INTRODUCTION TO GEOTHERMAL WELL LOGGING AND TESTING
Transcript of INTRODUCTION TO GEOTHERMAL WELL LOGGING AND TESTING
Sustainable Development Goals Short Course IV on Exploration and Development of Geothermal Resources
Felix Mwarania, Reservoir Engineer
INTRODUCTION TO GEOTHERMAL WELL LOGGING AND TESTING
23rd November, 2019
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
OUTLINE
• Introduction
• Well logging
• Conceptual models
• Well testing
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
GEOTHERMAL WELLS
Wells are vital in geothermal business. They provide;
• Access to energy extraction
• Information collection
Information from the wells is used in;
• Well siting
• Developing conceptual models
• As input for numerical models
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
WELL LOGGING
• Logging refers to continuous measurement carried out in boreholes
• The log shows changes in physical parameters measured as afunction of well depth
• The logs can be used to ‘estimate’ success of a well
• Parameters mostly logged in Olkaria geothermal field aretemperature and pressure
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
WELL LOGGING EQUIPMENT
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
WELL LOGGING – (COMPLETION TESTS AND HEAT-UP)
• Temperature and pressure logging • Pre injection Temperature/Pressure
• Injection tests• Multi-rate injection tests
• Injection Temperature/Pressure
• Pressure transient tests (pressure fall off)
• Temperature and pressure surveys• Conducted at regular intervals to monitor well recovery (1,4,7,14,21 and 28
days)
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
WELL LOGGING – TEMPERATURE PLOTS
Conductive profile:
• Observed in wells where rocks are impermeable
• Temperature increases linearly with depth
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
WELL LOGGING – TEMPERATURE PLOTS (2)
Convective profile:
• Depicts permeability in rocks
• Fluid motion controls temperature distribution.
• The profiles take a variety offorms, with isothermal sections,inversions, boiling sections or amixture
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
WELL LOGGING – PRESSURE PLOTS
• Injection profile Most useful in completion tests
• Gas pressure builds up when the well is shut and left to recover.
Gas rises until it is bled off or
Water level is depressed to theshallowest feed zone so that anyfurther gas is lost into theformation.
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
TEMPERATURE LOGS DURING INJECTION TESTS
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
TEMPERATURE PLOTS DURING INJECTION TESTS (2)
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
PRESSURE DURING INJECTION TESTS
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
TEMPERATURE CROSS-SECTION MAP
Temperature cross section – Eburru field
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
TEMPERATURE PLANAR MAPS - EBURRU
Temperature iso - map at 1000m a.s.lTemperature iso - map at 500m a.s.l
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
CONCEPTUAL MODEL - EBURRU
The information is used in developing conceptual model which explains;
• Heat source
• Upflow and outflow
• Recharge areas
From Eburru model
• Upflow is around EW-01
• Outflow at 1500 m a.s.l
• Cold recharge from all directions.
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
CONCEPTUAL MODEL - OLKARIA
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
CONCEPTUAL MODEL – OLKARIA (2)
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
WELL TESTING
Wells are monitored duringheat-up period by regular;
• water level or wellheadpressure measurement
• temperature recoverymeasurement
Once a well has heatedsufficiently, it is dischargetested to obtain informationon well productivity and fluidchemistry
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
METHODS TO STIMULATE FLOW IN WELLS
• Water level depression by pumping air using compressors
• Steam or two-phase injectionwhere a well is heated andpressurised using steam fromanother well
Because a well is difficult to start doesn’t mean that it is likely to be a poor producer.
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
WELL SET-UP IN KENYA
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
BRINE FLOW MEASUREMENT
• Common measuring methods• V-notch weir
𝑚 = 0.824 ∗ ℎ2.5∗ 𝜌
• Other methods• Timing
• Flow meters
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
STEAM FLOW MEASUREMENT
• Critical pressure measurement is common
• Uses Russel James formula
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019
WELL TESTING INFORMATION
Shows how well dischargeparameters change underdifferent throttle conditions.
Data used to plot characteristiccurves
SDG Short Course IV on Exploration and Development of Geothermal ResourcesOrganized by UNU-GTP and KenGen | Lake Bogoria and Lake Naivasha | Nov 14-4 Dec, 2019