Optimization of the Well Start-Up Procedure and Operating Parameters for ESP Gas Well Dewatering

Round 1

Reviewer 1 Report (Previous Reviewer 3)

The revised paper is easier to read and understand than the previous one.

Author Response

Thank you for your constructive comments on our manuscript, and it's a great honor for us to get your acceptance.

Reviewer 2 Report (Previous Reviewer 2)

This paper proposes the optimization method for the well start-up procedure for the Electrical Submersible Pump well with the check valve to solve the start-up failure problem. The corresponding operating parameters are optimized to achieve the inflow and outflow balance. The pump efficiency is maximized based on the optimal production rate and operating frequency. The paper is reasonably organized, nevertheless, at this state, the paper is not ready for acceptance. The novelty of this study is not described clearly. The editorial support is needed to fix and spell-check the text in general, given that some grammar mistakes and awkward sentences preventing a proper understanding of the content have been found.

Author Response

Thank you for your comments on our manuscript. Those comments are valuable for improving our manuscript, as well as the important guiding significance to our research. The main corrections in the paper and the responses to your comments are as following:

Point 1：The novelty of this study is not described clearly.

Response 1：Thank you for your advice, we have detailed the novelty of this study in the Introduction part in this version of manuscript:

Original Version

None

Current Version

During the production in the D18 gas reservoir, two main problems are the failure to start up the ESP, and changes in reservoir parameters. For the first problem, the existing well start-up procedures and operation records were analyzed, and the results indicate the reason that a section of the gas column is sealed in the centrifugal pump below the check valve, thus leading to the ESP’s gas locking. The pump cannot provide sufficient head to open the check valve. To solve this problem, conventional solutions are pulling out the system, running a new system without a check valve, adjusting the position of the check valve upward, or just using an automatic reversing valve [14, 16, 17]. All of these conventional methods require costly workover operations. However in this case, a novel method was proposed, which could bleed the gas column trapped in the pump by alternately bleeding off the pressure in tubing and TCA (Tubing-Casing-Annulus). This novel method can solve the problem without any workovers, and save the costs, manpower, and time for the operators. For the second problem, the nodal analysis method was introduced to solve the problem. After months of production, one ESP system was pulled out and hydraulic fracturing was carried out for this well to enhance the production capacity. The original ESP system was planned to be installed for this well. Because the production capacity changed significantly, the operating parameters should be optimized. Traditionally, the ESP operating parameters were designed based on the water production rate. However in this case, the liquid production rate and the ESP operating frequency were designed simultaneously using the given ESP performance data to maximize the pump efficiency.

 

Point 2：The editorial support is needed to fix and spell-check the text in general, given that some grammar mistakes and awkward sentences preventing a proper understanding of the content have been found.

Response 2：Thank you for your advice, we have re-edited our manuscript with the help of an English native speaker. We hope that the new version could be easier to read.  The English Editing Certificate has been attached in the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report (Previous Reviewer 1)

The manuscript has been well strengthened at this round. I would recommend accept in present form.

Author Response

Thank you for your constructive comments on our manuscript, and it's a great honor for us to get your acceptance.

Round 2

Reviewer 2 Report (Previous Reviewer 2)

It's better to revise the manuscript exactly according to the comments.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The authors have revised the manuscript extensively and the quality has been greatly improved. I thus recommend accept of the article for publish. 

Reviewer 2 Report

This paper proposes an optimization method for the well start-up procedure for the ESP well with a check valve and the corresponding parameters are optimized. The overall structure and logical development are appropriate. However, the content of the manuscript is not novelty in my opinion. The editorial support is needed to fix and spell-check the text in general, given that some grammar mistakes and awkward sentences preventing a proper understanding of the content have been found. Many conclusions are known to readers. The authors may submit the manuscript to another journal.

Reviewer 3 Report

In this paper, the authors described that how the original ESP system was optimized. The results are interested for engineers and researchers in the field.