GeochainSlim™ Well Seismic Instrumentation

The GeochainSlimTM is the next development of the field proven VSP and hydraulic fracture monitoring. This system has been designed for use in open or cased holes with all locking arms opening simultaneously to reduce survey time. A maximum bandwidth of 1600Hz, very low electronic noise levels and slim size make the system ideal for hydraulic fracture surveys.

The established extra high sensitivity GeochainTM Quad geophone sensor pack has now been integrated into the GSR design and is now available as a standard configuration. The GeochainSlimTM system also benefits from the new gapless recording functionality* which is ideal for the continuous requirements of passive monitoring.

ASL  X Series SLIM Brochure

DOWNLOAD Geochain Slim Datasheet

  • Ideal for VSP & Microseismic surveys
  • Up to 62 satellites
  • Slim 1 11/16” (43mm) Outside Diameter Tool
  • UPGRADED: Unique Active Cooling System for continuous operation at 385°F/195°C.
  • 20,000psi (1400 bar) pressure rating
  • Standard 7 conductor wireline with GO7 connection
  • Real time data transmission
  • Extra sensitive QUAD 3 component sensor
  • 24-bit delta sigma convertors
  • Up to 200m (>600’) between satellites
  • Operates with all standard ASL surface panels
  • Gapless recording for passive monitoring surveys
  • Tractor deployment capability

Geochain Slim GSRS

The GeochainSlim Receiver (GSR) innovative design packages all the functionality of the acclaimed ASR-1 receiver into a much slimmer housing.  The GSR tool is a compact three component electromechanical downhole geophone. It is designed for use in wells up to 20,000psi and 195oC (digital) 200oC (analogue) and provides a fast arm cycle time with an arm force to weight ratio of 5:1. It can be easily and quickly converted from an analogue system (up to two tools) to part of a multilevel digital GeochainSlimTM system.

The downhole distributed electronics features 24 bit Delta-Sigma converters along with switchable downhole gain for maximum dynamic range. Continuous PLL synchronisation to the surface clock allows for very long record lengths* with no timing skew.

Full in field processing is provided by our highly praised ACQ software suite and VSProwess (supplied with each system purchase) enables complex data processing to be performed at the rig site.

The GSR is a development of the well tried and tested ESR tool and has been designed so as to require very little servicing.  Routine maintenance can be performed in a few minutes and even a complete overhaul can be accomplished in less than an hour.

The GSR comes with a three component sensor pack as standard. The sensors are fixed Quad high sensitivity OMNI-2400 15Hz geophones which are suited to both VSP and fracture monitoring surveys. The sensor pack will work in any orientation from vertical through to horizontal.

An optional gamma ray tool or CCL can be used for depth correlation and line 7 (on hepta cable) is free for use with any third party tools that meet the single conductor power requirements.

A BRAND NEW  Slim TCU tension head and motion detector provide real time surface read out to prevent tool hang up is now available . 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.

The standard arm will accommodate boreholes from 1-7/8” to 7” and an extended arm can be used to increase this range to 13”. The locking force is constant to within 20% throughout its operating range and will lock into 3-1/2” drill pipe in fifteen seconds.  The arm mechanism has a failsafe feature to facilitate recovery of the tool in the event of downhole failure.

The tool can be used in single or dual tool analogue mode and can be combined with our Gamma Ray tool for depth correlation. The GSR receivers accommodate a modular construction 25’ rigid inter tool connector rated to 20,000 psi, 200oC. This low maintenance item provides precise tool alignment and can be coupled together to give a 50’ spacing.

In digital mode the tool can be combined to a maximum of 62 levels with 200m spacing between levels (all using standard seven conductor wireline throughout).

When used in digital mode, the GeochainSlimTM employs the STAS-1 Slim Telemetry Adapter Section and SVRS-1 Slim Voltage Regulator Section at the top and bottom of the tool string respectively.  The GSR-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 GeochainSlimTM 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 system can be modified to a low cost yet robust Analogue set up, for high temperature (200oC) surveys.

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

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.
GSR-1 GeochainSlimTM Receiver
GSR-1 Satellite Specifications  
Length 44” (1135mm)
Diameter 1 11/16” (43mm)
Weight 19.5lbs (8.85kg)
Max locking range 7” (178mm) Standard or 13” (330mm) with long arm
Max locking force 300 lbs (Standard Arm)
Temperature 400oF (204oC) Analogue, 385oF (195oC) Digital AS271 – (180oC pre 2016 electronics modules AS270).
Pressure 20,000psi (1400 bar)
Sensors 3 Component Fixed – SMC 2400 15Hz Omni Directional Geophone – 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 GSR’s (using SDFU)
  1/4ms 1600 8 (15)
  1/2ms 800 16 (30)
  1ms 400 32 (60)
  1.5ms 266 48 (80)
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 X-Gen Digitizer)
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 ( 0-50°C)
Enclosure Standard 19” rack mounting