ad

近道はない: 地熱貯留層からより多くの熱を取り出すための新たなアプローチ(No shortcuts: New approach may help extract more heat from geothermal reservoirs)

ad

2023-09-19 ペンシルベニア州立大学(PennState)

A rock outcrop with complicated facture networks

To produce more efficient geothermal systems, researchers have proposed a process called the fracture conductivity tuning technique. This approach involves preventing cold water and allowing hot water to flow through fractures — like the ones pictured here — in rock deep underground.  Credit: Provided by Arash Dahi Taleghani. All Rights Reserved.

◆地熱エネルギーはほぼゼロの排出物を持つ再生可能エネルギー源でありながら、発電の相対的に高いコストが課題でした。しかし、ペンシルバニア州立大学の科学者たちは、地熱発電所の運転停止を引き起こす「ショートサーキット」を防ぐ新しい技術を提案し、地熱発電の効率向上の可能性を示唆しました。

◆この技術は、地下の岩層に物質や化学物質を添加し、岩の内部から流れを調整するもので、効率向上と早期の冷水流入の防止が期待されます。モデリングによれば、この技術により50年間の地熱発電で熱抽出が65%以上増加する可能性があり、再生可能エネルギーを他のエネルギー源と競争力のあるものにする可能性があります。

<関連情報>

地熱発電の高効率化に向けた自律的な破砕流のチューニング Autonomous fracture flow tunning to enhance efficiency of fractured geothermal systems

Qitao Zhang, Arash Dahi Taleghani

Energy  Available online: 22 June 2023

DOI:https://doi.org/10.1016/j.energy.2023.128163

Abstract

To avoid any shortcuts that may “short-circuit” the fluid flow between the injection and production wells in an enhanced geothermal system (EGS), we explore the idea of autonomous in-situ tunning of fracture hydraulic conductivity (FCTT) and its potential benefits. The new technique is expected to provide variable fracture hydraulic conductivity depending on the surrounding temperature. Through FCTT, we can effectively manage the fluid flow in the reservoir and promote a uniform thermal gradient along the flow paths. A numerical finite element model is established to assess the impact of tunning magnitude and fracture network geometries on the production efficiency of EGSs. Results show that utilizing this technique could prevent an early appearance of fluid flow shortcut between injector and producer in an EGS. After 50 years of production, the output thermal power with the technique could be increased by 67.51%. Furthermore, we found that fracture density and fracture network connectivity in the reservoir could affect performance improvement reached by FCTT in production. We also present a field case with a realistic fracture network. After 50 years of production, applying this technique increases heat extraction by 101.78% in fracture networks that are expected in EGS. Since other flow-control systems in geothermal production are mainly focused on the wellbore and near-wellbore areas, this technique can provide a more effective enhancement in heat extraction by controlling flow deep inside the reservoir.

ad
0800資源工学一般
ad
ad


Follow
ad
ad
タイトルとURLをコピーしました