Getting To Grips With The Oil Drilling Process

There are certain things we take for granted in life without ever stopping to wonder about how they actually work. Oil drilling is one such process. We just assume there to be fuel as and when we need it. We’d wager that few people have ever taken stock about how oil is welled, at least not in any kind of depth.

It’s an incredibly interesting and complex discipline, one which requires extensive skills and expertise distributed between a team of professionals working in separate areas. The team here at TriStone Holdings, a leading oil and gas venture capital firm in the UK, wanted to talk in more detail about the oil drilling process, so that you may better understand what goes into extracting the globe’s leading fuel (oil accounted for roughly 34% of the world’s total energy consumption back in 2018).

The Planning Stage

Like anything in life, preparation and planning are what make things tick. Charging gung-ho at a lease with no prior geological knowledge would yield far worse results than one in which adequate research has been undertaken as to the prospect’s viability. In the planning stage, a target is picked in order to optimise well production. This is then matched with an appropriate surface locus and a trajectory is drawn up between the two. Subsequently, engineers will create a set of assumptions regarding the subsurface. These include geological characteristics such as lithology, wellbore stability, permeability and many more. At this point, the drilling team themselves become involved, determining the necessary drilling fluids, drill bits and borehole casings that will be needed for the well. As you may be beginning to see, drilling an oil well is a complex and highly collaborative process. Fortunately, the team here at TriStone Holdings work with highly experienced professionals across all the requisite industries and disciplines, meaning we’re suitably well-placed to tackle the industry.

The Drilling Stage

When all the preparation has been put in place, then (and only then) can the drilling process itself begin. Drilling occurs using a rotating drill string with an attached drill bit. After having drilled the initial borehole (which can be up to one metre in diameter), casing (steel, often with additional cement) is used to add structural integrity to the borehole’s sides, helping to mitigate any risk of collapse. The well can then be drilled with incrementally smaller drill bits and casing sizes, downwards towards more unstable geological formations. Whilst the drilling is under way, drilling ‘fluid’ is pumped out of the drill bit and into the borehole; this is done to keep the drill bit cool and prevent potential destabilisation of the surrounding rock. All of this – the borehole progression, fluid circulation and cuttings removal – Is facilitated by the on-surface drilling rig.

The Completion Stage

Once the borehole has been drilled, the well must be ‘completed’. In most instances, this involves creating perforations in the casing so that oil can travel through into the wellbore. Fracturing fluids may then be used to further induce the hydrocarbons to enter the borehole. Whilst the subsurface pressure is often enough on its own to cause the oil to flow

to the surface, sometimes equipment such as pumping jacks are used to aid with the artificial lift of oil to the surface. This kind of equipment is particularly useful in horizontal wells where getting oil to the surface proves more naturally difficult.

The Production Stage

Once the oil has begun to flow, the production stage has been reached. At this stage, the drilling equipment and rig can be moved off from the borehole which will then instead be capped with a series of valves. These can be used to regulate flow and better control well pressure. The outlet valves of these contraptions (often referred to as Christmas Trees thanks to their distinctive appearance) usually links to a pipeline or tank. From there the oil can be transported to refineries or wherever else it’s happened to be needed. Obviously, a well is not an infinite source of oil and there will come a time when it begins to run dry. The point at which the well should be abandoned can be determined using complex calculations, far too advanced for this here blog! An abandoned well does not always signify the permanent end of a well’s usage, however. Sometimes they’re re-entered for production or, alternatively (and increasingly in today’s world) used for hydrocarbon storage. The extensive nature of an oil well’s life cycle, from planning to abandonment, shows just how comprehensive an understanding of the industry that oil and gas venture capital firms must possess in order to succeed. Here at TriStone Holdings, we possess that understanding.

Hopefully, after reading this, you’ll have developed a somewhat greater understanding of what is one of the world’s most commonplace, yet least understood, industrial activities. So, if you’d like to find out more about the oil drilling process, then get in touch! Contact TriStone Holdings today on 0800 055 7079.


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