How We Operate
We develop onshore natural gas projects with a long-term view that measures success in multiple dimensions: economic, social and environmental.
We are part of the communities in which we operate, and work diligently to align our development with local needs. We consider each project independently, from the geology to the surrounding environment, and design our activities with innovative approaches that make sense for that area.
We place top priority on protecting the safety of our employees, the communities where we operate and the environment. Our strong safety record is built on strict company standards, multiple required safety barriers, and proven operating methods.
- Strict Standards - While all Shell onshore exploration and production operations comply with federal, state and provincial regulations, in many cases our design criteria and operating procedures exceed those standards. We believe our practices are among the most comprehensive in the industry. For every project, we develop a thorough “safety case” for each operation, making sure health, safety, security and environmental risks are identified and addressed.
- Multiple Barriers - To eliminate or greatly minimize design and operational risks, we add layers of safety by using a multiple-layer barrier system in our well and facility designs. In addition to physical barriers, we employ redundant systems to help prevent a problem from occurring, to monitor well conditions, and to respond and minimize the impact if a problem should occur.
- Proven Methods - Our operating methods combine decades of experience, state-of-the-art technology, and people expertise for maximum safety and efficiency. Shell drilling employees and contractors are trained in well safety and well control, and all personnel have the authority (and are expected) to stop any job they deem unsafe. In addition, every drilling rig has a safety professional with authority independent from the rig manager.
- Monitoring - Shell has redundant systems to closely monitor flow and pressures within the wellbore. In addition to onsite monitoring, we have operation command centers that give us the capability to observe aspects of our drilling operations remotely. Using sensors that are either on the drilling rig or placed in the well, Shell’s engineers and critical service providers can monitor a well’s real time operations, 24 hours a day, from any location with Internet capability. Our employees and contractors are extensively trained to review, detect and prevent or mitigate abnormal conditions if they should occur.
Life of an onshore well: finding and producing tight or shale oil and gas | Natural Gas
At Shell we believe natural gas is an important resource for energy future we also believe it must be produced safely and responsibly. Technology has made it possible to access gas and oil trapped in tiny spaces in Shale and sand formations deep under the earth. This short video explains how we explore drill and produce from a well.
We consider the geology and local environment to carefully select the well location. This might include gathering seismic data or information about air, wildlife or nearby water sources. We work with the regulators to plan the site. Then we begin by building the well pad for our operations.
During exploration, we may drill a single well or several wells to understand the gas or oil in an area. When we drill, we are careful to protect the surrounding area, including groundwater. We install multiple layers of steel pipe - also called casing - and cement around each layer of pipe. This is designed to isolate the gas and fluid in the well from the potable water table or drinkable water.
We typically drill several kilometers or more than a mile deep beneath the earth to reach the trapped hydrocarbon formation. Then to access gas or oil locked in shale rock, we drill horizontally. We may use different well designs depending on the local underground conditions. The entire drilling process can take several weeks or even months for each well drilled from the pad. Sensors in the drilling equipment feed us continuous data as we drill.
Once we reach the bottom of the well, we remove the drill and install steel pipe to the necessary depth based on our engineers’ design of the well. This typically takes only days with many safety checks along the way to be sure we have a good cement job and the well incasing and integrity are secure. This advanced drilling technology is one of the keys that make it possible to reach more the gas or oil trapped far below the surface within the shale or sand layer.
After the well is drilled, we remove the rig and prepare the well to begin the completions and hydraulic fracturing process. This is the second key to extracting gas or oil trapped in tights and shale rock. Hydraulic fracturing is a very carefully controlled process that releases the hydrocarbon from the tiny pockets in which it is trapped. We do not hydraulically fracture wells unless we have successfully pressure tested for wellbore integrity.
We lower tool called a perforating gun into the wellbore. We feed it down to the target location in the well. A well-log, which gives us data about the well, helps us know just where to position the tool. Once the perforating tool is in position, we fire carefully calibrated charges that perforate the well casing and connect the well to the tight sand or shale rock layer.
We inject a mix of fluids under pressure - mostly water with sand and chemicals to create fractures in the surrounding shale rock or tight sand layer. The sand pops open the cracks and allows the gas or oil to better flow into the well. When possible, we treat and reuse the fluid we recover during fracturing to minimize the amount of water we use. We support the release of information about chemicals used in fracturing fluids. We fracture the well in segments or stages.
After each stage, we put in a temporary plug to separate the fracture stages and prevent gas or oil from flowing too soon. The number of stages will depend on the local geology. We repeat this process until we have finished fracturing the length of the target area. Hydraulic fracturing and completing the well typically lasts only a few days for each well.
When we are ready, we drill out the plugs. This allows the gas or oil to flow into the well. At the well pad, the flow is separated into gas and liquids. The liquids might include oil or water that was also locked in the rock deep below ground. We collect the water to be reused, re-injected or disposed of according to local regulations.
The gas or oil continues to a pipeline to provide energy. During exploration, if no pipeline is nearby, we may need to temporarily flair or capture the gas in short-term facilities, or store the oil in short-term tanks on the location.
If we decide to develop the area, we typically put multiple wells on a single pad, reaching in different directions deep underground to minimize disturbance to the surface. All our wells and site operations meet government rules and our own rigorous standards for safety and protecting the environment.
Once drilling and completions are done, we remove most of our equipment, and reduce the size of the well pad. A well typically can produce needed energy for decades. We inspect and maintain well sites regularly during their productive life.
When the well is no longer producing, we comply with regulations to cement it closed, test that is sealed, remove all equipment and structures, and reclaim the site back into its surroundings. Permanent markers are installed to mark the well location.
Onshore Natural Gas Work Area
Shell requires a multiple-layer barrier system in its well designs, which greatly minimizes onshore drilling risks.
We choose the steel pipe (casing) for each well based on the specific characteristics of the formation. We use cement between each layer of casing; this holds the casing in place and prevents fluids or gas from flowing into the wellbore or between the pipe and the sides of the hole. Additionally, our wellheads have mechanical seals and locks to prevent gas or fluids from moving up the hole along the outside of the casing.
For high pressure, high temperature and all critical wells, including those in areas where natural gas contains higher levels of sulfur (“sour gas”), we go even further, creating additional barriers inside the well to protect it from erosion or corrosion caused by the chemistry of the sour gas. Our standards meet or exceed industry standards.
We always pressure test barriers within a well, including casing, wellhead and cement. If a pressure or integrity test does not meet Shell’s standards, we always stop and make the appropriate repairs in order to achieve strong barrier integrity. We do not hydraulically fracture wells unless wellbore integrity has been pressure tested and monitored.
The Blowout Preventer
It is Shell practice to go beyond regulatory requirements in terms of safety regarding blowout prevention.
The blowout preventer (BOP) is critical safety equipment featuring a configuration of redundant components, designed to secure a well in the event of loss of pressure control. It is vital that all components of the blowout preventer function as designed and intended – at that crucial moment. At Shell, BOPs undergo internal testing requirements in addition to the testing required by regulatory agencies. Should our testing indicate any abnormality in any part of the blowout preventer, drilling operations are suspended and the well is secured until the issue is corrected.
At each casing point (the point at which a section of steel pipe is cemented in the well), or after two weeks, Shell orders a function and pressure test on the BOP. Before drilling further beyond a casing point and beginning a new section, the BOP is again tested for integrity.
- Annular - Utilizes a donut-shaped rubber element to seal around a variety of pipe sizes to shut in the well when necessary, trapping pressure and wellbore fluids
- Pipe Ram - A high-pressure sealing device that closes around one or a range of pipe sizes to shut in the well
- Blind Ram - A sealing device that is used to shut in the well in the absence of pipe in the hole. It blankets the top of the well, trapping pressure and wellbore fluids
- Kill Line - If the drill pipe becomes inaccessible, drilling mud is pumped into the well here to re-establish well control
- Choke Line - When choking the manifold to reduce the pressure to atmospheric level, the pressurized fluid from the well will flow out of here
- Pipe Ram - (see above)
- Wellhead - Supports all casing and tubing in the well and connects to the blowout preventer
Safety Before We Drill
Before we even begin to drill a natural gas well, we use a set of practices, collectively called a “safety case,” that draws on our experience and expertise to identify and address the inherent risks in exploration and production. This industry best practice makes sure:
- Health, safety and environment issues are clearly identified and assessed
- Regulatory and Shell global requirements are met
- Risks have been removed or mitigated according to a structured, systematic Shell process, with any remaining risks demonstrated to be both tolerable and as low as reasonably practicable
- Critical safety items and procedures are identified to manage remaining risks
- A comprehensive environmental management plan has been developed
- Social, health, and environment benefits and opportunities are identified
- Personnel roles and responsibilities are indicated
Practicing What We Preach
Our facilities have been designed with the utmost safety in mind. As a further precaution, we conduct ongoing safety training in first aid, rescue, incident command, fire response and emergency response to make sure personnel on site are well prepared to protect both public safety and the environment
We run frequent internal safety drills, and also conduct community safety drills to help community first responders and others understand our safety procedures and communication processes. The following drills are performed depending on the area and requirements:
- ERP (Emergency Response Plan)
- MER (Medical Emergency Response)
- Rescue from Heights
- Well Control
- Abandon Location
- Spill Response
Fire response is integrated with the abandonment of location drills. Well control drills are simulated to time and test well control response. Hydrogen sulfide response drills are performed if needed to ensure safe evacuation of all personnel from the drilling site and surrounding area.