Evaluation of Tiab`s Direct Synthesis (TDS) Drawdown Test in Comparison with Other Well Test Analysis Methods

Idris Musa Waziri, Gbenga Godwin Oseke, Shadrach Olise Ogiriki

Abstract


Pressure-transient analysis supports the estimation of reservoir permeability, apparent skin and wellbore storage, but uncertainty in identifying the infinite-acting radial-flow (IARF) interval may affect conventional semilog interpretation. This study compares Tiab’s Direct Synthesis (TDS) with conventional semilog analysis of a supplied pressure-drawdown dataset for an oil well described in the thesis as originating from the Niger Delta. The recorded flowing bottomhole pressures were analyzed using a production rate of 2,500 STB/day, reservoir thickness of 23 ft, oil viscosity of 0.92 cP and formation volume factor of 1.21 RB/STB. Pressure drop increased from 141 psi at 0.017 h to 3,021.2 psi at 21.6 h. The conventional method yielded permeability of 80.34 mD, apparent skin of 6.63 and skin-related pressure drop of 1,412.75 psi; TDS yielded 80.3782 mD, 6.64 and 1,410.92 psi, respectively. Both methods gave a reported flow efficiency of approximately 0.53. The permeability estimates differed by 0.0382 mD (approximately 0.0475%), indicating strong agreement rather than independently demonstrated superiority in absolute accuracy. The TDS logarithmic-pressure-derivative data exhibited an approximately horizontal plateau near 106.28 psi from 5.79 to 18.66 h, providing a clear observed IARF interval; analytical onset estimates of 2.16 and 4.13 h occurred earlier than this sustained plateau. The findings support TDS as a useful diagnostic complement to conventional analysis for identifying a defensible radial-flow fitting interval in the examined drawdown test.


Full Text:

PDF

References


Bourdet, D., Ayoub, J. A., & Pirard, Y. M. (1989). Use of pressure derivative in well-test interpretation. Verify full journal, volume, pages and DOI against the original publication before submission.

Onur, M., Yeh, N., & Reynolds, A. C. (1989). New applications of the pressure derivative in well-test analysis. SPE Formation Evaluation, 4(3), 429–437. https://doi.org/10.2118/16810-PA

Ramey, H. J. (1970). Short-time well test data interpretation in the presence of skin effect and wellbore storage. Journal of Petroleum Technology, 22, 97–106. https://doi.org/10.2118/2336-PA

Tiab, D. (1993). Analysis of pressure and pressure derivative without type-curve matching: 1—Skin and wellbore storage. SPE Formation Evaluation. Verify complete publication details and DOI before submission.

Escobar, F. H., et al. (2019). Pressure-transient/derivative-analysis source cited in the thesis. Verify exact title, author list, journal, pages and DOI before submission.

Dastkhan, Y., Kazemi, A., & Al-Maamari, R. S. (2022). Well and reservoir characterization using combined temperature and pressure transient analysis: A case study. Results in Engineering, 15, Article 100488. https://doi.org/10.1016/j.rineng.2022.100488

Kubota, L., & Gioria, R. dos S. (2022). Data-driven technique estimates skin factor and average pressure during oil-flowing periods. Journal of Petroleum Science and Engineering, 219, Article 111061. https://doi.org/10.1016/j.petrol.2022.111061

Malallah, A., Nashawi, I. S., & Algharaib, M. (2024). A comprehensive analysis of transient rate and rate derivative data of an oil well intercepted by infinite-conductivity hydraulic fracture in closed systems. Journal of Petroleum Exploration and Production Technology, 14, 805–822. https://doi.org/10.1007/s13202-023-01732-0

Kumar, A., Liang, L., & Ojha, K. (2024). Simultaneous inversion of permeability, skin and boundary from pressure transient test data in three-dimensional single well reservoir model. Petroleum Research, 9(2), 265–272. https://doi.org/10.1016/j.ptlrs.2024.01.004

Saleh, L., Traki, A., Alhaj, H., Gergab, M., & Al-Osta, M. (2025). Well test interpretation with TDS technique: Detection and absence of infinite acting radial flow, case study. Alqalam Journal of Science, 1(2), 207–216. https://doi.org/10.69667/ajs.25209.


Refbacks

  • There are currently no refbacks.