TITLE PAGE. Report Title: Low Cost Methodologies to Analyze and Correct Abnormal Production Decline In Stripper Gas Wells

Transcription

1 TITLE PAGE Report Title: Low Cost Methodologies to Analyze and Correct Abnormal Production Decline In Stripper Gas Wells Type of Report: Quarterly Technical Report Reporting Period Start Date: 10/01/2000 Reporting Period End Date: 12/30/2000 Principal Authors: Jerry James, Gene Huck, and Tim Knobloch Date Report was issued: January 2001 DOE Award Number: DE-FG26-99FT40699 Name and Address of Submitting Organization: James Engineering, Inc. 231 Third Street Marietta, Ohio 45750

2 Disclaimer This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trade mark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

3 Abstract The goal of this research program is to develop and deliver a procedure guide of low cost methodologies to analyze and correct problems with stripper wells experiencing abnormal production declines. A study group of wells will provide data to determine the historic frequency of the problem of abnormal production declines in stripper gas wells and the historic frequency of the causes of the production problems. Once the most frequently occurring causes of the production problems are determined, data collection forms and decision trees will be designed to cost-effectively diagnose these problems and suggest corrective action. Finally, economic techniques to solve the most frequently occurring problems will be researched and implemented. These systematic methodologies and techniques will increase the efficiency of problem assessment and implementation of solutions for stripper gas wells. This fifth quarterly technical report describes the data reduction and methodology to develop diagnostic tools to evaluate the cause of declines in problem wells, specifically addressing the development of data gathering forms for tubing plunger wells, casing plunger wells, pumping wells, and swab or flow wells. This report also describes the methodology to select a group of wells for field review utilizing data gathering forms developed during this quarter.

4 Table of Contents List of Graphical Materials...1 Introduction...2 Executive Summary..3 Experimental. 4 Results and Discussion. 5 Conclusion References...12 Bibliography. 12 List of Acronyms and Abbreviations...12 Appendices...12

5 List of Graphical Materials Appendix 1 Appendix 2 Appendix 3 Appendix 4 Appendix 5 Appendix 6 J.V. Vogel s Inflow Performance Relationship Curve Triage Sheet for Abnormal Production Decline Review - Original Tubing Plunger Data Collection Form Casing Plunger Data Collection Form Pumping Unit Data Collection Form Swab or Flow Well Data Collection Form -1-

6 Introduction The goal of this research program is to develop and deliver a procedure guide of low cost methodologies to analyze and correct problems with stripper wells experiencing abnormal production declines. A study group of wells will provide data to determine the historic frequency of the problem of abnormal production declines in stripper gas wells and the historic frequency of the causes of the production problems. Once the most frequently occurring causes of the production problems are determined, data collection forms and decision trees will be designed to cost-effectively diagnose these problems and suggest corrective action. Finally, economic techniques to solve the most frequently occurring problems will be researched and implemented. These systematic methodologies and techniques will increase the efficiency of problem assessment and implementation of solutions for stripper gas wells. The following is the fifth quarterly technical report that addresses the data reduction and methodology for each of the following tasks: 1.) Develop Diagnostic Tools to Evaluate the Cause of Declines in Problem Wells, 2) Apply Methodology to a Group of Wells Where Recent Problems have Developed. -2-

7 Executive Summary The goal of this research program is to develop and deliver a procedure guide of lowcost methodologies to analyze and correct problems with stripper wells experiencing abnormal production declines. A study group of wells will provide data to determine the historic frequency of the problem of abnormal production declines in stripper gas wells and the historic frequency of the causes of the production problems. Once the most frequently occurring causes of the production problems are determined, data collection forms and decision trees will be designed to cost-effectively diagnose these problems and suggest corrective action. Finally, economic techniques to solve the most frequently occurring problems will be researched and implemented. These systematic methodologies and techniques will increase the efficiency of problem assessment and implementation of solutions for stripper gas wells. This fifth quarterly report describes results of the following two tasks: 1.) Develop Diagnostic Tools to Evaluate the Cause of Declines in Problem Wells, 2) Apply Methodology to a Group of Wells Where Recent Problems have Developed. Due to the tasks involved, we began this report with a brief review of the previous report of 01/01/ /31/2000 focusing on production responsibility, production reports, J.V. Vogel s Inflow Performance Relationship Curve, the statistical analysis of 376 wells, and the Triage Sheet for problem well review. During the development of the data collection forms for each artificial lift mechanism, we discovered that the data which was previously to be collected in the Triage Sheet was better suited for new data collection forms. While this not only eliminated duplication of information, it also made for a more meaningful review of information for analysis by all pertinent data now being on the new data collection form. A new Triage sheet will be developed to incorporate the data-collection forms. The data collection forms were divided into eight sections, three for field data collection and comment, and five sections for production manager analysis, recommendations, and comments. The forms provide for a logical review of data necessary for reviewing the cause of abnormal production decline. Finally, twenty-one wells of various artificial lift mechanisms were selected which recently experienced abnormal production decline. The results of the field review utilizing the data collection forms will be provided in the next quarterly technical report. In summary, the Triage Sheet provides a three-phase methodology for reviewing stripper gas wells with abnormal production decline while the data collection forms gather information required for the analysis of abnormal production decline. -3-

8 Experimental No experimental methods, materials, or equipment were used in this phase of the research. -4-

9 Results and Discussion This report addresses the following tasks: 1. Continued Development of Diagnostic Tools to Evaluate the Cause of Declines in Problem Wells. 2. Apply Methodology to a Group of Wells Where Recent Problems Have Developed Each task identified above will be reviewed in detail and describe the methodology utilized. Task 1 Develop Diagnostic Tools to Evaluate the Cause of Declines in Problem Wells Develop diagnostic forms of pertinent information to assist in the analysis of problem wells. Well equipment will be analyzed for mechanical failure. Shut-in and producing pressure information will be gathered to analyze bottom hole producing pressures. Fluid levels and other information will be collected to determine the effects of fluid on bottom hole pressure. Fluid production histories will be confirmed to determine what effect gas/liquid ratios have on stripper gas well performance. Pressure drops from producing formation to the gas sales point will be analyzed. Data Reduction and Methodology As discussed in the Quarterly Report for the period 01/01/ /31/2000, James Engineering, Inc. reported on the development of diagnostic tools to evaluate the cause of declines in problem wells. Problem wells were defined for the scope of this project as wells which exhibit abnormal production decline, i.e., greater than 50% departure from an established decline trend for more than three months. We begin this discussion with a brief review of the previous report of 01/01/ /31/2000 focusing on production responsibility, production reports, J.V. Vogel s Inflow Performance Relationship Curve, the statistical analysis of 376 wells, and the Triage Sheet for problem well review. The data collection forms developed during this quarter for each artificial lift mechanism will then be reviewed. Production Responsibility - The responsibility of achieving and maintaining well production from stripper gas wells fall to the production manager and the pumper. The very nature of stripper gas well production, specifically marginal gas well production, limits the amount of time and money available to maximize production. Through the consistent collection and analysis of data, the pumper can develop the skill and knowledge the skill and knowledge to keep many stripper wells which are close to the economic limit from becoming problem wells. The pumper has the ability to observe first hand the changes in well performance through changes he makes by observing pressure and production trends. -5-

10 Due to supervisory responsibilities, environmental, governmental, land duties, and budgetary restrictions, the production manager must spend as little time possible with the pumper assembling and analyzing the cause of abnormal declines in stripper gas wells. Production Reports - The three primary reports currently used by Artex Oil Company to assist in maintaining optimum production include weekly pumper reports, monthly gas production chart integration statements, and monthly Priority production monitoring reports. The gas chart integration volumes are reviewed, entered and tracked in a database and used to prepare production plots and Priority reports. The Priority reports quickly identify wells that do not meet forecasted values and allows the pumper to measure well performance to maintain optimum production volumes. The production manager and the pumper review the production reports at a weekly meeting where they discuss and resolve issues. J.V. Vogel s Inflow Performance Relationship - While there are a number of methods for determining a well s optimum productive potential, for the purpose of working with stripper gas wells James Engineering, Inc. begins with the premise that the productive potential of a well is inversely proportional to the ratio of the flowing bottom hole pressure to the shut in bottom hole pressure. We refer to the work completed by J. V. Vogel whereby Fluid flow in a reservoir is caused by movement of fluid from a high pressure area to a low pressure area and that fluid flow increases as the differential pressure increases. Vogel presents an Inflow Performance Relationship, or IPR curve for determining producing rate efficiency based upon the ratio of the well bore pressure to the reservoir pressure. Vogel s IPR is based upon the following formula: Q/Qm = *(Pfbh/Psibh) 0.8*(Pfbh/Psibh) 2 Where Q = Flow rate in mcfd at the current flowing bottom hole pressure. Qm = Maximum flow rate in mcfd at minimum flowing bottom hole pressure. Pfbh = Flowing Bottom Hole Pressure. Psibh = Shut in Bottom Hole Pressure. The Flowing Bottom hole pressure, or Pfbh, equals the summation of Pwh + Pgc + Poc + Pwc, where Pwh = Casing or tubing well head pressure Pgc = Pressure exerted by gas column Poc = Pressure exerted by oil column Pwc = Pressure exerted by water column -6-

11 A graphical representation of the IPR formula showing the relationship of the ratio Pfbh/Psibh to the percentage of the maximum producing rate, Q/Qm, is provided as Appendix 1. Note the graph indicates that approximately 90% of the reservoir s maximum flow rate will be achieved when the flowing bottom hole pressure is 25% of the shut-in reservoir pressure. Statistical Analysis - James Engineering, Inc. previously reported that through a 376 well review, ~72%, or 270 wells, were identified as having experienced abnormal production decline with the past five years. A statistical analysis of the 270 wells showed that fluid accumulation problems accounted for ~46%, gathering restrictions for ~23%, and mechanical failures for ~24%. Triage Sheet James Engineering, Inc developed a three-phase process to quickly and easily identify common production problems. The Triage Sheet, see Appendix 2, was developed to 1.) Identify the Problem Well, 2.) Measure the Problem, and 3.) Solve the Problem of the abnormal production decline. The overall philosophy of the triage form is to begin with the simplest analysis to eliminate the most common problems, and then to expand the analysis as necessary. Step one of Identifying the problem well provides a step wise process to not only review existing data ensuring the problem is with the well but also if the problem still exists. Step 2 of Measuring the problem was to review the data associated with bottom hole producing characteristics. The information requested in step 2 has now been included on the data collection form by artificial lift mechanism. Finally, step 3 of Solving the problem provides for an economic review depending on the recommendation of action required by the production manager. Data Collection Forms for Problem Well Analysis - Information previously requested in step 2 of the Triage Sheet have now been incorporated in the Data Collection Forms that will now be used in the field. The data collection forms focus on identifying factors that affect the flowing bottom hole pressure. The data collection form assumes a certain level of competence in the field personnel, which is critical for successful stripper well operations. Hopefully, the execution of the form will cause the pumpers to recognize and implement possible solutions at the field level. Well analysis forms, Appendix 3-6, were developed for the following four classifications of wells: Tubing plunger wells, Casing plunger wells, Pumping Unit wells, and Swabbing or Flowing wells. A separate sheet was developed due to the differences in information applicable to each artificial lift mechanism. The forms were divided into eight sections, three sections for field data collection and comment, five sections for production manager analysis and comments. These are detailed as follows: -7-

12 Section I: Field - Well Information requests general well information pertinent to the producing characteristics of the well to be completed by the pumper. This would include the producing formation(s), producing tubing pressure, producing casing pressure, artificial lift mechanism cycles, i.e., cycles per day, trips per week for tubing plungers, or unit speed and stroke length for pumping units, all information the pumper should know intimately. Previous producing characteristics as well as domestic gas usage, gathering system information, and fluid level information is also requested Section II: Field - Current Daily Production Rates requests the weekly and daily fluid production rates the pumper maintains in his records. Section III: Field - Comments and Recommendations allows the pumper to enter comments, additional data, and recommendations for the problem well based upon his first hand knowledge of the producing characteristics. Section IV: Analytical Data requests data input to quickly estimate the producing potential of the well. Typical data required is perforated interval, casing size, tubing size, depth of tubing, sales line size, sales line length, flowing bottom hole pressure, and last shut in pressure and date. Again the focus is to quickly evaluate the ratio of Flowing Bottom Hole Pressure to Shut In Bottom Hole Pressure. Section V: Vogel Chart Analysis requests data input to determine the impact of ratio of Flowing Bottom Hole Pressure, FBHP, to the Shut-In Bottom Hole Pressure. Using the calculated ratio and Vogel s Inflow Performance Relationship Curve, the percentage of maximum producing rate can be determined. Knowing the current producing rates and the maximum producing rate expected, the net production increase will determine the amount available to pay back any proposed work. Section VI: Forecasted Rates of Production contains the fluid production rates to be expected based upon the original production information and decline curve analysis. This establishes the base line for future production rates and is compared to the Vogel analysis for consistency. More detailed pressure information may be required if these rates do not agree. Section VII: Date and Description of Last Well Work will contain a brief description of the last well work completed. This will remind the production manager what has been done already and the results obtained. This is helpful when planning future well work or whether it is necessary to review a more complete history of the well work. Section VIII: Comments and Recommendations details how to proceed correcting the abnormal well decline based upon a review of all available data by the production manager. -8-

13 After this quick but thorough analysis of the well has been completed utilizing the data assimilated for the specific artificial lift mechanism, the production manager can the evaluate the best course of action, such as change the production cycles, the application of the existing artificial lift, or the gathering system pressure or line size. Finally, this analysis may also lead to a recommendation to sell or plug and abandon the well. -9-

14 Task 2 - Apply Methodology to a Group of Wells Where Recent Problems Have Developed From the study group, select a number of wells with recent abnormal declines. Evaluate the cause of the decline using the methodology and the diagnostic tools developed, and evaluate the potential for increase. Using the estimated cost, evaluate the group to select the most economical candidates. Remediation strategies may include equipment changes, well-bore clean-out, line pressure restriction reductions, and reservoir stimulation. Based upon the definition for abnormal well production, i.e., three months of consecutive production less than 50% of forecasted production, twenty-one wells were identified from decline curve analysis as having recent abnormal production declines. The following wells will be field reviewed utilizing the data collection forms to analyze the potential source of the abnormal well decline. Lease Name County Township Well Type 1. Aaron Woodford #1 Guernsey Washington TPL 2. Carrell #2 Noble Jackson TPL 3. Cross #2 Muskingum Highland TPL 4. Floda Dusky #1 Morgan Center PJW 5. Funk #1 Muskingum Highland TPL 6. Goff #1 Muskingum Union PJEM 7. Bernard Hall #1 Morgan Bristol PJW 8. Hoff #2 Washington Salem TPL 9. Huston #1 Tuscarawas Washington CPL 10. Jones #1 Coshocton Tuscarawas PJE 11. Kennedy #1 Guernsey Liberty CPL 12. Kuntz-Reed #2 Washington Aurelius TPL 13. Leachman #1 Muskingum Salem TPL 14. Lothes #2 Noble Jackson TPL 15. Marsh #1 Guernsey Liberty PJEM 16. R. McCall #1 Muskingum Highland TPL 17. Ellis Miller #1 Morgan Bristol PJW 18. F Mummey #1-A Morgan Bristol PJEM 19. Peterson #1 Guernsey Washington TPL 20. Shepherd #2 Guernsey Washington TPL 21. Mabel Wilson #1 Morgan Bristol PJW -10-

15 Conclusion The goal of this research program is to develop and deliver a procedure guide of low cost methodologies to analyze and correct problems with stripper wells experiencing abnormal production declines. This fifth quarterly technical report describes the data reduction and methodology to develop diagnostic tools to evaluate the cause of declines in problem wells, specifically data collection forms for the gathering of pertinent data for analyzing wells with abnormal production decline. Further, this report describes the data reduction and methodology to select a group of wells that have recently experienced abnormal production decline and to review with the recently developed data collection forms. The Triage sheet provides a three-phase methodology to identify the problem well, measure the problem, then solve the problem. The triage sheet focuses on the identification of factors that would affect the flowing bottom hole pressure. The overall philosophy of the triage sheet is to begin with the simplest analysis to eliminate the most common problems, and then expand the analysis as necessary. The data collection forms developed to measure the problem assimilate data to review and analyze abnormal production declines. In sections 1 3, the forms require field input and encourage comments and recommendations regarding the pumper s thoughts for correcting the problem well. Sections 4 8 of the data collection forms require the production manager to assimilate, analyze, then determine the course of action to correct the abnormal production decline. Overall, the triage sheet and the data collection forms provide for a consistent methodology to review, analyze, and correct abnormal production declines. -11-

16 References: Not applicable. Bibliography: Not applicable List of Acronyms and Abbreviations: Not applicable. Appendices: Appendix 1 Appendix 2 Appendix 3 Appendix 4 Appendix 5 Appendix 6 J.V. Vogel s Inflow Performance Relationship Curve Triage Sheet for Abnormal Production Decline Review - Original Tubing Plunger Data Collection Form Casing Plunger Data Collection Form Pumping Unit Data Collection Form Swab or Flow Well Data Collection Form -12-

17 Appendix Vogel's Inflow Perform ance Relationship Curve Bottom Hole Pressue Fraction of Reservoir Pressure % 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Producing Rate Percentage of Maximum

18 Appendix 2 Stripper Gas Well Abnormal Production Decline Triage Sheet Date of Analysis Lease Well ID Number Artificial Lift Mechanism / / Step Phase I: Identify the Problem Well Yes No If Yes 1. Identify Abnormal Production Decline from Priority Go to Step 2 2. Review Production Decline Curve and Forecast Go to Step 3 3. Check with Pumper to Verify Problem Still Exists Go to Step 4 4. Check for Metering Inaccuracy Go to Step 5 5. Check Integrity of Gas Gathering System Go to Step 6 Phase II: Measure the Problem 6. Check for Change in Sales Line Pressure Go to Step 7 7. Check for Change in Fluid Production Go to Step 8 8. Check for Flowing Bottom Hole Pressure Go to Step 9 9. Check Flow Performance Chart: Vogel IPR Curve Go to Step Is Well Producing at Optimum Production Rate? Yes,13: No, Is Well on Artificial Lift? Yes,16: No,12 Phase III: Solve the Problem 12. Go to Swabbing Sheet 13. Go to Compression Determination Sheet 14. Go to Artificial Lift Detail Sheet 15. Go to Artificial Lift Determination Sheet 16. Shut In for Bottom Hole Pressure Analysis 17. Review to Shut In to Sell or Plug and Abandon

19 Stripper Gas Well Data Collection Form for Problem Well Analysis Appendix 3 Lease Name and Well No: Date: / / Tubing Plunger, TPL I. Field Well Information IV. Analytical Data Producing Formation Perforated Interval(s) Tubing Pressure: Begin/End / Psi Casing Size In Casing Pressure: Begin/End / Psi Tubing Size In Tubing Plunger System style Depth of Tubing Ft Cycles per Day/Min On / Min Sales Line Size In Date Cycles Last Adjusted / / Sales Line Length Ft Previous Cycles per Day/ Min On / Min Flowing Bottom Hole Pressure(FBHP) Psi Domestic Gas Usage Yes / No Last Shut In date and Pressure(SIBHP) Psi Gas Gathering System Operating Psi Psi Additional Cycling in Gathering System V. Vogel Chart Analysis Ratio of FBHP/SIBHP Estimated Maximum Production Rate BOPD MCFD II. Field Current Daily Production Rate VI. Forecasted Rates of Production Oil, Bbl Oil per Week / Day BOPW/ BOPD Oil, Bbl Oil per Week / Day BOPW/ BOPD Gas, Mcf per Week / Day MCFW/ MCFD Gas, Mcf per Week / Day MCFW/ MCFD Water, Bbl Water per Week BWPW/ BWPD VII. Date and Description of Last Well Work III. Field Comments and Recommendations VIII. Comments and Recommendations

20 Stripper Gas Well Data Collection Form for Problem Well Analysis Appendix 4 Lease Name and Well No: Date: / / Casing Plunger, CPL IV. Field Well Information IV. Analytical Data Producing Formation Perforated Interval(s) Flowing Casing Pressure Psi Casing Size In Casing Plunger Style Flow Intermittent / Continuous Trips per Week Stand Depth Ft Cycles per Day / Min On / Min Sales Line Size In Domestic Gas Usage Yes / No Sales Line Length Ft Gas Gathering System Operating Psi Psi Flowing Bottom Hole Pressure(FBHP) Psi Additional Cycling in Gathering System Last Shut In date and Pressure(SIBHP) Psi Last Fluid Level Shot: Date/Depth / Ft V. Vogel Chart Analysis Ratio of FBHP/SIBHP Estimated Maximum Production Rate BOPD MCFD V. Field Current Daily Production Rate VI. Forecasted Rates of Production Oil, Bbl Oil per Week / Day BOPW/ BOPD Oil, Bbl Oil per Week / Day BOPW/ BOPD Gas, Mcf per Week / Day MCFW/ MCFD Gas, Mcf per Week / Day MCFW/ MCFD Water, Bbl Water per Week BWPW/ BWPD VII. Date and Description of Last Well Work VI. Field Comments and Recommendations VIII. Comments and Recommendations

21 Stripper Gas Well Data Collection Form for Problem Well Analysis Appendix 5 Lease Name and Well No: Date: / / Pumping Unit Well, PJEM or PJGE VII. Field Well Information IV. Analytical Data Prime Mover Perforated Interval(s) Producing Formation(s) Casing Size In Flowing Tubing Pressure Psi Tubing Size In Flowing Casing Pressure Psi Rod Size In Pump Schedule Pump Description Stroke Length In Depth of Tubing Ft Unit Speed SPM Sales Line Size Ft Date Cycles Last Adjusted / / Sales Line Length Ft Previous Cycles Flowing Bottom Hole Pressure (FBHP) Psi Domestic Gas Usage Yes / No Last Shut In date and Pressure (SIBHP) / Psi Gas Gathering System Operating Psi Psi Last Fluid Level Shot Date / Depth / Ft V. Vogel Chart Analysis Ratio of FBHP/SIBHP Estimated Maximum Production Rate BOPD MCFD BOPD MCFD VIII. Field Current Daily Production Rate VI. Forecasted Rates of Production Oil, Bbl Oil per Week / Day BOPW/ BOPD Oil, Bbl Oil per Week / Day BOPW/ BOPD Gas, Mcf per Week / Day MCFW/ MCFD Gas, Mcf per Week / Day MCFW/ MCFD Water, Bbl Water per Week BWPW/ BWPD VII. Date and Description of Last Well Work IX. Field Comments and Recommendations VIII. Comments and Recommendations

22 Stripper Gas Well Data Collection Form for Problem Well Analysis Appendix 6 Lease Name and Well No: Date: / / Swab Well, SWB or Flowing Well, FLW X. Field Well Information IV. Analytical Data Producing Formation Perforated Interval(s) Flowing Tubing Pressure Psi Casing Size In Flowing Casing Pressure Psi Tubing Size In Date Last Swabbed / / Depth of Tubing Ft Fluid Recovered Bbls Sales Line Size In Domestic Gas Usage Yes / No Sales Line Length Ft Gas Gathering System Operating Psi Psi Flowing Bottom Hole Pressure(FBHP) Psi Last Fluid Level shot Date / Depth / Ft Last Shut In date and Pressure(SIBHP) Psi V. Vogel Chart Analysis Ratio of FBHP/SIBHP Estimated Maximum Production Rate BOPD MCFD XI. Field Current Daily Production Rate VI. Forecasted Rates of Production Oil, Bbl Oil per Week / Day BOPW/ BOPD Oil, Bbl Oil per Week / Day BOPW/ BOPD Gas, Mcf per Week / Day MCFW/ MCFD Gas, Mcf per Week / Day MCFW/ MCFD Water, Bbl Water per Week BWPW/ BWPD VII. Date and Description of Last Well Work XII. Field Comments and Recommendations VIII. Comments and Recommendations