an innovative and collaborative real-time well path planning,

An Innovative and Collaborative Real-Time Well Path Planning, Risk Analysis, and Update Workflow in Petrel

Author:Adrian Kemp, Drilling Software Solutions Marketing Manager, Schlumberger Information Solutions

Introduction

Cost reduction is a driving force in the development of brownfieldwells.1 It is well known that better planning leads to betterexecution in the drilling phase with less nonproductive time andreduced costs. This paper describes enhanced well planningworkflows in light of recent software technological innovations.The technology, which enables this solution for the first time in the industry, involves the addition of modules to Petrel seismic-to-simulation workflow software that are relevant to the drillingdomain, combined with innovative drilling applications such asOsprey* Risk drilling risk prediction software and drilling industrystandards such as Drilling Office* integrated engineering software.This workflow provides a means for closer collaboration betweendomains and rapid updating of plans and models, while mitigatingrisks and therefore reducing costs.

Abstract

Oil and gas companies developing and maintaining brownfieldsneed to constantly focus on cost reduction to maintain profitabilityand maximize the production life of their fields. The workflowsthat geoscientists and drilling and production engineers follow to plan wells and sidetracks in this setting are facilitated byadvanced software solutions. By adding the drillers’ world to the Petrel* seismic-to-simulation application, a step change in the planning and execution of brownfield wells becomes possiblefor the first time in the industry.

This paper discusses several radically new enhancements thatwill both enable a whole-process solution and extend it to real-time planning updates. Technical risks and probabilistic costs,which are a key part of the balance equation upon whichmanagement bases its “go” or “no-go” decisions, are nowavailable in the solution. 3D visualization enhancement enablesgeoscientists to obtain cost estimates for proposals more quickly and allows drilling engineers to obtain feasible welldesigns faster, while providing a collaborative common view for confirming understanding and enhancing technical decision making.

*Mark of SchlumbergerInteractive Petrophysics is a trademark of Production Geoscience Ltd.Copyright © 2007 Schlumberger. All rights reserved.

Shared earth model component

The shared earth model (Fig.1) is conventionally used to combine the models of reservoir engineers, geophysicists, and petroleum geologists to simulate a reservoir. Reservoirengineers, geophysicists, and petroleum geologists separatelysimulate properties of the reservoir, which vary depending on thetechnology used by each geoscientist or engineer.2 The conceptof shared earth modeling for use in drilling can be extended intothe overburden, so the subsurface zones are included where the bulk of the drilling work is done. The simulations for this purposeshould include structural geology, formation markers, pressures,rock strength, earth stress information (where available), andrecords of trouble zones.

The enhanced model will allow geoscientists and drillingengineers to consolidate their results and create an integratedsimulation from surface to bottom of the reservoir. This willprovide a more realistic view of what the earth looks likephysically and operationally, thereby saving unnecessary drillingcosts, improving the quality of the wells delivered (and thereforeenhancing production), and—through collaboration—reducingthe time required to obtain an integrated subsurface model.


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Figure 1. Concept of shared earth model extended from surface to below the base reservoir.

G&GREPE

Offsetwells

Scoperisk

Detailedengineering

Drillingoperations

Lessonslearned

Actualvs.

plan

Finalwell

report

Key historicinformation

EvaluationExecution—Real-Time Monitoring—ReplanningPlanningShared Earth Model

G&G = Geology and geophysics RE = Reservoir engineering PE = Production engineering OSC = Operation Support Center TD = Total depth

Replan

TD

Petrel (shared earth model)

Interactive Petrophysics (geomechanics)

Osprey Operations Manager

(performance analysis)

Osprey Risk (screening and scoping)

Drilling Office,TDAS

(engineering)

OSC (real-time

collaboration)Petrel

(model updating and risk management)

Osprey Risk(updating while drilling)

Osprey Operations

Manager(knowledge

sharing)

Osprey Reports

(operations tracking)

Osprey Operations

Manager(operations surveillance)

The shared earth model is the basis for the collaborative wellplanning workflow (Fig. 2). In this model, geoscientists use PetrelWell Path Design to provide target definitions for the subsurfacelocations from which the reservoir should be drained. Locationsmay require new wells or sidetracks from existing wells (capitalworkovers) to be drilled. The shared earth model providesprofiles with depth of pore pressure and rock fracture strength,which may originate from well correlations or be simulated usingreservoir analysis software such as Interactive Petrophysics™.

In brownfields, good records generally exist in the database fordrill bit performance. These can be easily transformed into aprofile with the depth of a relevant strength parameter, which can be used to select drill bits in the new well or sidetrack. These inputs, together with the deviation profile from the Petrelapplication and a description of well objectives, are used by thedrilling engineer for conceptual design or scoping in Osprey Risk.The outputs include rig selection, drilling engineering technicalrisk, and probabilistic time and cost estimates.


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Figure 2. Real-time well path planning, risk analysis, and update workflow (top) with technology map (bottom).

Options exist to map the outputs of gains or losses, stuck pipe, ormechanical failure risks back into the Petrel solution. These riskscan be upscaled and added to the shared earth model for use infuture well planning.

A pilot study was conducted on a major oil company’s deviatedland well in the Deep Foothills to apply the workflow, assess thevalue of early prediction of the risks involved, and estimate therisk exposure and probabilistic time and cost. The model for thesubject well was constructed from six offset wells. These resultswere then compared with the actual well data to determine thepotential value of the integrated solution. Simulated costs wereCAD 2 million less than actual, and simulated rig-move to rig-movetime was 15 days less than actual.

In parallel, the Petrel deviation profile can be loaded into theDrilling Office application, which is capable of calculating thedetails of well-to-well proximity within the population of offsetwells to the highest levels of technical integrity using industry-standard modeling. The offset wells and a planned well can beviewed with their cones of uncertainty, derived from survey toolmeasurement errors and environmental factors, so that true well-to-well distances can be assessed in a probabilistic way.Key technical indicators such as the separation factor arereportable for anti-collision design and form part of a morecomprehensive technical proposal document assembled within the system. This system also delivers detailed analysis of engineering issues that may have been highlighted by thetechnical risk profile obtained from Osprey Risk. The DrillingOffice application is capable of designing BHA and analyzingdrillstring hydraulics and string-to-borehole frictional interactionssuch as torque, drag, and BHA vibration, which may not all becovered in Osprey Risk to the same level of detail. If required bythe technical risk profile or for technical integrity reasons, otherengineering tools are available to provide a more advanceddeviation profile; this makes it possible to design or analyzetubular strings such as casing, liners, and completions (TDAS*Tubular Design and Analysis System software). Results of thetubular string design can be summarized and viewed in theshared earth model using the Petrel application.

Petrel technology is also capable of automating repetitive tasksin a coherent workflow. An experienced drilling engineer createsthe record of the Petrel workflow steps and shares it with theteam. Other authorized staff members can follow these guidelines

using the input of their specific data to produce a standardizedoutput. Supervisors checking the results are assured that thecorrect process has been followed.

Well plans are used frequently as input into the economicevaluation of projects. The production forecast from Petrelreservoir engineering for the proposed well, combined with theprobabilistic well cost, can provide quick answers regarding theadded value of the well. In addition, well plan options can becompared in less time by orders of magnitude.

Real-time component

This solution enables users and managers to follow the executionof drilling operations within the geoscience model used forplanning the work. The latest implementation of Petrel softwareprovides a real-time data link that allows Wellsite InformationTransfer Standard Markup Language (WITSML) data from anysource to be displayed for deviation surveys and risks. Thisallows more geoscientists and drilling engineers to witness therig operations from their petrotechnical desktops. The DrillingVisualization module in the Petrel application provides a means of capturing risks and correlating them from well-to-well markersfor better consistency, by enabling them to be visualized in the 3Dcanvas as a zone so that they can be used to avoid trouble spotsin future planning (Fig. 3).


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Figure 3. Screenshot of several typical drilling risks in Petrel.

An immediate cost- and time-saving implementation is providedby the Operation Support Center (OSC). During the executionphase of the workflow, it is advantageous in brownfielddevelopment to minimize the number of personnel on the rig toboth save costs and reduce unnecessary exposure to safetyhazards. This is feasible if technical expertise is availablecentrally and a telecommunications infrastructure is provided tolink the data from the rig to the center using the OSC.3 The OSC isa collaboration space both physically and in terms of informationsharing. It can be provided with key technical models, both forhydraulics and for torque and drag, which are shared with a real-time monitoring service solution; and it is able to detect rigoperating states such as drilling or tripping and calculate them in context so that alarms can be set for deviations from norms.The real-time deviation measurements from the borehole drilledand LWD outputs can be displayed simultaneously in the OSCsoftware and in the shared earth model in the Petrel application.This allows the team to confirm plan compliance and makedecisions at technical milestones such as casing points.4 Byviewing execution information in the plan, a register of incidentssuch as losses or stuck pipe can be made and future plans cantake into account these trouble zones in the offset wells. Thisboth improves future planning and permits replanning at shortnotice in the case of unexpected issues, such as a mechanical or geological sidetrack. Here again the Osprey Risk time, cost,and risk simulation application is excellent with its ease of useand fast, repeatable conceptual design capability.

If desired, the basis for design can be updated with actualparameters and the Drilling Office suite can generate a technicalanalysis for the end-of-well report. Finally, the OSC software can be used to play back the drilling history (drilling parameters,BHAs, and subsurface LWD) so that lessons can be learned fromdrilling issues in the well or sidetrack.

Advantages of the collaborative planning workflow

The collaborative planning workflow has the followingadvantages.

• Geologists and drillers work more closely, avoidinginterpretation and planning silos.

• Wellsite geologists can remain in the office to supervise critical operations.

• 3D graphics for drilling operations provide a betterunderstanding of spatial relationships between wells andgeobodies, enhancing collaborative decision making.

• Geosteering within thin beds is easier with real-time deepimaging.5

• Drilling planning is more tightly integrated with execution.

• Interpreting the shared earth model from 3D seismic provides a solution for overburden modeling.

• Individual experts can interpret real-time data from theirpetrotechnical desktops, as well as from OSCs.

Key features

• The interactive geological model is key for geosteering.

• The technical risk evaluation is key for feasibility assessment.

• A facies model in the geoscientists’ system allows synthesis ofthe pore pressure and fracture gradient from 3D seismic.6

• Rapid geomechanics risk prediction reduces drilling risk andallows rapid evaluation of multiple possible well plans.7

Adding the drillers’ world to Petrel technology shows thesimulated technical risks in the shared earth model, while addingthe records of actual incidents or trouble zones and making themavailable for correlation and visualization in a system used to picktargets or plan trajectories. In addition, at the time of executionthe Petrel Real-Time Data Link provides the ability to replan whiledrilling, as well as to witness operations or update correlationswithin the shared earth model.


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Challenges and organizational barriers to collaboration

Organizationally, E&P operator divisions may not be optimized forcollaboration across disciplines. Barriers may be present thatlimit the effectiveness and reduce the potential of the newworkflow. These must be overcome to realize the full potential.

One challenge in an E&P organization is to overcome resistanceto change; 3D graphics are not used universally in brownfielddrilling engineering. Today’s drilling engineering is report- and 2Dgraph-based. Innovative use of inserts and color-coded technicalparameters (such as dogleg severity) in 3D models can overcomemuch initial resistance, particularly when the system is coupledwith advanced drilling engineering tools and does not replace butrather enhances those reports and 2D graphics.

Future directions

As the system evolves, it will be possible to save resultsgenerated in the 3D interface back into the engineering tools.More results will be shared and visualized, and automation andrecording of the process will become easier for the drillingengineering community. Overburden models will become morecommon and be of better quality. Automated structuralinterpretation or “ant tracking” will promote productivity instructural modeling, and picking faults and other advances willhelp geoscientists adapt their work priorities to spend sufficienttime on this key aspect of the shared earth model.

Extensions will include operations data reporting so that risksfrom the operations report can be visualized and correlated in the shared earth model. Smarter platform placement will becomeavailable by defining antitargets (no-go areas), and platforms will be placed by least cost, least time, or least risk. Geosteeringworkflow tools such as forward log prediction systems willbecome more readily available, and it will be possible toincorporate multiple realizations of the geological model so thatgeosteering in uncertainty areas is easier. Shared earth modelswill be updated while drilling, and will include simulation whiledrilling8 for optimum reservoir drainage.

Conclusions

This well planning solution combines technical risk profiles andreal-time connectivity with 3D visualization in a collaborativegeoscience interpretation and modeling environment. Previoussolutions were incapable of providing this level of technicalcapability with repeatability and knowledge sharing, having eithertoo little geoscience capability or no technical risk profiles. Thetechnology is capable of evolving further as it gains acceptance.The work experience of both geoscientists and drilling engineerswill make it attractive to work collaboratively, with the sharedearth model as an integral part of the workflow for bothdisciplines.

The solution has the following primary benefits:

• Geologists and drilling engineers can work more closelytogether, with wellsite geologists able to supervise from theoffice if necessary.

• The movement of expertise from the wellsite to the officeor to an OSC has other benefits, such as increased safety,a reduced logistics burden, and more efficient use ofhuman resources.

• Experts can connect from their own petrotechnicaldesktops to witness drilling operations.

• The evolution of 3D graphics used in geoscienceworkflows for drilling operations, provides clarity about thespatial relationships between wells, and between wellsand geobodies.

• The Petrel application is easy to use; the tighter integrationof drilling planning with execution allows rapid planningand replanning. The use of the Osprey Risk drilling riskassessment software provides a fast, accurate assessmentof drilling cost and risk.

• In a nutshell, the addition of the drillers’ world to the Petrelapplication provides a game-changing solution for today’soilfield—with the ability to evolve to meet the challenges of tomorrow.


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Technology enablers

Schlumberger software athttp://www.slb.com/content/services/software/index.asp?

Schlumberger drilling software athttp://www.slb.com/content/services/drilling/rtd/index.asp?

• Drilling Office integrated drilling software

• Interactive Petrophysics log analysis software

• Operation Support Center (OSC) real-time drilling collaboration solution

• Osprey Operations Manager operations surveillance andperformance analysis system

• Osprey Reports well operations reporting software

• Osprey Risk drilling risk assessment software

• Petrel Drilling Visualization risk management module

• Petrel Real-Time Data Link module (included in Petrel 2007 core)for streaming and static real-time data

• Petrel Well Path Design trajectory planning module

• TDAS Tubular Design and Analysis System software

References

1. Spath, J.: “Optimization revitalizes brownfields,” Hart’s E&P(December 2004).

2. Fanchi, J.R.: Shared Earth Modeling, Butterworth-Heinemann(2002).

3. “Case study: Operation Support Center drilling optimizationsaves Helis more than USD 1.7 million on Gulf of Mexico well,”http://www.slb.com/content/services/resources/casestudies/drilling/osc_gom_helis.asp.

4. “Enhance precision geosteering and decision making withreal-time 3D modeling using Petrel workflow tools,”http://www.slb.com/media/services/software/geo/petrel/petrel_realtime_geosteering.pdf?

5. “Case study: Production enhanced by placing more than 1,300 m[4,265 ft] of Middle East well in thin reservoir with uncertain dip,”http://www.slb.com/content/services/resources/casestudies/drilling/periscope_middle_east.asp.

6. Sayers, C., den Boer L., Nagy Z., Hooyman P., Ward V., “Pore pressure in the Gulf of Mexico: Seeing ahead of the bit,”World Oil (October 2005).

7. Nagy Z., Elisabeth F. and Sayers C., Schlumberger; Valleau D.,and Berkovski L., Burlington Resources, “Understanding thegeomechanics risk,” Hart’s E&P (October 2005).

8. Bourgeois D., Tribe I., Christensen R., Durbin P., Kumar S.,Skinner G., and Wharton D., “Improving Well Placement withModeling While Drilling,” Oilfield Review, Volume 18, Number 4(Winter 2006/2007).


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