Oil and gas exploration comprises of a range of processes and methods that are used for locating potential sites for oil and gas drilling & extraction. Paul Favret mentions that while earlier oil and gas explorers depended upon surface signs like natural oil seeps, advancements in science and technology have made oil and gas exploration way more efficient over the decades. Paul has extensive expertise as a CEO, president, and founder of multiple energy, oil, and gas companies, which makes him a good candidate to talk about this topic.
Oil and gas exploration makes use of various types of drilling platforms and methods based on the type of formations, soil type, geographic location, and so on. Percussion drilling is one such widely used drilling method. In this process, a hammering bit is attached to a long cable which is then lowered into a wide-open hole, and a driller uses a tripod to support the tools. Going back and forth with the bit is helpful in loosening the soil in the borehole, which subsequently is extracted with the assistance of a bailer. The bit is removed in intervals while the cuttings are suspended in water, which tend to be removed by pumping to the surface. A steel casing is used for preventing the hole from temporarily collapsing down and protects the hole against contamination of groundwater. Percussion drilling is ideal for consolidated and unconsolidated formations, and can reach depths of about 25 meters.
Rotary drilling is another popular drilling method for up exploratory and production wells, and generally is used for wells that exceed five miles below the ground. Lightweight drills are used for drilling low-depth wells on land on this method. The equipment is mounted on a platform with a 40-meter-high derrick that features a mud mixer, an efficient injection pump, a winch, 27-meter-long pipe sections, handy engine, and a rotary table. A drag bit is used to penetrate unconsolidated sediments; while the other hand, the roller bit can drill through consolidated rock.
Paul Favret mentions that dual-wall-reverse circulation drilling is a type of rotary drilling in which a controlled flow is created by using two concentric drill pipes. Drilling fluid is pumped with the help of an outer swivel in order to reach the bottom of the bit, and subsequently ricochet upward to the main pipe. An internal pipe carries all cuttings upward. Such a drilling approach even facilitates geologic sample collection and samples are typically delivered through the cyclone created at the surface. Dual-wall-reverse circulation drilling is known to be compatible with both percussion and rotary drilling methods.
Electro-drilling has recently become quite popular. Under this method, winches and rotary tables are driven by an electric motor, which leads to improved flexibility in operations along with remote-controlled drilling. This method offers greater direct power to the drill bit by connecting the motor above the bit, below the hole.
