Hydrophone housings in seismic surveys 

In the field of oil and gas exploration, seismic surveys are performed to locate and determine the size of oil and gas pockets. The most common technique used to determine possible deposits is using highly sensitive hydrophones. Hydrophone strings consist of thousands of linked individual hydrophones, encased in lubricant filled tubing. These hydrophones are used to record sound waves that are bounced off the ocean floor, which provide information on rock formations and possible deposits.

Requirements in harsh environments

Before any oil drilling can take place, possible oil wells must be located. On average, only about one in every ten wells are successful, making it imperative that the information recorded by the individual hydrophone is accurate. All aspects of the hydrophones must be highly reliable and unhindered by any faults to avoid misleading readings, reducing further costly exploration and minimizing the environmental impact. To ensure this, the individual hydrophones require housings to protect them from damage. Engineering materials such as metals, ceramics and plastics are typically used to construct the hydrophone housings. Key factors must be considered when choosing the material for this application, as the environment that it operates in poses a number of obstacles which could cause potential damage. Saltwater, sunlight and chemicals such as oils and lubricants used within the tubing can have an impact on the operation of the hydrophones, therefore good chemical resistance is paramount. Other factors such as impact resistance, dimensional stability and acoustic properties should also be considered.

Innovative solutions

Engineering thermoplastics are highly advantageous for these housings given the exceptional properties that they hold. Metals tend to be far heavier than plastics, therefore the use of plastics would be particularly beneficial on ships, where weight and ease of handling a lighter material is favored. Ceramics are usually more expensive than plastics, harder to machine and damage easily due to their brittleness.

Polycarbonate (TECANAT) is often used for this application given its high impact strength and its good resistance to external influences such as weathering and UV-radiation. However, if tougher requirements or chemical resistance are needed, other engineering plastics such as fluoropolymers (TECAFLON), poletherimide (TECAPEI) and acetal homopolymer (TECAFORM AD) may be more suitable. These plastics are particularly suited to this application due to their distinctive combination of chemical and impact resistance, high strength and dimensional stability and acoustic properties. Each of these thermoplastics hold properties that make them more favourable over the other. TECAFORM AD is commonly used due to its high mechanical strength and is easy to machine. TECAFLON may be preferred for its exceptional chemical resistance, whereas TECAPEI is lighter in weight which may be more suitable. Therefore, this application can benefit greatly from all three, however, the best material choice is dependent on the specific requirements/preferences.

Profit from saving costs and time 

The use of plastics can lead to longer part lifetime in comparison to brittle ceramics, thus, resulting in reduced maintenance, downtime due to damages or faulty readings, and replacements costs. In addition to this, these thermoplastics, in particular TECAFORM AD, have great machinability saving time and reducing costs.

Furthermore, Ensinger has a broad portfolio of thermoplastics ideal for this application, each holding properties to suit your special requirements. Alongside this, Ensinger's team of technical application engineers are on hand to advise you with material selection in order to provide the optimum solution for your application.

Materials of choice

TECANAT natural

Due to its low level of crystallinity, Ensinger's polycarbonate, marketed as TECANAT natural, has a high level of transparency. The unmodified PC is characterised...


POM-H is a homopolymer acetal that is manufactured by Ensinger under the tradename TECAFORM AD natural. This homopolymer acetal has exceptional sliding characteristics and good wear resistance properties.

TECAPEI natural

TECAPEI natural (PEI) has high mechanical strength and rigidity, very good hydrolysis resistance, dimensional stability and a relatively high long-term service temperature...


This unreinforced material is Ensinger's basic type of PVDF offering. It combines high density, high strength, and high chemical resistance, with very low moisture absorption...