Geometrics DHA-7 Downhole Hydrophone Array

The Model DHA-7 downhole hydrophone array is designed for high-resolution seismic borehole imaging. The DHA-7 is suited for use in cased and uncased, water-filled, narrow-diameter boreholes, and is easily deployed by hand or with a small winch. With up to 24 channels in a single cable, the DHA-7 allows for fast and efficient high resolution downhole and crosshole data collection!

We manufacture the DHA-7 with unique proprietary polymer hydrophones (no ceramics) in-line molded into a fully integrated, triple-sealed multi-conductor cable. Non-shattering polymer material make possible superior performance and durability under the rigors of borehole applications and provide a stable signal response up to 10 kHz. Custom hydrophone group intervals (up to 5 meters) and multi-borehole configurations are available to tailor the system to meet your needs. The DHA-7 is terminated topside with a 61-socket connector to easily connect to our seismographs such as the Geode or ES-3000. All DHA-7 downhole hydrophone arrays are manufactured and assembled in the USA, and come with an industry leading warranty.

Features and benefits

• Adaptable: The DHA-7 is well suited for high-resolution downhole, VSP, and crosshole surveys
• Unmatched Engineering: State-of-the-art polymer hydrophones provide superior, stable response
• Impressive Noise Suppression: Unique design isolates vibration and suppresses cable-related noise
• Easily Portable: Small diameter cable and light weight per foot make for easy deployment in the field.
• Built Rugged: Reliably performs under the rigors of borehole applications; designed with the field in mind.
• Worldwide Distribution: No export license required!

TYPICAL USES

• Downhole and Crosshole Surveys: Ideal for shallow gas and mining investigations, imaging of faults and fractures, stratigraphy, voids, and underground structures. Accurately determine soil, rock and reservoir properties
• Engineering Applications: Foundation studies, earthquake engineering, and more.
• Research and Teaching: Easily connect to any 61 pin Seismograph like our Geode Exploration Seismograph. No expensive machinery required for deployment.

Technical Details

DHA-7 Hydrophone Specification List

ELECTRICAL

HYDROPHONE

• • Sensor type: Proprietary Polymer.
  • Sensors per group: One.
  • Frequency response: 10 Hz to 10,000 Hz ± 1.0 dB.
  • Capacitance: 5 nF at 22˚C.
  • Sensitivity: -197 dB re 1 Volt per 1 μPa.
  • Sensitivity with depth: < 1.0 dB over 400 m depth.
  • Sensitivity with acceleration: < -70 dB re 1 Volt per g.

PREAMPLIFIER

• • Type: Ultra-low noise differential.
  • Gain: 6 dB.
  • Current: 10 mA per channel.
  • Power: ±12V DC Model DHA Battery Pack on surface.

PHYSICAL

CABLE

• • Type: Multi-conductor with polyurethane jacket.
  • Termination
  • Topside: Y-type with one 61-socket connector (or 27-socket connector) and one 4-pin connector.
  • Tail: 1m (3.28ft) long with stainless steel swivel and 6 kg (13.2 lb) weight.
  • Maximum total length: 400 m (1,300 ft) (lead plus active section).
  • Strength member: Zylon center core.
  • Outside diameter: 13.5 mm (0.53 in).
  • Weight
  • 12 channels: 0.12 kg/m (0.08 lb/ft).
  • 24 channels: 0.15 kg/m (0.10 lb/ft).
  • Bend radius: 12.7 cm (5 in).
  • Working load: 273 kg (600 lb).
  • Breaking strength: 1,364 kg (3,000 lb).

ACTIVE SECTION

• • Channels: 12 or 24 standard; other counts available*.
  • Group Interval: 1 to 5 m (3 to 15 ft) standard; other intervals available with a minimum of 0.5 m (18 in)*.
  • Outside diameter (hydrophone): 41.3 mm (1.63 in).
  • Length (hydrophone): 30.5 cm (12 in).
  • Weight (hydrophone): 0.16 kg (0.35 lb).
  • Bend radius: 22.9 cm (9 in).

ENVIRONMENTAL

DEPTH

• • Operating maximum: 400 m (1,300 ft).

TEMPERATURE

• • Operating range: -10˚C to +70˚C (+14ºF to +158°F).
  • Storage range: -40˚C to +70˚C (-40˚F to + 158˚F).

DHA-7 Hydrophone Shipping Weights & DIMS

Downloads:

Geometrics DHA-7 Downhole Hydrophone Array Specifications

Geometrics DHA-7 Downhole Hydrophone Array Manual