Exploiting smart well system for operation optimisation and field development cost minimisation
In recent years, the smart well system is creating a paradigm shift in the oil and gas industry, gradually revolutionizing well completion in the oil field.
According to the Intelligent Digital Oil and Gas Field, 2018 report, a smart well is a well that uses mechanical devices, which allow control of pressure and rates down-hole, to optimise production performance and ultimately improve oil recovery from the reservoir. The smart well design also incorporates digital downhole sensors that transmit data to surface throughout the lifespan of the well and helping the operator to make data-driven production decisions.
Smart well, also known as intelligent completion, comprises of having one wellbore to produce more than one zone, thereby reducing the cost of drilling and completing multiple wells.
The smart wells give the operators the functionality to control multiple wells zones remotely, without intervention using rigs, wire lines or coiled tubing.
Records have indicated that during the past ten years, production decline rates have doubled. At the same time as reservoirs get exploited, they become more complex and the reservoir model evolves. They are smaller, tighter, and more remote. As a result, reservoir recovery rates often decline over time to less than 35 percent.
The ultimate goal of many operators is to advance recovery rates to above 60 percent. The aggressive development of cutting-edge technologies has become essential, hence the emergence of intelligent completions.
In shallow waters where there are needs for production wellhead platforms, intelligent completion helps to maximise the use of the well slots on the production platform. This prevents building more expensive platforms while maximising oil recovery from the reservoir.
A fundamental type of equipment used in smart wells is a down-hole mechanical valve called an interval control valve (ICV) or Flow Control valve (FCV), which is present with orifices with different hole sizes. The ICV/FCV is operated either using an electronic pulse connected to an electrical cable embedded with a feed-through packer or hydraulically through a control line embedded in the completion from the wellhead, through a feed-through packer to the ICV. Another fundamental type of equipment used in the smart well is called the DownHole monitoring sensors, which often measure the pressure, temperature and flow at the zones thousand feet from the surface.
Smart wells combine a series of components that collect, transmit and analyse completion quality, production and reservoir data, control the inflow from the reservoir and provide selective zonal control to optimise the production process without operator intervention
Away from technical details, what has drawn close attention to smart wells adoption over the years is the Capital Expenditure (Capex) on oil field development coupled with the ease of handling the field tasks. The expensive cost and production loss during an intervention is another key factor driving the need for smart wells. For example, an intervention on a subsea well would require deploying a rig to the well site which could cost up to $1.2 million per day operating time for such rigs. Since smart wells offer an intelligent and data-driven approach to oil and gas extraction, this one unique structure in place would deliver the supposed objective of many conventional wells.
Smart well design and deployment come with some complexity as it is an integration of several completion technologies, solutions, remote-operated systems, and interfaces. There is a need for these integrated systems to have reliability for the lifetime of the well, which could be up to 35 years. The planning, design, engineering, and deployment are essential to the success of the well completion, avoiding non-productive time on the drilling and completion vessels.
However, experts have proffered that the adoption of project management methodologies would help to reduce the complexity in smart well implementation. Having project management in place helps simplify and modularise the planning, conceptualisation, design, preparation, and deployment of completion. Also, stressing that this applies to all environments from shallow waters to the ultra-deep-water situation.
It should be noted that while the smart well is the crux of the discussion, we cannot but put its economic implication as to the cynosure and compelling force behind its adoption.
The main objective of intelligent completion is to improve well productivity; by increasing contact with multiple reservoirs or zones and reducing the unit cost of drilling and production. The number of multilaterals well completions has risen substantially in the last several years due to advancements in directional drilling and completion systems. Smart completion also helps to integrate these multilaterals into one wellbore.
Initially, intelligent completion was used in deep water wells, where intervention is expensive and high-risked. Intelligent completions have since proven their value in managing production from multilateral wells, horizontal wells with multiple zones, wells in heterogeneous reservoirs, and mature tanks, and all these at relatively affordable costs.
Experts highlight smart well adoption to include reduction or elimination of extra wells, surface facilities, and intervention procedures; reduction in the water cut; as earlier mentioned. Moreover, smart well also reduces operational expenses (OPEX) by looking after for fewer wells, extends the life of wells and reserves, and cross-flow elimination and back allocation of commingled production for economic exploitation of marginal reserves.
A discussion on complete screening exercises or reviews by experts has proved to be the most convenient way to highlight the intelligent-completion value and intelligent completion’s ability to enhance asset value in terms of production acceleration, increased, ultimate recovery, and reduced operating expenditure (OPEX) and capital expenditure (CAPEX).
Further comparison between vertical, horizontal, and smart wells shows that the desired production target that could be achieved in a particular field would require 150 vertical or 66 horizontals well. However, this would require the deployment of only 48 smart wells in the same field to meet the same goal. In monetary terms, it is cheaper to drill and complete one smart well than what is required to drill and complete two or three vertical or horizontal wells.
Olusegun George Abolarin