What Are the Most Common Types of Drilling?

Drilling is the first step in modern oil, gas and geological operations. These industries depend on effective drilling to keep operations running, and without it, there is no extraction and processing. Global oil production is over 100 million barrels per day. The key to this rapid production rate? Advanced drilling methods. 

Drilling technique influences output and changes based on formation type, target depth and operational goals. 

1. Vertical Drilling

Vertical drilling was the founding type of drilling in oil and gas work. In this technique, the wellbore goes straight down into the ground, toward the target reservoir. It's the simplest and most cost-effective option for exploratory wells. Vertical methods are best suited for formations directly beneath the drilling site or when single-zone extraction is enough to meet operational needs. 

While simple, vertical drilling is central in early-stage projects and smaller-scale operations. It doesn't need the specialized equipment, high power output or surface logistics of more advanced drilling methods. 

However, vertical drilling is limited — operations often need multiple wells to access the same area that one horizontal well can connect.

2. Cable Tool Drilling

Cable tool, or percussion, drilling was one of the most common drilling methods, but it is now reserved for shallow oil exploration and water wells. It relies on a heavy bit suspended by a steel cable that repeatedly strikes the formation. This process breaks rock and sediment through impact.

Percussion drilling is less common than rotary drilling, but it's still valued for its simplicity, low energy requirements and ability to operate in consolidated formations. This type of drilling generates minimal circulation pressure, which helps protect groundwater zones and provides a controlled pace in unstable soils. However, cable tool operations have slower penetration rates and need regular casing and debris removal to maintain hole stability. 

3. Rotary Drilling 

Another popular drilling method is rotary drilling. Thanks to its efficiency and depth capability, it's the industry standard for land and offshore applications. In rotary drilling, a rotary table or top drive continuously spins the drillstring. This turns the bit as drilling fluid circulates down the pipe and back up the annulus. It's a closed-loop design that removes cuttings, cools the bit and stabilizes the borehole. Operations can easily maintain pressure control, even in complex formations.

Rotary drilling can quickly reach several miles below the surface while staying precise. Engineers choose the bit type, drilling fluid and bit weight to match the deposit formation's hardness and porosity. Continuous operation reduces downtime and manual intervention, which is ideal for high-production wells and directional needs. 

4. Directional and Horizontal Drilling

Instead of boring straight down, directional drilling operations deviate the wellbore to reach multiple targets from a single surface location. One form of this is horizontal drilling. In it, operators turn the wellbore horizontally once it reaches the reservoir. Operators can follow thin seams laterally and access a larger production zone without further affecting the surface. 

Directional drilling techniques are more efficient at resource recovery, especially in shale plays and tight formations. It's essential to model the build, hold and drop sections before directional drilling. 

Engineers must map out how the bore deviates and stabilizes during the process. They also have to consider drilling fluid and the effects of high angles to minimize friction and prevent cuttings buildup.

5. Dual-Wall Reverse-Circulation Drilling 

Dual-wall reverse-circulation (DWRC) drilling is one of the most popular drilling methods in geology. The system uses two concentric drill pipes to facilitate faster production. Drilling fluid travels through the outer annulus, while rock cuttings return upward through the inner pipe. Its closed-loop design prevents contamination and keeps samples intact. Operations get better rock samples while enhancing penetration rates. Since cuttings move through the inner pipe, users may be able to reduce surface casing requirements. 

6. Electro-Drilling

Electro-drilling is an emerging method. It uses high-energy electrical discharges to fracture rock instead of mechanical force. Each pulse generates a shockwave that shatters the formation. Since the bit isn't penetrating manually, you protect it from wear. It's a promising technique for hard rock and geothermal applications, which often cause rapid bit wear. 

However, this method is still developing. Delivering high electrical power downhole requires durable, high-cost cables that can withstand pressure and heat. Integrating this system with drilling fluids and hole cleaning is complex. Additionally, there is little standardization and operators have to weigh advanced technology with higher costs and risks. For now, electro-drilling is a specialized technique.

Other Specialized Drilling Methods

Specialized methods come into play for niche applications. Industries might use:

• Air or gas drilling: These methods operate underbalanced, using compressed air instead of mud for faster progress in dry or hard formations.
• Reverse circulation: This method offers effective cuttings transport for large-diameter boreholes. 
• Core drilling: Core drilling extracts cylindrical rock samples. The samples are high-integrity and make evaluations much more accurate.
• Coiled tubing: This technique uses a continuous steel coil instead of a drill pipe. Operators can drill, clean out or re-enter wells without tripping. It's ideal for underbalanced wells and tight spaces where teams must minimize rig-up time. 
• Slimhole: Slimhole drilling has smaller-diameter boreholes and lighter equipment to reduce cost, environmental impact and drilling fluid volume. It's becoming more common in geothermal, exploration and low-impact drilling environments.

Precision sealing and shock absorption are essential in each of these systems. To protect equipment from abrasion and vibration, they require air seals, sample-integrity seals and core-barrel cushions.

Choosing a Drilling Method

Once you understand the types of drilling techniques, you have to know when to apply them. Consider formation type, target depth, sampling goals and constraints before starting. 

Engineers must weigh the benefits and trade-offs to protect the operation. Learn more about each method below:

• Vertical: This type of drilling is useful for affordable, efficient appraisal and exploratory wells. Teams can use it when they do not need multi-zone access and the reservoirs are directly beneath the surface. Vertical drilling is often used as the first step in field development.
• Cable tool: The simplest method, ideal for groundwater exploration and shallow wells. The impact-driven design provides precise control and minimal fluid circulation. Use it when trying to protect groundwater and maintain low equipment demands. Its slower penetration rates limit its use in deep or large-scale oilfield projects.
• Rotary: Choose rotary drilling for gas and oil production. It can reach significant depths and offers extremely consistent penetration. Rotary methods also provide superior pressure control and high-rate cuttings removal. They adapt well to different formations and are compatible with vertical and directional bore paths.
• Directional: Directional methods excel when operations need to access multiple zones from one surface location or when they're working around complex structures. Use directional drilling when working with unconventional materials like shale or with the coalbed method. They perform effectively and efficiently, with minimal surface disturbance.
• DWRC: Choose DWRC for mineral and geological sampling. It preserves sample integrity and cleanliness. It's also effective in oilfield work when teams need to evaluate complex formations before production drilling.
• Electro-drilling: Electro-drilling is a newer method, used for work involving geothermal, deep and hard-rock wells. The promise of low-bit wear and efficient rock fracturing has significant potential as the technology develops.

What Are the Most Common Types of Drill Bits?

Proper bit selection is critical for rotary and directional drilling. A drill bit affects the rate of penetration (ROP), equipment wear and fluid performance — all critical factors for drilling. The three main designs are polycrystalline diamond compact (PDC), roller-cone, and impregnated diamond bits.

Polycrystalline Diamond Compact (PDC)

Thanks to their speed and longevity, PDC bits are the preferred choice for modern rigs. They use diamond cutters fused to a tungsten substrate, which results in consistent sharpness and a high ROP in medium-hard to hard formations. PDC bits offer excellent wear resistance and consistent performance at high rotation speeds. Use them for shale, limestone and dolomite formations.

Roller-Cone

Roller-cone bits, also called tri-cone bits, have three rotating cones with steel or tungsten carbide teeth. As the cones roll, they crush and gouge the formation. They're a reliable, versatile tool in unpredictable and mixed-hardness areas. Use them on everything from soft clays to interbedded sandstone and limestone.

Impregnated Diamond 

Impregnated diamond bits are used in ultra-hard or abrasive formations where conventional bits quickly wear out. Instead of fixed cutters, they use bits embedded with synthetic diamonds. This design gradually grinds through rock and can tolerate extreme temperatures and differential pressures. Geothermal drilling, deep exploratory wells and coring operations all use these bits.

Drilling Fluids and Elastomer Compatibility

No matter the drilling method, you must choose the fluid carefully. These fluids are essential for drill function, working to cool the bit, remove cuttings, lubricate and control formation pressure. Fluid options typically include water-based, oil-based and synthetic-based — each with different properties that affect the life of elastomer components.

Water-Based

These fluids are water mixed with added clays, polymers and weighting materials. They're some of the most common fluids and are more environmentally friendly than other options. Choose water-based fluids for shallow to medium-depth wells or formations with moderate temperature and chemical exposure. However, the high moisture content can cause hydration and swelling in certain elastomers. 

Oil-Based

Oil-based fluids use diesel, mineral or synthetic oil. These oils provide excellent lubricity and thermal stability, especially compared to water-based options. They're ideal for deep or high-temperature wells or drilling through reactive shales. A drawback is that the same hydrocarbons that protect the wellbore can extract plasticizers from elastomer compounds, resulting in shrinkage or embrittlement when used with the wrong material.

Synthetic-Based

Synthetic-based fluids combine the strength of water and oil-based options. They have the lubricity and heat resistance of oil and the lower toxicity of water. Choose synthetic-based fluids for offshore or environmentally sensitive operations. Synthetic options use a mix of synthetic esters, olefins and internal lubricants, which expose elastomers to complex chemical interactions. Operations will need components with extra resistance to hydrocarbons and additives.

Technology Driving Drilling Forward

As energy demand grows and accessible reservoirs decline, operators are investing in new drilling systems to optimize extraction. 

Automation, sensor networks and artificial intelligence (AI) analytics optimize well trajectory and penetration rate. Integrated sensor networks deliver real-time data into surface systems, letting engineers monitor drilling information constantly. They can make faster, better decisions about weight on the bit and equipment condition. The goal is to reduce downtime and improve efficiency and safety on-site.

Tools like rotary steerable systems (RSS) can adjust direction without stopping rotation. Combine them with measurement-while-drilling (MWD) and logging-while-drilling (LWD) tools for better precision. RSS technology can navigate through thin payzones and obstacles as it maintains borehole smoothness. These tools improve efficiency in extended-reach and deepwater wells. 

All these innovations bring new challenges. Upgraded technology means more complex mechanical loads and higher temperatures for equipment to wear under. Elastomers must now deliver better chemical resistance, flexibility and stability under these more intense conditions. Look for custom-engineered elastomers to handle these new obstacles without compromising performance.

How Global Elastomeric Products, Inc. Complements Drilling

Whatever the drilling method, every system needs reliable sealing, insulation and vibration control. Global Elastomeric Products, Inc. engineers elastomer components that perform under the unique demands of your application. Our solutions work for each of the main drilling types:

• Vertical: Global offers surface gaskets and circulation seals that maintain pressure and prevent fluid loss for straight-well projects.
• Cable tool: Use packer and swab cups to maintain fluid retention and borehole stability. We also offer shock-isolating elements that absorb repetitive impact.
• Rotary: Maintain circulation integrity and prevent fluid leakage with seals and surface gaskets.
• Directional: If you use tools in high-temperature, high-pressure (HP/HT) conditions, use motor and RSS seals, stabilizer pads and vibration-control elastomers that keep performance consistent in long-reach wells. 
• DWRC: DWRC systems rely on swivel, return-path seals, and abrasion-resistant liners to withstand high-velocity cutting and abrasive slurries.
• Electro-drilling: Global offers dielectric and heat-stable elastomers that insulate electrical housings and maintain precision sealing near sensitive electronics.

Support Your Drilling Techniques With Custom Elastomer Solutions

Every drilling operation is unique, so you need components built for the exact job. Whatever your system, the right elastomer design can make all the difference in performance. At Global Elastomeric Products, Inc., our in-house engineers work directly with drilling and production teams to design and manufacture custom rubber components. 

With over 50 years of experience serving the oilfield industry, you can count on us to help improve equipment uptime and material compatibility. All Global Elastomeric Products, Inc. products are supported by in-house design engineering, custom molding, and ISO 9001 certifications. We prioritize quality control, from concept to completion. 

Our products are proudly made in the USA, and we offer quick turnaround, free quotes and a defect-free workmanship guarantee on every order. Get your quote today!