In all geothermal projects the capital expenditure from drilling a doublet or group of wells form the most important challenge to the economic feasibility of the project. Enhanced Composite Casing Installation can not only greatly reduce the cost of drilling but also brings considerable reductions in operating expense and risk.
The main operating costs of a geothermal system are for electrical power consumption of the downhole pumps. These pumps need to overcome the friction losses in the closed system on both the production side as well as the injection side. Akiet High Strength Composite Tubulars have extremely smooth surfaces on both the inside and outside which can reduce the friction losses by 20% (compared to new steel) to 80% (on heavily corroded steel or surfaces with scaling).
The risks in operating a geothermal system are normally related to the geology and the chemical constitution of the water produced from the aquifer (reservoir). The water can contain a variety of ions that form acids or salts. The acids are the cause of corrosion and the salts can form scaling of a variety of unwanted types. Corrosion of steel tubulars can cause early abandonment of wells and there are examples of redox reactions in which solid metals (like lead) develop on the tubulars. These can not only clog up the well but can also contain radioactive isotopes with inherent radiation risks.
On steel tubulars precipitated salts can develop into crusts of scaling which will not only reduce the inner diameter of the tubular but which can also break loose in lumps which subsequently give problems in valves, pumps and the heat exchanger. Reduction of the inner diameter of steel tubulars increase friction, reduces flow and increases power consumption. Akiet composite tubulars remove the need for cathodic protection, scavenger or inhibitor sytems.
Akiet High Strength Composite Tubulars are highly resistant to corrosion and the smooth surfaces do not allow scaling to form. Operating costs and risks of increases in operating costs for power and workovers are virtually eliminated.