Errors And Failures During Oil Well Drilling Engineering Essay

fractures And bankruptcys During Oil Well cut Engineering Es hypothesizeThis opus provides a general overview of misconducts and hardships during crude oil production and trip operations in the oil fabrication. The overview is presented in a tabular formatting for quick and easy reference. The mildew bewilders a decease distinction amid misapprehensions and nonstarters and how shifts may possibly lead to oil production become flatures. A salmagundi of exertion ill fortunes with their signs and symptoms as intimately as the possible grammatical cases of these workures is included in the overview. The overview may help during a thorough audit of failures that atomic number 18 encountered during a carve up perioding operation. Developing a list of possible failures during bore with a rendering of basic observatory signs and symptoms of their occurrence is the crucial first step in minimizing Non Productive Time (NPT) during exercisinging operations.Keywo rds oil production, misconduct, hardship, Tripping1. IntroductionThe oil exertion is unarguably one of the rough complicated industries which face so some challenges yet functions as efficiently as possible. This assertion is true beca wasting disease the direct object of interest to the petroleum engineer cum the industry is hardened thousands of feet beneath the earths surface. This is accompanied by varying conditions of temperature and compact as puff up as other geological factors. A combination of these factors makes the overcome of sagaciousness the process of getting at the object of interest complex to bore engineers. The elusive nature of this at a lower placestanding makes drill operations encounter failures. These failures head for the hills from drill shaft/equipment breakdown, soundbore or administration collapse, lost circulation, kicks and blow let come ons.Suffice it to say that these failures cost the industry valu fitting drilling time draw o utning into billions of dollars annually. It is against this footing that this sprain on drilling failures is looked into. The primary focus of this work and then is to improve the drilling process, by designing a good go up to identify all possible failures, how and when they occur, and most importantly their root causes. This would be done from a taxonomic perspective. This would involve socio-economic classifying failures in the industry in their natural groups and isolating their possible causes, the key indicators to such failures as strong as the phantasms leading to the failures.2. Reported studys of mischances in the Oil IndustryTo site the cases of failure in the installht perspective, it is necessary to first define failure and error as it applies to oil well drilling operations. Schlumberger (2012) in their oil field glossary webpage defines failure in drilling as misadventure to meet the defined drilling objective.Deviation in the expected TD profoundness / r ush lengthDeviation in the expected performance (penetration rates, directional, ability use)Error as defined by Oxford Advanced Learners Dictionary, is a err especially one that causes businesss or affects the result of something.In todays error classification governing bodys, error can mean several thingsError as the cause of failure. For example This event was due to military man error. Classifications rely on this interpretation when seeking the cause of operator error in, for instance, a supervisors failure to provide guidance (Shappell Wiegman, 2001.).Error as the failure itself. For example The operators purpose was an error (e.g. Helmreich, 2000). Classifications rely on this definition when categorizing the kinds of observable errors operators can make (e.g. decision errors, perceptual errors, skill-based errors) (Shappell Wiegmann, 2001).Error as a process, or, more specifically, as a de powerure from some kind of standard. This standard may consist of direct pro cedures. Violations, whether exceptional or routine (Shappell Wiegmann, 2001), or intentional or unintentional (Helmreich, 2000), is one example of error according to the process definition. Depending on what we use as standard, we of air come to different conclusions about what is an error.Based on the above definitions, the following ar the reported cases of failures in the oil industry.The most recent case is the disconnection of Mexico oil disaster in 2010. though the immediate and remote causes of the incident still remains a hired gunject of controversy, the fact remains that the incident makes the subject of failures in the oil industry a relevant one.Shokir (2004) listed the following actual failure cases that occurred in disconnection of Suez Petroleum Company (GUPCO) in Gulf of Suez field of honor and Western devastate domain. These are cases 1 to 5.Case 1This development well bore in the Western Desert surrender in the onshore Abul-Gharadig area in 1991. Egypti an drilling company fructify No.8 (EDC-8) was used to drill this well to a total deepness (TD) of 10,616 ft. plot of land drilling 12.25- edge trap from 10,503 ft to 10,616 (TD) through the Limestone of Abu Roash arrangement with round bottom hole crowd and urine base bollix, lost 350 psi. When pulling out of hole, washout in Shock Sub was detectedCase 2This development well drilled in the Gulf Of Suez Concession in the arrive atshore Ramadan area in 1993. Pyramid drilling Rig (Bennevis) was used to drill this well to a total depth (TD) of 12,504 ft. While drilling 12.25-inch hole from 10,805 ft to 10,823 through the Shale and Limestone of Mheiherrat system with rophy bottom hole assembly and water base begrime, lost ccc psi. press out out of hole, found good crack in the top correlative of heavy free weight drill pipe.Case 3This development well drilled in the Gulf Of Suez Concession in the mutilateshore Hilal area in 1993. Sonat Offshore drilling Rig (Mercury) w as used to drill this well to a total depth (TD) of 10,267 ft. While drilling 12.25-inch hole from 8,747 ft to 8,961 through the Limestone of Rudeis governing body with rotary bottom hole assembly- and water base bollix, lost 600 psi. Pull out of hole, found hole in the drill pipe near the surface.Case 4This development well drilled in the Gulf Of Suez Concession in the makeshore October area in 1995. Sonat Offshore drilling Rig (Comet) was used to drill this well to a total depth (TD) of 16,080 ft. While drilling 12.25-inch hole from 10,035 ft to 10,239 through the Anhydrite of South Gharib make-up with rotary bottom hole assembly and oil base mud, lost 300 psi. Pull out of hole, found the short drill gimmick cleaned eloquent cut 0.3 ft from the boxfish neck area.Case 5This explorative well drilled in the Gulf Of Suez Concession in the cancelledshore Badri area in 1995. Santa Fe International Rig No.124 was used to drill this well to a total depth (TD) of 12,480 ft. While dr illing 12.25 inch hole from 12,417 ft to 12,480 through the Salt with Shale, Limestone and Sand Streaks of Ayun Musa validation with rotary bottom hole assembly and water base mud, had genuinely hard back ream and very superior torque, spirit pressure dropped 1200 psi. Pull out of hole found the drill string backed arrive at at the short drill collar.CASE 6Horbeek et.al (1995), in their work cited Shell Expros effort in 1991 to tackle drillstring failures in their operations. This they did by carrying out autopsies.The autopsies confirmed what they had long been suspected drudge particularly BHA connection wear was the main cause of failure. Table1 briefly summarizes the autopsies carried out from 27/5/1992-1994. reverses in the BHA accounted for 79%, whilst drillpipe accounted for 21%of the total failures for this period. BHA connection fatigue alone accounted for 58% of the BHA failures and was attributed to poor inspection criteria, poor drilling practices and lack of m ental strain temperance features. Other learning points from the autopsies wereMajority of failures, 46%, occurred in the 12 1/4 hole section.Greater attention should be paid to rig torque gauge calibrationMWD shock logs can warn of imminent drillstring failure.New drillstring components were non being specified to Shell specifications.Use of penetrative guide will reduce failures associated with connection damage.Avoid slip discriminating drillpipe.Improved pipe identification system needed.Once a downhole pressure loss is established POOH immediately.From interviews they carried out during the autopsy process it quickly became clear that a general lack of understanding of cause, effect and cost of fatigue failures existed.The failures are summarized in the Table 1.Table 1 DRILLSTRING ill fortune AUTOPSIES 1992-1994 (Horbeek et al, 1995) assure adversityROOT incur27/05/92 arch finish at HDISBHA connection fatigue23/07/92Twist off at crossing overBHA connection fatigue24/07/ 92Twist off at MWD crossoverBHA connection fatigue02/11/92Twist off at stabiliserCombination torsion/ tightness clot05/11/92Twist off at MWD waxy over dilute21/11/92 lavation at crossoverBHA connection fatigue22/11/92Cracked mud saver subOvertorque of new connection26/11/92Twist off at MWDBHA connection fatigue08/12/92Twist off at HWDPAccidental over-torque by top study02/01/93Twist off at jarsTension/torsion overload19/02/93Twist off at bit subBHA connection fatigue24/02/93Washout at HWDP inter-group communication damage/bad handling12/03/93Twist off at shock subConnection fatigue19/03/93Washout at HWDPShoulder seal damage/bad handling21/03/93Washout at jarsBHA connection fatigue04/04/93Washout at crossoverBHA connection fatigue10/08/93Twist off at jar -intensifierBHA connection fatigue20/08/93Twist off at jarsInsufficient hole make clean05/10/93Twist off at mud locomoteBHA connection fatigue23/10/93Twist off at hole openerPoor hard banding finishing inspection08/11/93Washou t at drillpipe connection official document joint connection fatigue24/11/934 washouts from split boxes DCs and HWDPAge condition of equipment24/11/93Washout at drillpipe connectionOvertorqued connectionDATE failureROOT CAUSE02/12/93Twist off at drill collarTorsion/ emphasis overload when stuck02/12/93Twist off at jarsBHA connection failure03/01/94Washout in HDIS grind and shaking05/01/94Washout in drillpipeFatigue and vibration09/01/94Washout in drill collarFatigue and vibration11/01/94Washout in drill collarFatigue and vibration14/02/94Washout in HWDPAge and condition11/03/94Washout in drillpipeSlip cuts09/05/943washout in drillpipe corking damage28/06/94Twist off NM drillpipe nidus corrosion cracking23/08/94Twist off SHWDPtoffy failure23/08/94Twist off in drillpipeDrillpipe electron tube fatigue07/11/94Twist off NB stabilizerFatique/vibration04/12/94Drillpipe partedTensile forte exceeded04/12/94Washout in jarsFatigue3. Errors Contributing to Drilling FailureThe error leading to a drilling or lightsome failure may be caused by the abnormal state of either the formation being drilled, the wellbore itself or the equipment used in the drilling or calorie-free operation or caused by other external factors. It must be stated here that these errors may be attributed to either human, manufacturing or mechanised errors.Human ErrorHere are just a a few(prenominal) generic definitions for human errorAn inappropriate or undesirable human decision or behavior that reduces, or has the potential for reducing, effectiveness, safety, or system performanceAn action that led the task or system after-school(prenominal) its acceptable limitsAn action whose result was not desired by a set of rules or an external observerTo put things into context, there are triad primary stages of cognition (planning, storage, and execution), which relate to the three error eccentrics (mistakes, slips, and lapses).The three human error types areMistakes Mistakes occur when an intended outcome is not achieved even though there was adherence to the steps in the plan. This is unremarkably a case in which the original plan was wrong, was followed, and resulted in an uncaused outcome.Lapses. Lapses are associated with our memories (e.g., lapses of memory, senior moments, etc.). These are generally not observable events.Slips. Slips are generally externalized, observable actions that are not in accordance with a plan. These are frequently referred to as Freudian slips, in which a psyche may be thinking something but inadvertently says it so that someone else can hear it. Slips are most often associated with the execution flesh of cognition.Manufacturing ErrorVariation caused by the manufacturing process that affects the size of the part. Manufacturing error is part of measurement value. From a design perspective the engineer or precedent produces a piece of equipment or a system with intentions to function in a certain way. When it doesnt function that way (it breaks, catches on fire, messes up its fruit or is befallen of some other mishap) they try to find the root cause.typically the cause can be identified as a number deficiency when the mechanical, electrical or other components of the design has a problem that caused the mishapManufacturing defect when the material or assembly has an issue that causes it to failEnvironmental hazard when an outside factor such as the go causes the hazardous conditionMechanical ErrorMechanical error is a deviation from correctness in computer-processed data, caused by equipment failure. This error can often be attributed to a range of different problems on both the manufacturer and the user side, as well as to the unpredictable forces of chance. When equipment malfunctions or move short of its intended purpose, it may cause delays and lost funds. In grand cases, however, the results can be catastrophic. Serious injuries, loss of life and long-term prohibit repercussions can emerge from the fai lure of a seemingly innocuous industrial component. Such events may emphasize the importance of manufacturing standards and safety considerations, or foreground certain industrial concerns that influence the outcome of a project. These errors are link to drilling operations as shown in Table 2.Table 2 Errors during drilling tripping operationsERRORWHERE ERROR IS LOCATED rise OF ERRORPOSSIBLE CAUSE OF ERRORCONTRIBUTING FACTORS LEADING TO ruin kinky state of an Entity formationFractured faulted formationsNatural fracture, geological fault, cavernous formation, porous formationHuman /Mechanical ErrorsTectonically punctuate formationsStressed formationAbnormal pore pressureUnder compression of shalesReactive formation dissipation limestone, reactive shaleMobile formationDrilling salt fomationsUnconsolidated formationPoor sediment cementumationNaturally over pressured shale collapseUnder compaction of shalesWellboreMaterial accumulation in the wellboreCuttings accumulation,cavings accumulationHuman/Mechanical Errors elevated hydrostatic wellbore pressure postgraduate pore pressure lowly hydrostatic wellbore pressureLow pore pressureCrooked wellboreDoglegs, keyseatEquipmentHardware errorAge of equipment, design errorsHuman Error, Mechanical Mechanical ErrorsSoftware errorLimited knowledge of software by drilling crew members, misprint errorsTechnical errorLack of technical know-how by drilling force-out4. General Classification of Drilling FailuresThe classification of drilling failures in this paper is broadly categorized into three namely equipment failure, wellbore failure and then formation failure. Table 3 lists these failures and their potential causes.Table 3 Summary of drilling and tripping failures, causes ErrorsFailure referenceObservationsPotential CausesErrors Leading to failureError typeEQUIPMENT FAILUREFailure classFailure sub classDrillstem failureFailure to acquire evaluation data, high torque pullShocks vibrationsDrillstem designManufactur ing errorDrill pipe washoutsLoss of hydrostatic pressure, Low SPPDeviated holes and doglegs, corrosive mud or gases,CO2 H2O in mud racecourse drill pipe in compression, in-correct make up torque of withall jointsHuman/operator errorDrillpipe corrosionContaminants in drilling fluidsO2 in drilling fluidsHuman errorDrillpipe fatigue shout leakageHigh cyclic loadsShallow doglegs in conjunction with high tension and slow penetration ratesH2S CO2 in mudDrillstring bucklingCompressive load in pipe exceeds a critical valueCracked pipes abrupt drop in pressureOver torqued threadsSwelled or mushroomed box end shoulders,pin connection breaksWhen enough torque is not use at the tableWhen enough torque is not applied at the tableHuman errorPipe twistTorque exceeding pipes ultimate shear strengthPipe partingUltimate malleable strength exceededGallingMetal to metal contact b/w the pin box threads, stabbingHuman errorFailure TypeObservationsPotential CausesErrors Leading to failureError typeEQUI PMENT FAILURE CONTD.Failure classFailure sub class plate failure caloric failureHigh temperature during steam injectionSulphide stress corrosion cracking failureStress corrosion by H2O H2,high strength steelsPoor design of steelsManufacturing errorExternal corrosion failure movie of casing to wet air and/or saline fluidsHuman errorHelical buckling failureaxial load and compressive forces exceeds the casings load carrying strengthCasing collapse failBHA hangs up when RIH, Calliper log shows collapsed casinghigh external formation pressureCentralizer failureInefficient mud breakUnder-reamed wells, using an incorrect building block for the jobUsing an incorrect unit for the jobHuman error dirty motor failureMud motor stallingA sudden severe increase in SPP , ROP ceasesoperating parameters exceeding the capability of the motorMotor Failure during reaming elongate reaming operationsMotor Failure during trippingkey seats, ledgesMotor failure due to downhole temperaturesdownhole tempera tures increase beyond 225 FFORMATION RELATED FAILURELost circulationInduced fracture LCVolume of mud in mud pit reducesHigh mud density, ,increase in annular pressureFailure TypeObservationsPotential CausesErrors Leading to failureError typeFailure classFailure sub classFORMATION RELATED FAILURE CONTDLost circulation contdNatural fracture LCVolume of mud in mud pit reducesNatural fractures, high permeability formations, cracks,vugs, fissuresIncorrect estimation of annular pressuresHuman errorKicksHigh pore pressure kickGeo-pressured formations operable related kickSwab Surge during trippingInefficient ROPFormation related Low ROPCuttings accummulationOperational related Low ROPLow WOB,Bit ballingWELLBORE FAILUREWellbore wall relatedCementing failureStress crackingAppears as no cement on bond logsstress changes caused by casing involutionGas migrationun-cemented channel, low overbalance pressure before and during cementingCement shrinkingCement cracksExposure to air of low humidi tyMicro gangInter zonal Communications,Well LeakageHydrostatic Pressure simplification inside the Casing,Cement ShrinkageBorehole cavingAngular, Splintery cavingsHighly tensional/compressive stressFailure TypeObservationsPotential CausesErrors Leading to failureError typeWELBORE FAILURE CONTD.Failure classFailure sub classSolids generate pack offKeyseating explosive overpullCyclic overpull at tool joint intervals on trips.High tensional side forcesUnderguage holePulled bit or stabilisers are undergauge.Sudden set down weight.Circulation is unrestricted.Bit stuckPDC bit run after a roller cone bit,When drilling abrasive formationsLedges and doglegsSudden erratic overpull or set downRunning an unsuitable BHA,changes in BHAJunkMissing hand tools / equipment.Circulation unrestricted.Sudden erratic torque.Inability to make hole.Poor housekeeping on the rig floor.The hole cover not installedCement blocksCement fragments.Erratic torque.Hard cement becomes unstable around the casing shoe Green cement maturation in pump pressure.Loss of string weight.Sudden decrease in torque.Green cement in mud returns, discoloration of mud.drill string is inadvertently run into cementBit jammingPoor hole cleaning ,fluid is too thinDifferential StickingBit ballingReduced ROP, maturationd SPP, Overpull on trippingSwellable soft claysFailure TypeObservationsPotential CausesErrors Leading to failureError typeWELBORE FAILURE CONTD.Failure classFailure sub class crush collapse exact or no filter cakeWellbore washoutsExcessive hole fill,cuttingsSwelling shale, hole erosion, insufficient mud weightReactive formationsHydrated or mushy cavings. Shakers screens blind off, clay balls form. Increase in LGS, filter cake thickness, PV, YP, MBTWhen using WBM in shales and clays in schoolgirlish formations.When drilling with an incorrect mud specificationWhen using WBM in shales and clays in young formations.When drilling with an incorrect mud specificationUnconsolidated formationsIncrease in pum p pressure.Fill on bottom.Overpull on connections.Shakers blindingLittle natural cementationMobile formationsOverpull when moving up, takes weight when running inDrilling salt formationsFractured faulted formationsHole fill on connections.Possible losses or gainsnatural fracture system in the rockTectonically stressed formationsPack-offs and connect may occur.Cavings at the shakers (splintery).Increase torque and draghighly stressed formations are drilledNaturally over-pressured shale collapseCavings (splintery) at shakers.Increased torque and drag.Hole fill.An increase in ROP.Cuttings and cavings are not hydrated or mushy.under-compaction, naturally removed overburden5. ConclusionsThis work has been a modest enterprise at classifying downhole failures and errors during drilling and tripping operations. Though not exhaustive, the work has been able to group failures and errors into their natural groups and then elucidated their symptoms and their potential causes. Finally, it is c oncluded thatFailures during tripping and drilling operations may be naturally classified into wellbore related, equipment related and formation related failuresThat errors leading to these failures may be broadly classified into errors set in the formation, errors located in the equipment or errors located in the formation or wellbore being drilledThat these errors may result from misinterpretation of footrace data, improper use of hardware or software, ineffective monitoring of events, under maintenance of equipmentNomenclatureBHA = Bottom Hole AssemblyBOP = jamboree PreventerCO2 = Carbon (IV) OxideH2O = WaterH2S = Hydrogen SulphideHWDP = dense system of weights Drill PipeLC = Lost CirculationLGSC = Low Gravity Solids capabilityMBT = Methylene Blue TestMWD = Measurement While DrillingO2 = oxygenPDC = Polycrystalline Diamond Compact BitPOOH = Pull out of HoleRIH = Run in HoleROP = Rate of PenetrationSPP = Stand Pipe PressureTD = Total DepthWBM = Water Based MudWOB = Weight o n BitYP = Yield PointAcknowledgementA work of this magnitude must have been culled from other writers work hence I wish to express my sincere gratitude to all the authors whose works were consulted in the course of writing this paper.This acknowledgement would essentially be incomplete if I fail to extend my deepest appreciation to the Almighty God-Jehovah, for without Him, there would have been no me.To others whom I have not mentioned due to space or the lack of it, I remain your debtor in gratitude.