GeochainTM EHP Extra High Pressure

Geochain EHP is one of the latest evolutionary branches of the established GeochainTM VSP digital seismic system.  It is capable of operating with up to 62 satellites for maximum logging and recording efficiency within the most hostile of high pressure environments.

The GeochainTM EHP system is fully compatible with all standard GeochainTM electronics and sensor modules in addition to all standard surface control panels.

DOWNLOAD Geochain EHP Datasheet




  • Ideal for VSP & Microseismic surveys in the most hostile wells
  • Up to 62 satellites
  • 3.25” (83mm) Outside Diameter Tool
  • Standard 7 conductor wireline
  • Real time data transmission
  • Multiple 3 component sensor options
  • 24-bit delta sigma converters
  • Unique Active Cooling System for continuous operation at 385°F (195°C)
  • 30,000psi (2100 bar) pressure rating
  • Up to 200m (>600’) between satellites
  • Gapless recording for passive monitoring surveys
  • Quick and easy conversion from Analogue to Digital operation
  • Tractor Deployment

The GeochainTM EHP array has been designed for use in the most harshest of open and cased holes using standard 7 conductor wireline.  The array is based on the well proven ASR-1 downhole geophone and can be used in wells up to 30,000 psi (2,070 bar) and hole sizes from 3 3⁄4”-22” (95 to 559mm).  The modular nature of the ASR-1 EHP tool allows quick optimisation for various surveys ranging from high temperature deep well check shot to complex high sensitivity microseismic monitoring.

All the satellites locking arms open and close simultaneously and the entire string can lock into a 9 5⁄8” (244mm) well in only 30 seconds.  All satellites have a failsafe arm mechanism for retrieval of the string in the event of power failure.  All Inter-Tool Cables (ITC) use standard 7 conductor wireline.  The cable heads have graduated weak links and composite pressure bulkhead connectors are used throughout.  A rigid ITC option is also available to preserve sensor orientation.

An optional TCU-2 tension head and motion detector provide real time surface read out to prevent tool hang up. A threshold alarm can be set to warn the wireline operator if tension or motion levels change. Full in-field processing is provided by our highly praised ACQ Software Suite featuring the latest VSProwess processing package.

Gamma Ray tool or CCL can be used for depth correlation and an auxiliary line is free for use with a downhole source or gyro tool and the system is tractor deployable for deviated wells.



When used in digital operation, the GeochainTM EHP employs the TAS-2 telemetry adapter section and VRS-1 Voltage regulator section at the top and bottom of the tool string respectively.  The ASR-1 downhole satellites are populated with the distributed electronic modules featuring 24 bit Delta-Sigma converters for maximum dynamic range along with real time data transmission and display. Constant synchronisation of the string allows for very long record lengths.

Our latest unique active cooling system (ACS) allows continuous operation up to 385°F (195°C) within a hermetically sealed environment, and the robust telemetry system will ensure operation in the harshest conditions.

Up to 62 satellites can be used in the array with a maximum tool spacing of >600 feet (200m).

Surface Control
The digital GeochainSlimTM system is supplied operating current at surface via a Geochain Power Panel (GPP) which features a Wireline Interface Box (WIB) enabling both DC power and AC data to be transmitted over same wireline cable. From 2016 this panel will be replaced by the upgraded Geochain Monitor Panel (GMP).  The entire system is controlled by a Geochain System Panel (GSP-1) which currently operates with a standard digital seismic interface and up to 16 analogue channels.  The panel has a 1.536Mb digital interface with 24 bit delta sigma converters along with a built in firing circuit. The GSP uses standard running ASL Acquisition suite.
Microseismic Mode
Digital GeochainTM systems can now be combined with a Downhole Formatting Unit (DFU) for passive monitoring operation to double the number of satellites in a string for a given sample rate.  These can record continuously/gapless at the highest sample rate for maximum picking accuracy and recording bandwidth.
Bypass Mode
The latest user friendly interface for the seismic engineer. The new ‘Bypass’ mode in the software enables data recovery from all active receivers, preventing any individual satellite failures from compromising the survey.  Any down tools can be bypassed, allowing communication and instruction to all tools below.
Mix & Match Operation
To help economize and maximize the output of your downhole itinerary, GeochainSlim Recievers (GSR) tools can now be deployed below Geochain ASR tools within the same string. 

The modular construction of the standard (analogue) ASR-1 EHP allows it to be easily converted to analogue operation in just minutes.  Replacement of the electronic module with a 200ᵒC rated downhole amplifier (DHA) enables a single or dual level string to be deployed within very hot wells.  The DHA and sensor pack can be upgraded to ASR-1 Extra High Temperature (EHT) to provide 225ᵒC operational temperature.

Surface Control
The analogue system is controlled by Geochain System Panel GSP-1 (currently operates up to 16 analogue channels) and a DCP-2 Dual control panel which allows operation of up to 2 analogue satellites.  The GSP uses standard running ASL Acquisition suite.

This mode of GeochainTM operation is ideal for very hostile well deployment such as deep check shot surveys. The requirement of only the ASR tool and no other telemetry/electronic devices (Gamma tools optional) allows the Geochain Analogue to be one of the most economic borehole seismic survey systems on the market.

Advanced Seismic Receiver (EHP)
ASR-1 (EHP) Satellite Specifications  
Length 35” (884mm)
Diameter 3.25” (83mm) without nodes
Weight 43.65lbs (19.8kg)
Max locking range 12” (305mm) Standard or 22” (559mm) with an arm extender
Max locking force 300 lbs (Standard Arm)
Temperature 400oF (204oC) Analogue, 385oF (195oC)  Digital (180oC when using older AS270/271/273 electronics modules).
Pressure 30,000psi (2100 bar)
Sensors 3 Component Gimbal – Sensor SM-4 HT 10Hz
  3 Component Fixed – SMC 2400 15Hz Omni- Dual/Quad
Well Deviation Control 0o-95o
Panels GPP/GMP & GSP-1 (Digital)
  DCP-2 & GSP-1 (Analogue)
 Coming Soon: GMP – (Replaces GPP – Provides Power with wireline QC and telemetry features).
System Specifications
Downhole Specifications  
Max. No. of Satellites 62
Telemetry Sample interval Bandwidth Hz Satellites (using DFU)
  1/4ms 1600 8 (15)
  1/2ms 800 16 (30)
  1ms 400 32 (50) Weight limit
Dynamic Range >112dB @ 0dB pre-gain (minimum)
A/D convertor 24 bit Delta-Sigma
Distortion <0.02%
DC offset Self-calibrating
Max. data rate
4Mbit/second using AS272 X Gen digitizer and DFU
Min. data rate 256kbit/second


Surface Specifications  
Recording panel GPP and GSP-1 (Digital) DCP-2 and GSP-1 (Analogue)
Software ASL Acquisition Suite and Copy of VSProwess© Processing Software
Cable equalisation Fully automatic using internal DSP chip
Down-going data rate 2 kbit/second
Airgun firing pulse 60 V, 30ms
Test system Fully automatic with comprehensive report generation
PC Interface USB
Power Requirements 100/230 V AC, 47-63 Hz universal input, 30 watts
Operating Temp 32-104°F (0-40°C)
Enclosure Standard 19” rack mounting