Fracture Diagnostic using DTS
New research paper publication with LSU
ISP in collaboration with LSU recently published a research paper in the Journal of Petroleum Science and Engineering.
Fracture diagnostic using distributed temperature measurements during a pause in flow-back period.
- A novel analytical solution is derived to model fluid temperature during shut-in after flow-back from single fracture.
- The temperature modeling results obtained are validated against those from a finite element model for multiple cases.
- Inversion characterizes inflow fluid temperature, surrounding temperature field, and after-flow velocity of each fracture.
- Contributions of this work through production logging diagnose the stimulation efficiency per fracture.
The significant temperature difference between the fractured and non-fractured regions during the stimulation
fluid flow-back period can be very useful for fracture diagnosis. The recent developments in downhole temperature
monitoring systems open new possibilities to detect these temperature variations to perform production
logging analyses. In this work, we derive a novel analytical solution to model the temperature signal associated
with the shut-in during flow-back and production periods. The temperature behavior can infer the efficiency of
each fracture. To obtain the analytical solution from an existing wellbore fluid energy balance equation, we use
the Method of Characteristics with the input of a relevant thermal boundary condition. The temperature
modeling results acquired from this analytical solution are validated against those from a finite element model
for multiple cases.
Compared to the warm-back effect in the non-fractured region after shut-in, a less significant heating effect is
observed in the fractured region because of the warmer fluid away from the perforation moving into the fracture
(after-flow). Detailed parametric analyses are conducted on after-flow velocity and its variation, flowing,
geothermal, and inflow temperature of each fracture, surrounding temperature field, and casing radius to
investigate their impacts on the wellbore fluid temperature modeling results.
The inversion procedures characterize each fracture considering the exponential distribution of temperature
based on the analytical solutions in fractured and non-fractured regions. Inflow fluid temperature, surrounding
temperature field, and after-flow velocity of each fracture can be estimated from the measured temperature data,
which present decent accuracie analyzing synthetic temperature signal. The estimations are independent on
each cluster, which can be combined to analyze the entire production section. The outputs of this work can
contribute to production logging, warm-back, and wellbore storage analyses to achieve successful fracture
Yilin Mao (ISP) | Mehdi Zeidouni (LSU) | Caroline Godefroy (ISP) | Michel Gysen (ISP)