A Practical Method for EvaluatingRig Performance Bahram A. Sheikholeslami, SPE, Amoco Production Co. James D. Miller, SPE, Amoco Production CO. R.E. Strong, SPE, Amoco Production Co. Summary This paper introduces a practical method of calculating time required to perform the component drilling opera- rig efficiency incorporating both mechanical perfor- tions directly controlled by the rig and crew is used as a mance and the performance of the contractor's person- basis for evaluating overall rig performance. Rig effi- nel. By developing a concept called "contractor- ciency is then a function of both the rig and rig crew's controlled time" (CCT), the effect of the rig crew on mechanical and operational ability _ The theory implies various drilling operations can be included in the effi- that any rig should be able to equal the optimal or fastest ciency calculation. Several example calculations of rig time-if a particular rig is as efficient-both mechanical- efficiency involving actual field data are presented. This ly and operationally_ paper also addresses the effective cost of a rig to the Drilling a well involves many individual operations in- operator based on efficiency and the normal fixed costs fluenced by the contractor, the operator, and outside of the drilling operation. This new approach to rig effi- sources. This paper identifies the operations directly ciency can be applied to development drilling areas, with controlled by only the rig and rig crew. The time re- some limited application elsewhere. The results of this quired to perform these operations is defined as "total study have provided a means of comparing rigs and contractor-controlled time" (TCCT) (see Relationship 1, determining which is the most efficient and cost effec- Appendix A). Appendix B lists the contractor-controlled tive. The results also can pinpoint those operations categories used in this study and defines them as they where a particular rig is inefficient. This information relate to CCT. Routine operations such as rigging up and provides a method of evaluating rigs on a uniform and down, nippling up and down, cutting drilling line, and consistent basis. lubricating and repairing the rig are controlled directly by the rig's design and condition, and the crew's ex- Introduction perience and ability. Drilling, trip, and connection time have also been considered in this study as CCT. The concept of drilling rig efficiency has historically As a basis for comparison, rigs were selected from been associated with a rig's mechanical capability. various drilling areas (Fig. 1), with total depth and Generally a rig's size, mechanical condition, horsepower geology essentially the same for each well. This rating, and maximum load have been considered by equalizes drilling, trip, and connection time between many as determining efficiency. This concept of effi- wells. Additionally, these drilling areas were standard- ciency has ignored the rig crew and their ability to per- ized such that the drilling program was the same for each form routine drilling operations. well. Drilling parameters such as hole configuration, bit This paper describes a new method of evaluating drill- type, weight on bit, and rotary speed are therefore essen- ing rig efficiency incorporating performance of the con- tially identical. This normalizes operator and outside in- tractor's personnel and mechanical capability of the rig. fluence on the drilling, trip, and connection time. Efficiency is calculated on the basis of the time it takes a Following these basic assumptions, drilling, trip, and rig to perform various drilling operations. An inefficient connection time becomes a function of the rig and rig rig costs the operator or contractor both time and money. crew's ability to carry out the drilling program. This paper also presents a method to calculate daily rig It is important to note that any CCT associated with cost based on efficiency. Equations for rig efficiency and adjusted daily rig cost are included with a comparison of trouble or nonroutine drilling operations is not included in the TCCT relationship. It is recognized that TCCT is rig efficiencies. not limited to the categories listed in Appendix B. The concepts and equations discussed in this paper However, for the sake of uniformity and to provide a fair provide a practical method for both operator and contrac- comparison, nonroutine operations have been ignored in tor to evaluate and compare drilling rigs. our analysis. After the concept of CCT had been developed, an op- Theory timal or 100% level of rig performance had to be defined A complete evaluation of drilling rig efficiency should to allow calculation of rig efficiency. The "optimal include the effect of contractor personnel on the overall contractor-controlled time" (OCCT), Relationship 2, is drilling operation. To account for rig crew influence, the defined as the sum of the fastest time achieved by any rig 0149-2136/84/0031-1364$00.25 for each contractor-controlled category. Therefore, each Copyright 1984 Society of Petroleum Engineers of AIME drilling area has its own OCCT. When greater efficiency MARCH 1984 489 25 1.50 106.50 2.75 0 29. Rig 1 2~.00 497.OO 5.50 8.75 8.00 125.50 200.75 16.00 595.75 5.00 3.00 14.00 366.00 5.00 Contractor H.00 5.00 162.3.!iQ 2.25 7.25 6.50 0 10.25 East Texas-Field C Contractor A.50 0 10.75 8. Rig 1 47. Rig 1 32.00 2.00 399.00 4. Rig 1 3JJlO 39~QQ 2.00 399.50 100. Fig. Soutbern Fa'r.75 19.50 2.50 2.50 11.25 Contractor E.00 49.75 5.00 2.50 0 16.00 Contractor F.00 Contractor B.00 652.00 2.50 12.75 South Michigan Contractor H.25 104.00 2.00 1.50 OCCT 38.50 4.50 4.25 33.50 0 19.00 East Texas-Field B Contractor D.75 99. Rig 1 3JLOP' !i7Q&Q 3.25 1.50 3.50 3.00 4.00 OCCT 19.25 2.25 8.00 5.75 Optimal operating time for field 31.00 5.50 0 7.00 7.25 2.25 6.50 0 15.50 0 18.<~§Q 0 0 5.00 8. Rig 2 39.75 9.00 100.50 20.50 0 7.50 57.00 OCCT 31.00 162.00 6.50 2. Rig 1 39.50 North Michigan Contractor G.50 8.25 13.50 2.50 2.00 92.50 16.50 0 37.00 • Underlined numbers indicate optimal time 490 JOURNAL OF PETROLEUM TECHNOLOGY .00 16. Rig 4 l2&0 t. TABLE 1-TIME DISTRIBUTION (hours) Condition Rig Up! and Cut Tear Circulating Lubricating Repair Drilling Deviation Down Drilling Reaming Coring Mud Trip Rig Rig Line Survey Logs ------- East Texas-Field A Contractor A.JlP 162~5 0 0 5.50 0 0 8.50 4.50 1.00 697.50 4.75 1.25 7.00 21.50 10.50 3.00 OCCT 29.00 23. Rig 3 33.50 369. Rig 1 50.a.75 OCCT 24.25 5.00 35.50 Contractor E.00 Contractor D.00 11.1? 1.00 Q§.75 7.00 7.75 8.75 8.75 14.00 4. Rig 1 33.50 0 0 5.75 14. Rig 1 41.00 6.25 Contractor G.50 3.00 78.00 114.50 15.00 12.00 68.00 204.00 125.00 8.50 18.50 7.00 5.75 16.00 30.00 34.00 0 9.75 1.0Q 2.00 4.75 29.75 2.25 5.00 Contractor H.6§.00 8.25 6.75 29.00 34. Rig 1 50.25 28.00 3.00 9.50 3.50 3.50 8.50 60.00 3. Rig 1 41.50 57.50 3.00 8.00 474.75 1.25 1.75 7.00 19.00 Contractor B.00 Optimal operating time for field 24.00 Contractor H.75 6.50 0 19.50 2.00 15.00 366.00 3.50 57. 1-Location of fields.00 570.00 19.50 35.00 186.00 Optimal operating time for field 38.00 Optimal operating time for field 29.75 6.00 6.00 2.50 3.00 3.00 223.00 2.75 1.50 0 16.00 Optimal operating time for field 19.00 3.75 17.00 68. Rig 2 2~JlP :.50 0 18.25 27.75 33.00 Contractor C.25 17.25 152.00 4.00 3.75 0 0 5.00 81.00 429.50 7.00 ~.50 2.00 570. Rig 2 43.50 0.75 6.00 1.00 81.50 0 15.00 81.25 34.25 7.50 0 38.00 5.50 9.25 21.00 7. 00 5.50 10.75 1.25 3.00 12.50 19.----- 24.00 6. in each contractor-controlled category.50 0 0 0 0 0 10.00 0 0 0 0 0 10.75 67.00 632.----.00 7.75 25.75 9.50 8.00 1000 7.50 24.00 10.00 0 0 0 0 0 28.50 0 0 0 0 0 31.00 0 0 0 0 0 19.50 25. laying down OCCT is changed to reflect the new optimal perfor.30 19.50 567..00 0 0 0 0 0 10. one rig is operating inefficiently in each drilling area studied. Although none In the eatly development of our theory it became ap.25 900. This method of calculating rig efficiency provides drilling area.50 25. This "effective dai- tractors reports for a single well in each field. The OCCT for each drilling area may seem unattainable by a particular rig.00 736.00 27.50 16. Poor performance in any category can be identified and hopefully improved through discussion with the rig personnel while the well Effective Daily Rig Cost.00 0 0 0 0 0 16.134.50 13. a comparison could be made between cies calculated in Table 2 are based on past performance rigs regardless of the efficiency obtained in a particular and can be used to predict future performance in each field.25 882.25 40.00 14.25 12.00 14.00 8.50 18.25 962.75 18.00 16.50 17.50 0 0 0 0 0 29.25 10. calculated by use of Relationship 4.00 22. blowout preventer (BOP) drills. .75 8. is achieved for any contractor-controlled category.50 0 0 0 0 0 32.00 470.00 7.25 22.50 23.00 674.25 9.25 84.50 18.00 230.50 7. of Drilling Con.00 29. cleaning mud tanks.00 582.25 5.75 0 0 0 50. Assn.25 62.00 307.75 580.00 37.50 548.00 6.50 3.50 24.25 13.00 25. but if one rig is shown in Table 1 as the sum of the underlined values has achieved the optimal time.50 834.75 645.25 20.50 0 0 0 0 25.50 892.25 480.50 14.00 16.75 31.50 13.161.50 6.00 12.00 0 0 0 0 16.50 8.00 259. of the rigs studied operated at 100% efficiency.75 317.25 12. the ing soft line.00 9.25 424.00 690. mance level.50 0 0 0 0 0 25. each rig studied is calculated in Table 2.50 0 0 0 0 0 32.25 835.00 0 0 0 0 0 24.00 8.50 9. pump.25 14.50 0 0 0 0 0 27.00 573.50 0 0 0 0 0 30.75 31.75 25.00 705.00 0 0 0 0 0 19.00 16. Rig efficiency for ciency should be able to duplicate this time.00 9. The OCCT the TCCT for each rig.00 11.50 9.00 1. The time distribution was ob.00 11.50 13.----.00 14. drillpipe and collars.00 24.25 22. and Rig efficiency is calculated by use of Relationship 3 as changing bottomhole assemblies. tool in rig selection.50 0 29.00 591.25 470.50 9.75 22.00 22. However.25 349.75 396.00 5. The real dai- each rig used in this study. TABLE 1-TIME DISTRIBUTION (hours) CONTINUED Nipple- Up and Casing Waiting Nipple.00 9.75 22..50 9.00 25.25 19.00 12.50 9.00 0 0 0 0 0 27. The efficien- fields.00 9. a relative measure of rig performance.00 14. This inefficient rig is costing the operator and Rig Efficiency.25 10. waiting on service companies. the effective daily rig cost can The "Other" column includes time spent on reveal substantial cost differences and can be a useful miscellaneous operations like working stuck pipe.50 6. The table ly rig cost" is simply the rig's actual daywork price includes contractor-controlled operations and additional divided by its efficiency for the particular drilling area.25 9.50 16. Table 1 also presents the OCCT divided by the TCCT for each rig.00 508.50 17.50 10.25 776.50 9. then rigs of equal effi.50 328.25 6.50 20.50 14.00 260.75 8.50 9.00 0 0 0 0 0 27.75 14.75 26.00 5. Table 1 presents the time distribution for contractor more to operate on a daily basis. several parent it was impossible to attain 100% efficiency in all were operating very close to the optimum. routine drilling operations experienced while drilling.50 13.75 26.75 MARCH 1984 491 .50 762. Table 2 shows that at least is being drilled.00 331.75 24. When rigs are compared.50 223. Total and on Down Testing Drillstem Squeeze Directional Operating Cementing Cement BOP BOP Test Plugback Cement Fish Work Connection Other TCCT Time ----.75 504.00 371.50 730. rigging up surface equipment.75 738.00 764.50 0 0 0 0 0 29.25 5.75 18. ly cost of a rig to the operator or contractor can be tained directly from the daily IntI.25 8.50 6.00 8.50 73.00 8.25 5.25 19. 832 12.500 23. optimal operating time for a particular field provide a daily measure of overall drilling cost.311 3. Rig 1 7. These other the minimum times shown in Table 1.24 12.400 97 5.600 89 6. and any other daily drilling expense.25 328. water.50 591.620 9.2 I Contractor G.75 508.8 3.578 3.400 65 8. Other daily costs besides can be calculated from Relationships 7 and 8 by using rig costs are associated with drilling wells.330 75 9. Rig 1 6. Rig 1 504. mud.527 East Texas-Field C Contractor A.700 83 8.25 230.75 567.800 70 8.8 3.072 3.752 12. Rig 1 5.771 10.25 70 I I I I Contractor H.915 3.400 77 8. Total operating days evaluating drilling performance is the overall cost to the can then be calculated for each rig by Relationship 6.500 31.500 17. Effective Daily Fixed Cost.500 37.500 94 6.2 Contractor D.500 48.25 65 7 $1800/DAY REDUCTION South Michigan Contractor H.1 North Michigan I I Contractor G.89 24. This cluding both contractor-controlled and operator- fixed cost is incurred every operating day and is influenced operations.25 96 Contractor C.500 28. Rig 1 6.3 4. Rig 1 6.254 Contractor H.00 260. Rig 4 5.25 68 Contractor H.500 36.187 492 JOURNAL OF PETROLEUM TECHNOLOGY . Rig 1 504.250 93 6.43 26.800 99 5.75 97 Fig.308 3.812 10.4 4. overall efficiency of the entire drilling operation.50 580.500 19.75 962. ship 5. Relationship 10 combines the ef- the concept previously used in calculating rig efficiency fective daily rig cost and the effective daily fixed cost to is applied.072 13. Rig 1 6.75 99 Contractor E.949 Contractor E. (Relationship 9) therefore represents the real fixed cost A rig's daily fixed cost can be calculated with Relation.8 4.90 13.8 6. labor.25 34. associated with the rig's overall drilling efficiency.720 3.941 3. in- mud logging.8 4. The "effective daily fixed cost" therefore a function of the operating time for each well.76 26. Rig 2 504.25 95 Contractor S. Rig 1 738.50 736.75 892. rental equipment.8 5.349 Contractor S.577 14.78 24.690 9. The total operating time for each rig studied is summarized in Table 1 and is the sum of the time spent Effective Daily Drilling Cost.67 12.3 4.50 75 Contractor F. Rig 2 259.25 99 650~ : WELL No.76 26.500 30.1 Contractor D. Rig 2 5.00 83 East Texas-Field S WELL No.50 74 t WEll No. Rig 1 6.00 13.00 55 I I Contractor H. 2-Field results-Contractor H.75 674.50 94 8307 Contractor E.513 North Michigan Contractor G. The bottom line in in every category listed in the table. If operator or contractor.869 13.500 20.500 47.8 3.8 4.696 10.59 13.773 Contractor H.062 15.00 470.873 11. Rig 4 223.608 14. Rig 1 548.380 South Michigan Contractor H.034 10. Rig 1 738".880 Contractor H.286 3. Rig 1 738.00 396.55 13.500 14.180 Contractor D.500 29.3 3.50 34.250 95 6.292 3. The ratio of total costs are called a rig's "daily fixed cost" and include operating days to optimal operating days indicates such items as fuel.500 34. Rig 1 5.968 13.330 74 9.400 68 7.41 34. This ef- TABLE 3-EFFECTIVE DRILLING COST Effective Effective Effective Daily Daily Daily Daily Daily Rig Rig Rig Fixed Total Optimal Fixed Drilling Cost Efficiency Cost Cost Operating Operating Cost Cost ($) (%) ($) ($) Days Days ($) ($) East Texas-Field A Contractor A.40 24.400 55 9. Rig 1 259.4 3.158 99 7. Rig 1 548.8 3.773 3. Rig 2 259.8 4.75 776.533 Contractor S.467 Contractor C.500 26. Rig 2 5. TABLE 2-RIG EFFICIENCY Rig OCCT CCT Efficiency (hours) (hours) (%) East Texas-Field A RIG EFFICIENCY (%) Contractor A.00 93 Contractor S.905 3. Rig 1 259.75 34. Rig 3 223.230 3. Rig 3 5.103 Contractor E.818 3.350 Contractor F.00 89 0 50 65 83 00 18% ICREASED EFflCIENCY East Texas-Field C EFFECTIVE DAILY RIG COST ($ 1000/DAY) Contractor A. Rig 1 548.549 Contractor G.00 371.567 3.500 96 6. Rig 1 5. Rig 2 7. Rig 1 7.4 4.75 77 WEll No.500 13. Rig 2.75 764.824 East Texas-Field S Contractor D. Rig 1 738. Rig 1 6.235 10.771 3.859 3. This a practical measure of drilling rig performance.2 10. Rig (hours)!24 hours No. Trip time is the total hours required for nor- This method of calculating rig performance requires a mal drilling operations associated with changing the drill data base for accurate calculations. Rig support of the drilling staff in helping compile some of lubrication is controlled and performed solely by con- the data needed for this paper. Table 3 shows the 4. achieved 65% efficiency and $8. OCCT (hours) = total of minimum times in: cluded in this study. This should result is not recommended for improving efficiency. which time is influenced by the operator's decisions. ly rig cost + effective daily fixed cost Conclusions APPENDIX B The effect of the contractor's personnel on the drilling Glossary of Contractor-Controlled Time operation should be included when rig efficiency is evaluated. APPENDIX A Rig Repair Time. we have be included unless it is a normal part of the drilling pro- used this method effectively in areas where limited data gram or the trip coincides with a scheduled bit change. excluding reaming time. Fig. Optimal operating time (hours) = total of minimum daily rig cost after drilling Well No. 8. thereby reducing overall is considered contractor-controlled because it is directly drilling cost throughout the industry. Effective daily rig cost ($/day) = daily rig rate/rig combined effect of rig efficiency and the efficiency to efficiency) = (daily rig rate/Relationship 3) perform all other drilling operations as the effective daily 5. Trip Time. Effective daily fixed cost ($/day) = (daily fixed cost well and that the effective daily rig cost decreased x total operating days/optimal operating days) $1. for Lube Rig Time. We also appreciate the grease the rig to maintain proper rig operation. Trip time associated with a drillstem test should not will improve accuracy of the results. Acknowledgments We thank the management of Amoco Production Co. A larger data base bit. Thereafter the improved efficiency of Rig No. A computer program would greatly aid in Trip time resulting from washouts in the drillstring are to evaluating rigs. it should be excluded from the total rotating The concepts discussed are currently applicable in hours.2. with limited use in wildcat item in a drilling area where the drilling program is drilling areas. Therefore. 1. Drilling time is considered a contractor-controlled development drilling areas.307 effective 7. Lubrication time is the time required to permission to publish this paper. Total operating days = total operating time method of evaluating rig efficiency. Drilling time is the total rotating hours cludes both rig and rig crew performance. especially in areas of high activity. This method of calculating rig efficiency in.800.fective daily drilling cost can be used by the operator or BOP's) + (cut drilling line) + (rig up) + (tear contractor to evaluate rigs on a complete cost basis. 2 shows an example of results obtained with this 6. Rig repair time is (drill) + (trip) + (lubricate rig) + (repair rig) + contractor-controlled because it reflects the condition (connection) + (nipple-up BOP's) + (nipple-down and operating practices of the rig and rig crew. MARCH 1984 493 . (mud logger) + (rental) + (miscellaneous) Fig. be included because they reflect the condition of the rig equipment and the contractor's operating practices. We also have 3. which is a practical measure of the overall labor) + (contract labor) + (fuel) + (water) + drilling performance. tractor's personnel. After the meeting. CCT (hours) = total of rig time in: proper continuous operation of the rig. Contractor H was con.2 in each contractor-controlled included in OCCT) category. 2 shows (hours)/24 hours that Rig No. Optimal operating days = optimal operating time vinced that improvements could be made. Note The concepts discussed in this paper are intended to that increasing trip speed may lead to unsafe drilling provide the groundwork for developing a more uniform practices such as excessive swab or surge pressures. However. Drilling Time. Rig efficiency = OCCT/contractor-controlled time seen that a rig's efficiency remains relatively constant = (Relationship 2/Relationship 1) when it is operated in different fields. A meeting was time in: held with the contractor to discuss the concept and the Relationship 2 + (summation of minimum time not performance of Rig No. This provides required to drill a well.2 efficiency improved 18% in a subsequent 9. associated with drilling time and is a function of the rig and crew. (drill) + (trip) + (lubricate rig) + (repair rig) + (connection) + (nipple-up BOP's) + (nipple-down Investigation of Results BOP's) + (cut drilling line) + (rig up) + (tear From the data contained in Table 2 we have been able to down) determine that rig efficiency varies greatly. are available. 2. down) These costs are summarized in Table 3 for the rigs in. mathematical model of this type of rig evaluation for use in rank wildcat drilling areas. Work is under way to develop a relatively uniform. Trip time in more efficient rig operations. can aid in rig contract negotiation and rig selection. Daily fixed cost ($/day) = (mud) + (supervisory drilling cost. Rig repair includes the time to repair Relationships Used in Analysis any component of the drilling rig that directly effects 1. and method of evaluating rig performance. Effective daily drilling cost ($/day) = effective dai- has been maintained. Contractor H. This category includes time to time it takes to slip and to cut the drill line. Rig-up time begins when the derrick and ly is picked up for making a connection and ends when rotation begins for drilling new hole. a contractor-controlled item. 14. ready to begin drilling operations. Paper accepted for publication June 8. 494 JOURNAL OF PETROLEUM TECHNOLOGY . Excessive testing time down. this delay should be omitted. Connection time starts when the kel- Rig-Up Time.Cutting Drill Line Time. Connection time is contractor-controlled performed by contractor's personnel. Connection Time. 1983. However. held in New Orleans Feb. Nippling down the BOP's normal practice on each well studied. Reaming and substructure are on location and ends when the rig is washing to bottom should not be considered as connec. excessive time because of failure of the JPT BOP test equipment should be excluded because this Original manuscript received in Society of Petroleum Engineers office Jan. contractor's personnel. Tear-down time starts when the rig is takes to assemble and to conn~ct the BOP system for released by operator and ends when the derrick is laid operationally safe drilling. delay is caused by outside service personnel. if a because it is a function of the rig crew and equipment. therefore. 20-23. Rigging down is also usually performed by the because of leaks or faulty connections should be includ. This operation is defined as the time it Tear-Down Time. This practice disassemble and disconnect the BOP's to change is contractor-controlled and should be included if it is a preventer size or rig-down. However. This category includes the Nipple-Down Time. Revised manuscript received Nov. function usually is performed by someone other than the 1983. Nipple-Up Time. Rigging up is usually tion time. 25. usually is performed by the rig crew and is. 1983. ed. Paper (SPE 11364) first presented at the 1983 IADCISPE Drilling Conference drilling contractor.
Report "A Practical Method for Evaluating Rig Performance"