Hydraulic injection tests in the pilot EGS borehole PVGT-LT1 in Litoměřice, Czechia

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985891%3A_____%2F23%3A00576144" target="_blank" >RIV/67985891:_____/23:00576144 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/67985530:_____/23:00576144 RIV/00216208:11310/23:10475859 RIV/00025798:_____/23:10168920

Výsledek na webu

<a href="https://doi.org/10.1016/j.geothermics.2023.102805" target="_blank" >https://doi.org/10.1016/j.geothermics.2023.102805</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.geothermics.2023.102805" target="_blank" >10.1016/j.geothermics.2023.102805</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Hydraulic injection tests in the pilot EGS borehole PVGT-LT1 in Litoměřice, Czechia

Popis výsledku v původním jazyce

Successful utilization of geothermal energy is conditioned by sufficient permeability of the rock formation as a heat exchanger. We present results of hydraulic injection tests carried out in 2020 in the pilot geothermal borehole PVGT-LT1 in Litoměřice, Czech Republic, which samples 800 m of Paleozoic and Mesozoic sediments on the top of a crystalline basement. The low hydraulic conductivity on the order of 10−11 m/s obtained by recovery tests was verified by large-scale injection tests monitored by DTS temperature logging. During the first test, 24 m3 of water were injected and a permeable fracture was created at 880 m depth, breaking through the ignimbrite layer. The opening pressure of 12.55 MPa corresponds to the lower estimate of the minimum stress at this depth. The second injection was performed 7 months later and 202 m3 were injected at flow rates reaching 50 l/min. It showed that the fracture had been preserved since the first injection, which was documented by a non-zero flow rate at the smallest injection pressures and also by a stabilized water level in the borehole, which dropped immediately after the fracture formation. No induced seismicity accompanied the injection, which indicates a possibly low seismogenic potential of this area of the Bohemian Massif. The model of finite conductive fracture fitted to the pressure decay curve during shut-in intervals gives an estimate of a fracture half-length exceeding 100 m.

Název v anglickém jazyce

Hydraulic injection tests in the pilot EGS borehole PVGT-LT1 in Litoměřice, Czechia

Popis výsledku anglicky

Successful utilization of geothermal energy is conditioned by sufficient permeability of the rock formation as a heat exchanger. We present results of hydraulic injection tests carried out in 2020 in the pilot geothermal borehole PVGT-LT1 in Litoměřice, Czech Republic, which samples 800 m of Paleozoic and Mesozoic sediments on the top of a crystalline basement. The low hydraulic conductivity on the order of 10−11 m/s obtained by recovery tests was verified by large-scale injection tests monitored by DTS temperature logging. During the first test, 24 m3 of water were injected and a permeable fracture was created at 880 m depth, breaking through the ignimbrite layer. The opening pressure of 12.55 MPa corresponds to the lower estimate of the minimum stress at this depth. The second injection was performed 7 months later and 202 m3 were injected at flow rates reaching 50 l/min. It showed that the fracture had been preserved since the first injection, which was documented by a non-zero flow rate at the smallest injection pressures and also by a stabilized water level in the borehole, which dropped immediately after the fracture formation. No induced seismicity accompanied the injection, which indicates a possibly low seismogenic potential of this area of the Bohemian Massif. The model of finite conductive fracture fitted to the pressure decay curve during shut-in intervals gives an estimate of a fracture half-length exceeding 100 m.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10507 - Volcanology

Projekt

<a href="/cs/project/EF16_013%2F0001792" target="_blank" >EF16_013/0001792: Modernizace výzkumné infrastruktury RINGEN</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2023

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Geothermics

ISSN

0375-6505

e-ISSN

1879-3576

Svazek periodika

115

Číslo periodika v rámci svazku

DEC

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

12

Strana od-do

102805

Kód UT WoS článku

001076550400001

EID výsledku v databázi Scopus

2-s2.0-85168993645