related equipment

Three steps make up the directional drilling process:

1.Pilot Hole

Drilling a pilot hole with a small diameter is the first step. High-pressure jets and the drill bit will grind the soils ahead of the drill stem as drilling fluid is fed through the drill pipe to the drill bit. The drilling fluid will also transport the drilling waste back to the drill rig’s entrance pit. Depending on the size and complexity of the shot, there are various methods for tracking the pilot hole. Smaller shots are done using a walkover guidance system whereas the larger more complex shots have a wire line magnetics type system. In all cases, the drill stem’s precise coordinates are communicated to the location engineer via a transmitter or steering tool that is placed close to the drill head. Continuous readings are taken to monitor the drill head’s depth, alignment, and % slope.
The operator and locator will make adjustments to keep the pilot hole on the planned bore path. Depending on the soil’s current state and the amount of steering needed, the pilot hole’s pace will change. When you get to the exit location, you separate the beacon housing and bit and put a reamer in its place.

2. Pre-Reaming

The pilot hole must then be pre-reamed and enlarged to a size that will allow the product lines to be installed safely. In order to cut and remove particles and widen the hole, a reamer is pulled back and rotated as drilling fluid is pumped. The amount of cuttings removed from the hole and the current soil conditions will both influence the pre-reaming speed.
A clean and stable hole will be created using bentonite and other additives. During pre-reaming, bentonite is used to make a “cake layer” around the outside of the hole. This will aid in preventing fluid loss or infiltration and stabilizing the borehole. Additives such as polymers are used to help break up the clay soils. Any blockages inside the borehole will be avoided by a drilling fluid that is more evenly mixed.

3.Pipe Pullback

The final step is the pullback of the pipe within the pre-reamed hole. To prevent any torsional stress from the rotating drill string being transferred to the product pipe, the drill rod and the reamer will be connect to a swivel, which is used between the product line and the reamer. Drilling fluid is poured deep into the downhole to lubricate the product pipe.

How deep can directional drilling go?
These technologies are capable of reaching 10,000–15,000 ft (3000–4500 m) and may reach 25,000 ft (7500 m) when used under favorable conditions.

What Does Water Well Drilling Mean?

1. Water well drilling is the process of drilling holes in the earth’s surface for the purpose of reaching a groundwater source. There are several water sources beneath the earth’s surface but are difficult to reach and in some cases very deep. There are several drilling techniques that can be used for the purpose of drilling water wells and the most commonly used are rotary drillers that bore vertically into the earth. With the success of horizontal directional drilling (HDD) in the oil and gas industry, many in the water well industry are now turning to HDD for drilling water wells.

2. Recently, HDD in water wells has fetched good results. Earlier HDD was adapted for the purpose of remediation of contaminated sites, such as industries, military bases, and gas stations. HDD has the advantage of causing very limited surface disruption and a favorable screen-to-riser ratio. In desert areas and coastal and island communities, the aquifers that they depend on for water supply are vertically perched, thin, shallow or are sometimes buried in streams. Using vertical wells to access this water is impossible. HDD is perfect for such situations as the well can be dug from another location to access the water source.

How do you drill a Waterwell?

Begin by filling the well hole with water. Turn the drill on before inserting, and then begin drilling. The tricone bit or PDC Bit will drill through all soil types, but when it hits clay or rock the process will slow down. Don’t get frustrated, just keep drilling, and, before you know it, the first water will be hit.

Drills have different mining functions, from providing geologists with different samples of soil for analysis to facilitating the extraction of precious minerals that would otherwise be difficult to reach.

How many methods of drilling are there?

As the mining industry advances and more excavating opportunities present themselves, the number of drilling methods increases. Whether it is for exploration, production, land-clearing or geotechnical purposes, there are drilling methods that serve every mining purpose.

Rotary drilling

Rotary drilling with blades bit or roller-cone bit, in this case, the bit attacks the rock with energy supplied to it by a rotating drill stem. The drill stem is rotated while a thrust is applied to it by a pulldown mechanism using up to 65% of the weight of the machine. The bit breaks and removes the rock by either a plowing-scraping action in soft rock, a crushing and chipping action in hard rock, or a combination of the two. Compressed air or water is supplied to the bit via the drill stem. The air/water cools the bit and provides a flushing medium for the cuttings. The drill rigs typically operate in the vertical position although many types can drill up to 25 to 30 degrees inclination.

Auger Drilling
Auger drilling is the simplest form of drilling. It involves the manual rotation of a helical screw into the ground, usually by two people although auger drills can also be mounted to small vehicles. Once the auger drill is deep enough, the earth is lifted up by the blade of the screw. This kind of drill specializes as an initial geochemical reconnaissance technique, which means it is used in softer soil to find the optimal place to mount a larger drill.

Rotary Air Blasting
Rotary air blasting is the most common shallow drilling method, in which a piston-driven hammer-like object drives the drill bit into the rock, fragmenting the hard surface into chips that are then lifted to the surface via compressed air. This method is ideal for drilling multiple holes in a short period of time, and less ideal for producing geological samples because the airblasting process can compromise the quality of the rock.

Aircore
Aircore drilling involves a three-bladed drill bit with a hollow drill rod in order to penetrate loose soil and rock fragments. After the drilling is complete, compressed air is blasted through the drill rod in order to bring the cuttings to the surface. While this method is typically slower than rotary air blasting, it is more precise, meaning that the samples collected are less prone to contamination.

Reverse Circulation (RC) Drilling
Reverse circulation is a popular method for mining exploration that shares similarities with both rotary air blasting and aircore drilling. The same piston-driven hammer is used to drive the drill bit into the rock, however, the larger rigs and machinery associated with reverse circulation drilling allow for the drill bit to be driven even further into the earth. Compressed air is then used to drive the fragmented earth to the surface. This method is ideal for geological exploration, as it produces contaminant-free samples and requires less handling, resulting in cost reduction and faster turnaround times.

The benefit of reverse circulation drilling is that it will give you a more accurate understanding of the soil composition at any given depth. However, it will cost you a bit more per meter than conventional drilling. This is the most popular method in Australia and South America, where deep minerals are the most valuable export materials of the country.

For reverse circulation drilling, a dual wall drill pipe is used. Air is forced down the outer tube and injected through a port called a “side inlet swivel”. It exits just after the drill bit to force material up through the inner tube. This material is delivered upwards and collected. It can then be analyzed to get a profile of the mineral composition at the drilling depth. The bit type can be a hammer or tricone bit, but, in either case, the results are the same. You will get a clear idea of the soil composition. Reverse circulation drilling is effective until the drill head hits water or “waters out”. At this point water will enter the side inlet swivel, making it ineffective for mineral drilling exploration.

Diamond Core Drilling
Diamond core drilling is the most expensive drilling method, as it involves using a drill bit that has been fortified with industrial diamonds attached to hollow drill rods to extract a continuous cylinder of rock from several kilometers below the earth. However, this method also produces the most accurate rock samples as the entire core of a mineral can be brought to the surface as opposed to mere fragments, making it ideal for procuring records on their strength, composition, porosity, etc.

Blast Hole Drilling
Blast hole drilling is a method of drilling used to clear out large amounts of the earth and make the minerals below easier to access. It involves the drilling of holes into the earth. Explosive charges are then placed into each hole and detonated. After the explosion, the broken material is cleared and, if the drilling and blasting occurred underground, the tunnels created by the explosion are fortified to allow for safe human entry. Alternatively to explosives, gas pressure blasting pyrotechnics can also be used to displace the rock for excavation.

What is oil and gas drilling

The concept of the overall drilling process is relatively simple. There is a potential reservoir located deep beneath the earth’s surface. In order to gain access and extract oil or gas, a hole must be drilled through the various rocks, materials, and layers to reach it.

What are the types of drilling in oil and gas?

Exploration drilling is a procedure in which several test holes are drilled for the purpose of evaluating the contents of the ground in a particular area. It is conducted to find out whether or not materials of value are present and to assess the quality of those materials. The drilling of boreholes from the surface or from underground workings, to seek and locate coal or mineral deposits and to establish geological structure. The position and depth of exploration and investigation have to be selected based on previously conducted explorations such as geological conditions, structure dimensions and the character of the engineering problem, foundation depth, etc. There are a number of industries that use exploration drilling in their work, sometimes with their own drilling crews, and sometimes through companies that provide for-hire drilling services.

Geotechnical drilling is a site investigation technique designed to uncover the physical properties surrounding a construction site. Also known as geotechnical boring, this process involves evaluating the soil, rock, groundwater, and overall conditions within a given depth and location.

What’s the most important part of any structure? If you said the foundation, ding ding ding! That’s right. The whole building rests upon the foundation. No matter how strong the rest of the building is, if the foundation is unstable, the building will have some problems. They might be as small as some settling, which can result in uneven floors, cracked walls, and issues with plumbing. Serious issues with the foundation can be so severe as to require the entire structure to be torn down and rebuilt from the ground up.

Geotechnical drilling is a critical element to the investigation required to ensure that the ground is solid for the placement of the foundation. This is especially important when the construction is onshore or close to the shore. Geotech drilling is used to analyze the site. It involves collecting rock and soil samples at representative levels below the desired foundation depths, at a collection of different locations in the building site. Drilling and core samples are used to create a soil profile for the site. This profile helps to find unsafe rock, explore soil conditions, and determine the integrity of the site. When the soil profile is performed effectively, it prevents structural collapse due to earthquakes, floods, tornados, or other natural disasters.

Another benefit of geotechnical drilling is that it allows you to look for gas, oil, and mineral deposits. These are lucrative deposits and the discovery of them on a piece of land can help to make the best decisions as to how the land can be developed profitably. This can also be used by scientific researchers to investigate the constitution of ice sheets or geological structures. Material analysis of these structures is helpful, then, both for commercial and scientific exploration. Licensed and experienced drilling contractors will have the skills and background necessary to address all of your drilling needs.

Geotechnical drilling is necessary to evaluate a site before the building permit can be issues. It requires specialised equipment such as drilling rigs and other drilling devices. In addition to the hardware, a certified geotechnical engineer is required to oversee the project, and all of the drillers have to have special drilling certifications to ensure that they have the skills and experience necessary to do the job safely and produce valid results. Since geotechnical investigations are so critical to the final outcome of the project, all work must be held to the highest standards possible. It’s essential to ensure that the process is safely monitored by a qualified drilling company and that no issues pose a risk to the construction development.

Geotechnical drilling is most important for extremely heavy structures like oil rigs or buildings that have a heavy load index for the soil. Depending on the intended load of the final structure, drilling equipment might be manual, mobile, or the larger drilling rigs required for offshore oil rigs. The proper, skilled use of drilling rigs and other drilling equipment ensures that the site development is safely and skilfully monitored and that no additional complications arise during construction. This allows the site to be prepared for caissons, pilings, foundations, and other structures.

If you’d like to know more about the need for rock drilling tools in Geotechnical drilling, pls feel free to contact us. At VD Drilling, we are dedicated to offering you the highest level of rock drill tools for all of your drilling needs.