Wellbore Temperature and Pressure Calculation of Offshore Gas Well Based on Gas–Liquid Separated Flow Model

Round 1

Reviewer 1 Report

·       Extensive english editing is required and you need to expand the full form of abbreviations like HPHT at the first instance of their mention in the manuscript, even though it is obvious that this is High pressure-High temperature.

·       Long sentences need to be cut short or split into 2 sentences for easier comprehension for the readers

·       Also improve on the literature review by citing papers such as “Predicting wellbore dynamics in a steam-assisted gravity drainage system: numeric and semi-analytic model and validation” and compare your work with those kind of works which are very similar to what you did and explain your value addition and the exact literature gap you addressed

·       Why does reducing the G:L ratio decrease the temperature but increase the pressure of the wellbore?

·       Please provide references for statements with facts such as line 44 in the introduction

·       The rest of your methods and figures are really well-written and legibly shown, which is excellently done.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

The authors of the article devoted a lot of work to creating a model process for calculating the heat transfer between seawater and the tidal stream extracted from the bottom of the borehole. The discussed topic of the temperature in the borehole is important, in particular, for the continuity of the flow. The extracted gas with water often forms hydrates during extraction, so it is important to know the temperature of the liquid at the head. The proposed model of calculating this temperature after validation reflects the real conditions well and the measurement error is small. I propose to accept the article for publication as is.

Author Response

Thank you for taking the precious time to review our paper during your busy schedule. Thank you for your recognition and support of our article. We will continue to work hard and do better in the future. And your comments and suggestions will greatly help the quality of the article.

Reviewer 3 Report

The manuscript reports an improved calculation model of wellbore temperature and pressure field for the offshore HPHT wells. Detailed studies of the influencing factors in offshore gas wells are presented providing the results that represent a notable advance for the rational formulation of the well production plan.

The title and abstract are appropriate for the content of the text. In abstract, the authors summarized the main research question and key findings. The description of study subject and results are detailed and correct. In Introduction, the authors provide a comprehensive summary of previous research and important publications related to this specific topic. Furthermore, the manuscript is well constructed and the calculation models are well performed. Data collected are interpreted accurately and the results support the conclusion. The manuscript reads well. The figures are clear and readable and support the findings.

Overall, this is a clear, concise, and well-written manuscript that has implications for theoretical basis, construction and wellbore safety assessment. In my opinion, the manuscript is suitable for publication in Processes in a present form.

Author Response

Thank you for taking the precious time to review our paper during your busy schedule. Thank you for your recognition and support of our article. We will continue to work hard and do better in the future. And your comments and suggestions will greatly help the quality of the article.

Reviewer 4 Report

Obtaining an accurate temperature and pressure field in the wellbore is very important in drilling technology. Therefore, in the article, the authors described the method of two-phase gas-liquid separation, where they developed an improved computational model of the temperature and pressure field in the wellbore for offshore HPHT wells. The characteristics of the heat exchange environment "formation, sea water and air" have been taken into account. A very small measurement error of only 0.87% and 2.46% was obtained.

The authors' improved computational model of wellbore temperature and pressure for two-phase flow is a very important aspect in the oil industry. The authors rightly conclude that forced convection heat exchange between seawater-air and the wellbore is stronger than between the wellbore and the formation, therefore the effect of seawater and air stretches on the temperature of the wells in offshore gas wells should be fully considered. The authors conclude that the improved model could provide a more accurate estimate of the time to nominal head temperature and accurate theoretical support for a rational formulation of a production plan after well opening, which is a very favorable conclusion.

The work is written very well, only the literature recognition can be increased by several items. But this remark does not detract from the quality of the work. I recommend for publication.

Author Response

Thank you for taking the precious time to review our paper during your busy schedule. Thank you for your recognition and support of our article. We will continue to work hard and do better in the future. And your comments and suggestions will greatly help the quality of the article.