Drilling钻井实例

Use of a Life Cycle Drilling Simulation System on a Challenging HPHT Drilling Operation in the Norwegian SeaLaurie Scott,Wintershall;Just Sverre Wessel,Maersk Training;Josef Nabavi,and Rolv Rommetveit,eDrilling SolutionsAbstractA Life Cycle Drilling Simulation System(LCDSS)was utilized during planning,training,and operation in support of a very challenging drilling operation in the Norwegian Sea.The LCDSS constitute a total modeling system tailor-made for planning,advanced training real-time simulation and decision support.In order to utilize the LCDSS,the work processes were modified and fit-for-purpose communication lines were established.In preparation,an advanced training session was performed using a dynamic downhole training simulator linked to a topside rig simulator,for training of the drilling teams.Prior to operation data transfer was established so that during the operation simulations was performed in real time using the ongoing operational parameters as input.Automatic look-ahead simulations of ECD and temperatures were performed with the calibrated models on the fly as support for decisions.Every day drilling forecasts were made12to24hours ahead.This was done by means of a transient planning model populated with all relevant data from the operation.These forecasts were communicated to the drilling team as a basis for the upcoming operation.This paper will first present the Life Cycle Drilling Simulation System,then elaborate on the use of this in the preparation/training phase and operational phase including forecasting.Special focus will be given to how the work process and communications were modified and the results thereof.The operation was successful,and the LCDSS was a contributor to this.IntroductionHistorically a significant proportion of the industrys lost time has come from poor understanding of the risks associated with incorrect ECD,pore pressure and fracture gradient estimations and interpretations. The scope of work was to establish a common platform where cross discipline collaboration could assess and manage the risks associated with PPFG considerations throughout the well construction process specifically to safely and effectively construct the well within the actual operating envelope.Copyright2016,IADCMiddleEastDrillingTechnologyConferenceandExhibitionAs a strategic concept this platform was constructed from a bottom up perspective,where the team was focusing on finishing a section without exceeding limitations.The real time simulations team was focused on limiting the extra workload on the Wintershall operations team,and act as an Љinvisible add-on Љ,and simulatanously allowing the Wintershall team constant access and information.The first step stone was to develop a risk register updated with Wintershalls identified risks and shared between the Wintershall team and the remote center operators.This 3D risk register was from then on continuously updated with relevant findings during the well construction.The presentations of these risks and the updates were displayed by means of a 3D plot illustrating the measured and anticipated downhole limitations.The information displayed,along with the operational considerations and recommendations were actively used by the Wintershall team in order to make proactive decisions during the well construction.The remote center was teamed up with model operator along with operational experienced resources in order to deliver the best possible product to the Wintershall team.The well was drilled within time and budget despite numerous WOW and hang-off’s,and one disconnect.The Live Well Support service on 6406_2-8Imsa was started on 4th February 2015.The well was drilled as a vertical exploration well in Haltenbanken,Norwegian Sea,with the semi-submersible rig Transocean Arctic.Life Cycle Drilling Simulation SystemThe Lifecycle Drilling Simulation System (LCDSS)utilized in this work consist of advanced dynamic drilling models and diagnosis technology merged with 3D visualization into a Љvirtual wellbore Љ.The interaction between the various drilling models are seamless,and used in the whole drilling value chain from planning though training and subsequently RT operations with forecasting.5–9The core technology consists of advanced mathematical models developed,tested and verified over 20-years in operation 1–4combined with a highly advanced modular engine &downhole 3D Virtual Well.Work Process ModificationsIn order to set up the LCDSS delivery,it became apparent that the existing structure of communication and work process had to adopt the delivery of this service.Therefore a thorough evaluation had to be done in order to properly include the service into theoperation.Figure 1—2Since the LCDSS service was based on the previous given training to the core crew,the well and well data was already integrated in the system.Hence a holistic approach to the work process task was agreed,using previous experiences and learning points.However the main challenge was to ensure that the operator was allowed access to relevant data when needed without interfering with their everyday tasks.To achieve this,a strong communication line had to be established,to ensure the communication worked optimally between rig,operator and remote center.The remote center were allowed access to the main document center,and included on the relevant mailing list to get access to all necessary data.This allowed the majority of the information flow needed,to be covered without interrupting the operation,or adding major additional tasks to personnel.To be able to deliver a meaningful service,the remote simulation center had to ensure a full understanding of the risk picture for the drilling campaign,and full involvement in the well delivery process.As a part of the work process modification,the training session was used to evaluate the modifications and the implementation towards the rig and onshore operation.The teams concluded rapidly that the rig should not be included as a part of the communication line,to ensure that the rig had full focus on interpreting the well and the signals the well portrayed.If necessary the communication line could be opened to the rig.The aim was that the daily communication should be between Remote Center and the Drilling Superintendent,illustrated in Figure 2.It was then the drilling superintendent’s responsibility to inform and utilize our service towards the rig as he saw fit.When the work process was established and agreed upon,a link was set up to WITSML data,where the functionality was tested towards the software.The main challenge was to ensure that the correct data from the WITSML source was connected to the right channel in order to provide meaningful data and trends.This was resolved during the implementation phase and tested in the 17½Љsection.During the 17½Љsection a series of testing and simulations were performed in order to tune the system correctly.The baseline defined was the PWD readings provided from therig.Figure 2—Illustration of the agreed communication lines 34The base delivery agreed was to use the3D visualization tool as an online risk register.This tool was accessible for the engineering team,and updated with the latest experiences and information gathered.This was judged to give the most value at the given time.The proactive simulations should be conducted and evaluated throughout the drilling campaign,but as a second priority.As a part of the information flow,agreement was made to meet on a daily basis to discuss the findings prior to the afternoon meeting with the rig.The aim with this meeting was to ensure that the risk picture was understood and agreed for the next24hours.During well construction of Imsa,automatic Look Ahead simulations of ECD and temperature gave the operations team valuable information prior to making decisions.The simulations provided a numerical approach to the limitations and downhole combined effects that had to be interpreted prior to establish-ment of operational recommendations.The numerical results along with the recommendations were issued to the operator on a daily basis prior to client meeting.During the operation,the operator was given a12to24hour forecast based on a transient planning model populated with relevant data from the operation using WITSML data combined with the non-automatic data needed like Mud Rheology,pipe tallys and updated PPFG reports.The forecast was communicated to Wintershall on a daily basis in form of a report issued prior to subsequently meeting. During the meeting the findings were discussed along with the recommendations.The remote centers task was initially to collect and update the risk register for an online display.This meant that all involved parties had a fully updated risk picture when needed in order to assist them in making the right decisions.However as the work commenced,it became apparent that the system available could assist the operation further by the use of transient models and the look ahead capabilities.Thereby the role for the remote center also gradually turned into a2nd driller on tour function,monitoring and assessing the downhole conditions with operational expertise and experience.This materialized into a cooperation between all parties with an overall common goal to deliver a well on time with no major incidents recorded.Furthermore this allowed Wintershall to use the resources available proactively in the operation.The forecast provided along with the operational advices,enabled the Wintershall team to base their decisions on a sound dataset and recommendations in order to make the best operational decisions moving forward.Advanced HPHT TrainingImsa well is located in an area where the geological structure is complex,leading to large uncertainties, where the pore and fracture pressure estimates from Hi to Lo case were close to400bar/5800psi.This implied that the Scope of work regarding training was to highlight these conditions to enable the rig to drill the well safely and to take these considerations into the planning and operation process.Before this training took place,the rig and the crews had undergone two earlier HPHT training sessions for two different wells,over a rather short time span.This ensured that the crew had the necessary competence for drilling in such a complicated geological well structure.Prior to the operation,an advanced HPHT training took place,focusing on the challenges and risks identified during the planning of the well.The main focus for this training was to agree and embed the operational procedures with the drilling team,allowing them to make the right critical decisions and deduction of the correct downhole status based on interpretation of the wellbore signals.The training was structured as a seminar covering the procedures and general overview of the Imsa well.Thereafter the procedures and interpretations skills were honed using a Dynamic Drilling Simulator where the team was able to practice and train as a team.The simulator was set up to replicate the anticipated well conditions for the Imsa well,with respect to trajectory,PPFG,BHA,Drill string,downhole temperature profile and the PVT properties for the base oil in order to give a realistic feedback to the students.During the drilling of the Imsa well,the operations experienced an influx.This scenario had been trained on using the full scale drilling simulator.It is the impression that the training given enabled the crew to identify the influx immediately and carry out the correct actions.Real Time Simulations during OperationsEarly well control simulation tools did not consider dynamic temperature,but only provided computations using the assumed Љbackground Љtemperature profile.It became clear that very important events could only be simulated using a dynamic temperature model.Therefore,the hydraulic modelling with integrated dynamic temperature computations was of high importance during the operation due to uncertain pressure profile as well as the high pressures and high temperatures experienced.The key elements provided in support of operations were real time simulations,forecast simulations prior to specific situations,visualization in a virtual wellbore and decision support.More details is presented in a later paper 10.The system set-up and simulations performed,did not allow us to predict the actual PP in the top of the reservoir section and the subsequent 450l influx.Real Time monitoringThe Imsa pressure window was very small in certain parts of the wellbore,and therefore it was important to calculate the ECD/ESD as accurate as possible in order to safely navigate through the narrow window.The models handle calculation of dynamic temperature,dynamic flow,cuttings distribution including cuttings slip velocity and the combined effect of these parameters on ECD.Based on realtime simulations and active monitoring of the combined effects,the ECD value was used proactively in order to optimize the drilling parameters.The figures 3,4,5,6shows some of the important effects real time,modelled during the operation.The plots are taken during drilling 12¼Љsection of thewell.Figure 3—Cuttings as well as RPM effects on ECD 5Figure 4—Cuttings and RPM effect on ECD,unstable measured ECD@PWD duringcirculationFigure 5—Temperature &SPP behavior during connection 6Figure 3and 4demonstrate modelled cuttings effect on ECD.There are no initial cuttings present in the wellbore prior to drilling.The ECD effect is relatively constant during circulation.As soon as drilling commences the combined ECD effect increases due to RPM increase and cuttings loading throughout the wellbore.Figure 3illustrates modelled ECD,Block position,Bit and Well depth.Figure 4contain more parameters like Flow in and calculated Flow out.It shows that the flow rate is constant during circulation and drilling.Variable parameters are RPM which change when drilling commence,and the cuttings concentration due to drilling,leading to higher ECD effect due to transpor-tation and distribution of cuttings upwards in the wellbore.The ECD continue to increase until cuttings reach the surface and the cuttings load in the wellbore is constant.One important factor is that the modelled ECD is stable during the whole operation;even though the measured PWD is erratic and unstable;see Figure 4.This illustrate that the advanced ECD model can function as a ЉVirtual PWD Љwhen the PWD does not work correctly.In Figure 5the modelled dynamic temperature effect and Stand Pipe Pressure SPP during connection are demonstrated.During drilling the temperature effect has reached the state of equilibrium leading to minimal changes in ECD,since the cuttings loading is relatively constant.The downhole temperature increases during pump off.When circulation starts the temperature decreases to near previous state.The process is affected by the pump off time,circulation rate,rotation rate,drilling rate and the difference between T Dynamic and T formation .Measured and modelled SPP are showing a very similar value and trend during drilling and connection.They are plotted together and trends are compared to see if deviations can be a sign of something unusualhappen.Figure 6—ECD &SPP behavior during connection 7In the plot below,modelled ECD effect and SPP are shown during connection.The ECD is constant during drilling and start to decrease when mud pumps are down and flow rate is zero.The ESD then stabilize close to EMW BHP (mud weight taken into account effects of temperature and pressure).The ECD increase when pumps are started after connection and stabilize afterwards.The straight line shows measured ECD which has no data during connection,while the modelled ECD at bottom hole and casing shoe reflects reality.Measured and modelled SPP show the similar value and trend during drilling and connection;such as the previous example.Real Time 3D VisualizationThe Real Time 3D Visualization can be used throughout the well operations.During the Imsa Well it was used to register the risk areas during the operation.The virtual 3D gauges were applied to visualize calculated ECD/ESD at potential risk zones such as casing shoe,bottom-hole and specific depths like Nise/Kvitnos formations and top of reservoir.All risks,such as loss and gain were updated according to signals from the wellbore,either experienced or simulated.Figure 7illustrates the use of 3D tool during running 97/8Љcasing.The picture shows 3D-view divided in three main parts;main window,gauges and 2D-tunnel.The main window is again divided into two parts.The upper part shows a typical rig and the lower part follow the drill bit.Bit Depth and ECD at bottom-hole sensors also follow the bit.The gauges are showing calculated ECD at bottom hole,casing shoe and Nise/Kvitnos formations.The bottom-hole and casing ECD gauges show normal values,while Kvitnos &Nise formation ECD gauge cross the red colour as the casing depth get closer to these formations.The last gauge shows Standpipe Pressure.The 2D-tunnel contain wellbore geometry,drill string,pressure profile,ECD profile and risk registericons.Figure 7—3D visualization during 97/8؆casing running 8Forecasting during Operations;Simulations aheadDue to large uncertainties in the pre-drill phase,various scenarios with various probability were simulated in advance in order to be prepared for all eventualities.Forecasting and pre-simulations was done based on 24hours ahead of operations,simulations of the next operation and Љwhat if Љsimulations when it was applicable.The result and suggestion was included to the daily report to the Operator.Overall,28pre-simulations were performed and evaluated.22simulations were about the integrity of Pressure profile during different operations like drilling,POOH,RIH,Liner running and Cementing.3ЉKick Tolerance Љsimulations and 3ЉWhat If Љsimulations were done ad-hoc to assist the operations team make the best possible desicion.3simulations were executed to find the optimum velocity of running 97/8Љcasing according to Kvitnos &Nise formations low FG pressure.During operation the Kvitnos &Nise formations were estimated to have a significant lower FG since limestone beds were present in the off set wells.Therefore,an evaluation had to be done to estimate the maximum allowed pressure in these formations.After reviwing the data,an agreement was made to set the maximum value in these formations equal to 1.89sg.Based on the simulations performed,the maximum running speed for the 97/8Љcasing inside the casing was 10m/min.Once the 97/8Љcasing was in open hole,the maximum running speed was 5m/min.During the actual casing job using the running speeds given,the calculated ECD in Kvinos &Nise formations was observed to reach the threshold value 1.89sg.One of the simulations is shown below in Figure 8.Figure 8—Running the casing with 10m/min inside casing &5m/min in open hole.As casing velocity is reduced to 10m/min inside the casing and 5/min in open hole the Nise/Kvitnos ECD is below the reference line.910Communications between Operation Team and Simulation TeamDue to that the decentralization of the Simulation team,proper and efficient communication was a key element during operations.The aim was to focus on the delivery and produce an effective workflow where all parties involved had a face to face communication during the day.Mail and phone dialogues were automatically restricted to avoid confusion and interruption between the teams.However,use of phone and mail was an option whenever one of the teams needed to get information across in due time.The golden rule in the communication given by Wintershall was aЉYou tell meЉphilosophy.The philosophy challenged all parties to actively think and assess the potential risk ahead in time.It also contributed to generate a cross company ownership,avoiding top-down communication,actively stimu-lating proactive thinking,strategy evaluation and involvement.The operations team demonstrated a short route from discussion of well specific challenges to final decision making.This implied that all relevant information and data gathered had to be evenly distributed to the involved parties,in order to ensure effective and constructive involvment.Even though the teams were sitting apart,the small organization involved,lead to an active collaboration in order to find the best optimum solution.In order to achieve the above,a focal point was established and maintained throughout the operation. At the same time,two daily meetings were agreed.The first meeting was a meeting between the focal points agreeing on the simulated values provided and the operational advices was debated.The meeting focused on the hydraulics,monitoring and drilling practice,along with the updated risk register data and prioritizing the risk elements for the future operation.This meeting was an add-on to the existing work process.The second meeting was between the Wintershall operations team with the rig supervisors and service partners,where the simulation team was represented with the focal point.The purpose of this meeting for the simulation team was to ensure all relevant data was captured from the rig.In particular this was data concerning operational constraints for the rig,viewpoints on the mud weight strategy and the upcoming operational risks as the rig saw it.This meeting was already a part of the work process and therefore it did not create any additional burdon on the operations team.One very important element into making this a success was that the Wintershall operations team put a lot of trust and empowerment into the Simulation team.The Simulation team was expected to make their recommendations towards the operation and focus onthe important boundary conditions downhole.This gave the Simulation team the flexibility to search and explore the different alternatives regarding the downhole environment and the operational steps in order to find and suggest the optimum path based on our populated data.This also ensured that the Simulation team actively investigated and challenged the PPFG values,as these were of extreme importance to the overall operation.This work created an independent verification of the risk picture and the assosciated risks moving forward.Summary of ResultsThe simulations and support collaboration gave the Wintershall team a clear picture of the operating window during well construction.During the construction the transient temperture effects were of significance and therefore the modelling system with real time updated temperature and resulting ECD modelling was very useful in illustrating the actual operating window.The results of this lead to a flawless133/8Љand97/8Љcasing running and cementing job,where all objectives were met,and allowed the well to be abandoned without any lost time.Some offset wells have historically spent significant time drilling the lower part of the12¼Љsection to TD,and experienced losses or Wellbore Breathing.Neither was experienced here during any phase of the well construction leading to a flawless P&A phase.This was achieved due to strict ECD management respecting the well limitations in all phases,spesifically in Nise and Kvitnos formations.This became hardto achieve during drilling of the lower part of the 12¼Љsection since the PP increased rapidly compared to the pre-drill model.The information displayed by the risk register allowed the team to actively assess and monitor the well limitations by real time data and look ahead simulations.During the casing running and cementing of the 97/8Љcasing,parameters were optimized as a direct result of the look ahead simulations performed.The running speeds were optimized and the cementing programs were altered in order to stay within the wells limitations.Ref:10ConclusionsUse of a life cycle simulation system generated a platform throughout the well delivery process,from planning to construction.This involved training and cross discipline collaboration,capturing the actual results compared to the pre-modelled assumptions;and this assured that the associated risks were controlled and managed.Open and constructive communication with clearly defined roles and responsibilities between parties was a key element in the successful delivery of the service provided.In order for Wintershall to achieve the overall goal to deliver a well on time and within budget,it was of importance to connect to a partner where the Wintershall team could seek advice on interrelated ECD management problems,solutions and related drillingpractices.1112AbbrevationsLCDSS:Life Cycle Drilling Simulation SystemECD:Equivalent Circulating DensityESD:Equivalent Static DensityEMW:Equivalent Mud WeightSPP:Stand Pipe PressurePPFG:Pore Pressure&Fracture GradientPOOH:Pull Out Of HoleRIH:Run Into HolePVT:Pressure-Volume-TemperatureHPHT:High Pressure High TemperatureBHAP&A:Plug&AbandonmentRPM:Rotations Per MinuteWOW:Wait On WeatherReferences1.Petersen,J.,Rommetveit,R.,Bjørkevoll,K.S,Frøyen,J.,ЉA General Dynamic Model for Single and Multi-phaseFlow Operations during Drilling,Completion,Well Control and InterventionЉ,SPE114688,IADC/SPE Asia Pacific Drilling Technology Conference and Exhibition,Jakarta,Indonesia,August25-27,20082.Xiaojun He andÅge Kyllingstad;SPE25370;SPE Drilling&Completion,March1995,pp.10–153.C.A.Johancsik et al.SPE11380,Journal of Petroleum Technology(1984),p.987–992.4.Xiaojun He,George,W.Halsey andÅge Kyllingstad;SPE30521;SPE Annual Technical Conference&Exhibition,22-25October1995.5.Knut,S.Bjørkevoll,Dag Ove Molde,Rolv Rommetveit,and Svein Syltøy:ЉMPD Operation Solved DrillingChallenges in a Severely Depleted HP/HT ReservoirЉ,SPE112739,SPE/IADC Drilling Conference,Orlando,Florida, 4-6March2008.6.Knut S Bjørkevoll,Svein Hovland,Ingvill,B.Aas and Alfrid,E.Vollen;ЉSuccessful Use of Real Time Dynamic FlowModelling to Control a Very Challenging Managed Pressure Drilling Operation in the North SeaЉ,SPE/IADC115118, SPE/IADC Managed Pressure Drilling and UB Operations Conference&Exhibition,24-25February2010,Kuala Lumpur Malaysia.7.Rolv Rommetveit,Knut,S.Bjørkevoll,Sven IngeØdegård,Mike Herbert,and George,W.Halsey.ЉAutomaticReal-Time Drilling Supervision,Simulation,3D Visualization and Diagnosis on EkofiskЉIADC/SPE112533.IADC/SPE Drilling Conference,Orlando,Florida,4-6March2008.8.Rommetveit,R,Ødegård,S.I.,Nordstrand,C.;Bjørkevoll,K.S.,Cerasi,P.,Helset,H.M.,Li,L.,Fjeldheim,M.andHåvardstein,S.T.,ЉReal Time Integration of ECD,Temperature,Well Stability and Geo/Pore Pressure Simulations during drilling a challenging HPHT wellЉ,SPE127809,SPE Intelligent Energy Conference and Exhibition held in Utrecht,The Netherlands,23–25March2010.9.Harald Blikra,Giancarlo Pia,Just Sverre Wessel,Morten Svendsen,Rolv Rommetveit and Sven IngeØdegård:ЉTheOperational Benefit of Testing HPHT/MPD Procedures Using an Advanced Full Scale Drilling SimulatorЉ;paper IADC/SPE167958presented at the SPE/IADC Drilling Conference and Exhibition held in Fort Worth,Texas,USA, 4–6March2014.10.Josef Nabavi,Rolv Rommetveit,Just Sverre Wessel and Laurie Scott;ЉA challenging HPHT Operation Supported byDynamic Real Time Simulation,Forecasting and3D VisualizationЉ.Paper IADC/SPE178857to be presented at the IADC/SPE Drilling Conference and Exhibition held in Fort Worth,Texas,USA,1–3March2016.。