Hanny Oktori Hutabarat

EVALUASI PENGGUNAAN AERATED DRILLING PADA SUMUR “BHT” LAPANGAN PANAS BUMI

Introduction

Evaluasi penggunaan aerated drilling pada sumur “bht” lapangan panas bumi. Evaluasi penggunaan aerated drilling pada sumur panas bumi "BHT" yang mengalami hilang sirkulasi total. Optimasi laju alir lumpur-udara dengan metode GLRW untuk kondisi underbalance.

Abstract

AbstrakEvaluasi pemboran aerasi pada sumur directional “BHT” lapangan panas bumi yang mengalami kehilangan sirkulasi total (TLC) pada trayek 12,25” dengan kedalaman TLC 6387,5 ft MD. Diketahui dari data operasi pemboran bahwa laju alir lumpur-udara yang digunakan sebesar 800 gpm dan 1200 scfm dengan tekanan bawah sumur saat sirkulasi (BHCP) dan tekanan sumur saat berhenti sirkulasi (BHSP) yang dihasilkan sebesar 1798,90 psi, dan 1746,17 psi. Data tekanan fluida formasi yang didapatkan dari P&T survey sebesar 849 psi menandakan terjadi kondisi overbalance yang menyebabkan total lost circulation. Evaluasi yang digunakan dengan metode gas liquid rate window (GLRW) oleh Buyon Guo dan Ghalambor menghasilkan laju alir lumpur-udara yang optimum dengan menurunkan laju alir lumpur menjadi 380 gpm dan menaikkan laju injeksi udara menjadi 2200 scfm, menghasilkan BHCP dan BHSP sebesar 774,9 psi dan 674,75 psi, dan menyebabkan kondisi menjadi underbalance.Kata kunci: aerasi, underbalance, hilang sirkulasi, BHCP, BHSP. AbstractEvaluation of aerated drilling in “BHT” directional well, geothermal field that suffered total circulation loss (TLC) on 12.25"trajectory at depth of TLC 6387.5 ft MD. It is known from the drilling operation data that the gas-mud flow rate is used amounted to 800 gpm and 1200 SCFM with Bottom Hole Circulating Pressure (BHCP) is 1798.90 PSI and Bottom Hole Static Pressure (BHSP) is 1746.17 psi. The formation fluid pressure from the P&T survey is 849 psi signifies an physics condition that leads to total lost circulation. The evaluation used with the gas Liquid Rate window (GLRW) method by Buyon Guo and Ghalambor produce the optimum air-slurry flow rate by lowering the flow rate of mud to 380 gpm and raising the air injection rate to 2200 scfm, resulted in BHCP and BHSP amounted to 774.9 psi and 674.75 psi, and caused the condition to be underbalance.Keywords: aerated, underbalance,loss circulation, BHCP, BHSP

Review

This paper presents a timely and relevant evaluation of aerated drilling as a strategy to mitigate total lost circulation (TLC) in geothermal wells, specifically focusing on the "BHT" directional well. The authors effectively identify a critical operational issue – an overbalance condition leading to TLC in the 12.25" trajectory – by analyzing real-world drilling data, including operational flow rates and P&T survey results. The core of the study lies in applying the Gas Liquid Rate Window (GLRW) method, developed by Guo and Ghalambor, to optimize the mud and air injection rates. This approach aims to transition the wellbore environment from an overbalance to an underbalance state, thereby preventing or reducing the likelihood of future circulation losses. The abstract clearly outlines the problem and the proposed data-driven solution, indicating a practical contribution to geothermal drilling operations. A significant strength of this work is its direct applicability to a pervasive and costly challenge in geothermal drilling. By leveraging actual field data, the evaluation provides a realistic diagnosis of the overbalance condition that led to TLC. The application of the well-established GLRW method offers a systematic and scientifically grounded approach to parameter optimization. The abstract precisely details the proposed adjustments: a substantial reduction in mud flow from 800 gpm to 380 gpm and an increase in air injection from 1200 scfm to 2200 scfm. These specific recommendations, projected to achieve significantly lower bottom-hole pressures (774.9 psi BHCP and 674.75 psi BHSP) and an underbalance condition, represent a concrete and valuable output for field engineers facing similar lost circulation scenarios. While the abstract provides a strong foundation, the full paper would benefit from a more comprehensive discussion on the practical implementation challenges and potential limitations of the proposed optimization. For instance, exploring the operational feasibility of dynamically adjusting mud and air flow rates to the precise optimal values, considering equipment capabilities and wellbore stability, would enhance the study's practical impact. Furthermore, a deeper analysis of the sensitivity of the GLRW method's outputs to variations in formation properties or drilling fluid characteristics would strengthen the robustness of the findings. Despite these suggestions for expansion, this paper offers a commendable evaluation and a valuable methodological application to address a critical issue in geothermal drilling, laying a solid groundwork for improved operational efficiency and reduced non-productive time.

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