Notice of Retraction: Optimization of horizontal well length by streamline simulation

Summary Hot dry rocks (HDRs) exhibit wide distribution characteristics and have attracted considerable attention because of their considerable potential for geothermal development. A downhole coaxial heat exchanger geothermal system (DCHEGS) with a horizontal well is a novel and effective method for geothermal development and utilization from HDR. To examine the heat extraction performance, a mathematical model of a DCHEGS was established. This model was extremely accurate and consistent with the experimental test results (relative errors were <8%). By analyzing calculation results, we determined that the heat extraction power increased with the horizontal section length; however, the growth rate decreased. Hence, there must be an economical horizontal section length. Subsequently, to identify the optimal length of horizontal section, an economic evaluation model of a DCHEGS with a horizontal well based on net present value (NPV) was established. Finally, the economic evaluation model was applied using the GR1 Well as an example. The results demonstrated that the project can only be profitable when the horizontal section length of the GR1 Well is between 0 and 4009 m, and the optimal economic length is 1466 m. Thus, in this study, the horizontal well length design method proposed can effectively provide a theoretical support for the practical design and operation of DCHEGS.

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“…In Equations () and (), certain parameters can be expressed as follows: 35

C goodbreak= q_{m} c

C_{1} goodbreak= \frac{π}{4} d_{1 i}^{2} italicρc

C_{2} goodbreak= \frac{π}{4} ((), d_{2 i}^{2} goodbreak- d_{1 o}^{2}) italicρc

R_{1} goodbreak= \frac{1}{π d_{1 i} h_{1}} goodbreak+ \frac{1}{2 {πλ}_{p 1}} \ln ((), \frac{d_{1 o}}{d_{1 i}}) goodbreak+ \frac{1}{π d_{1 o} h_{2}}

R_{2} goodbreak= \frac{1}{π d_{2 i} h_{3}} goodbreak+ \frac{1}{2 {πλ}_{p 2}} \ln ((), \frac{d_{2 o}}{d_{2 i}}) goodbreak+ \frac{1}{2 {πλ}_{c}} \ln ((), \frac{d_{b}}{d_{2 o}}) goodbreak+ \frac{T_{D}}{2 {πλ}_{g}}

\begin{matrix} lefttrue \\ T_{D} = 1.1281 \sqrt{t_{D}} \cdot (1 - 0.3 \sqrt{t_{D}}) 10^{- 10} \leq t_{D} \leq 1.5 \\ T_{D} = (0.4063 + 0.5 \ln t_{D}) \cdot () \end{matrix}

…”

Section: Physical Problem and Mathematical Modelmentioning

confidence: 99%

“…The income of DCHEGS is the capital value of the heat absorbed by the working fluid from the formation, which can be determined using Equation (35):…”

Section: Incomesmentioning

confidence: 99%