+ What is the typical exploration and development programme for oil and gas?
We work with a step-by-step approach at all stages of shale gas exploration and development.
The first step in exploration is to review existing seismic and available data. Depending on how much information has already been gathered, we may need to plan an acquisition, processing and interpretation of new 2D or 3D seismic across the license area.
Seismic measurements are produced to locate oil and gas reservoirs by sending a pressure wave into the ground which is then reflected back when it meets a geological boundary, for example a boundary between sand and rock layers. Once the wave is reflected back, we are able to determine how far down the layers are beneath the surface. Technological advances have allowed seismic surveys to be undertaken in a matter of weeks, with only little to no disturbance to the land or local residents.
Assuming the seismic comes back with favorable data, the second stage of exploration begins which involves drilling 1-2 exploration wells. These are drilling in areas most likely to contain shale gas and are used to collect data on the composition of the gas and shale parameters (organic carbon, mature porosity, pressure/natural fractures etc). The wells are drilled over the course of 1 to 2 years.
If the exploration stage is successful, we will then more on to the development phase. This stage involves the drilling of three to five wells to determine if gas is present in suitable quantities and whether we are able to extract natural gas at commercial rates. This phase normally focuses on the area showing the highest potential as determined by the exploration phase. It may only cover an area of 10,000 acres or 40km².
The development phase may also involve a pilot production plant to service local energy requirements.
Subject to the development phase the production phase will commence. This involves the drilling of more wells at a frequency that will enable commercial gas to be collected and piped into a local gas hub. The production phase can take anywhere from five to twenty years.
+ How do you choose a drill site?
Drill sites are carefully chosen to take nature, community impact, geology, transport and future development into account. We adhere to best practice standards in choosing our drill site, which includes avoiding any NATURA 2000 lands or other EU sanctioned nature areas and setting up operations at a reasonable distance from any resident dwellings or towns. Community consultation is also very important to us and we do seek the advice of local representatives and citizens.
+ How many drilling rigs will there be?
During the exploration and development stages, it is likely that one drilling rig will be adequate. The rig will be on site for approximately four weeks for each horizontal well.
In production stage, the number will entirely depend on the viability, both economically and physically, of the area in question. However, one of the major benefits of shale gas exploration is horizontal drilling. This means that multiple wells can be drilled horizontally from the same drilling rig. With more subsurface activity, there is less impact on the surface.
A typical well-site is less than an acre in size and after the initial drilling and fracturing stages takes place (usually six to eight weeks), the well is reduced to a small well-head called a “Christmas tree.” This well-head can produce natural gas for decades, whilst the surrounding land is reconstituted to its original state.