a_system_for_real_time_drilling_simulation_3d_visualization_and_control-good

This paper was prepared for presentation at the 2007 SPE Digital Energy Conference and Exhibition held in Houston, Texas, U.S.A., 11–12 April 2007.

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Abstract

eDrilling is a new and innovative system for real time drilling

simulation, 3D visualization and control from a remote drilling

expert centre. The concept uses all available real time drilling

data (surface and downhole) in combination with real time

modelling to monitor and optimize the drilling process. This

information is used to visualize the wellbore in 3D in real

time. The system is composed of the following elements, some

of which are unique and ground-breaking:

? An advanced and fast Integrated Drilling Simulator which

is capable to model the different drilling sub-processes

dynamically, and also the interaction between these sub-processes in real time. The Integrated Drilling Simulator is used for automatic forward-looking during drilling, and can be used for what-if evaluations as well. ? Automatic quality check and corrections of drilling data; making them suitable for processing by computer models. ? Real time supervision methodology for the drilling

process using time based drilling data as well as drilling models / the integrated drilling simulator. ? Methodology for diagnosis of the drilling state and conditions. This is obtained from comparing model predictions with measured data.

? Advisory technology for more optimal drilling. A Virtual Wellbore, with advanced visualization of the downhole process. A new generation visualization system designed to integrate all participants involved, will enable

enhanced collaboration ? of all drilling and well activities in

Data flow and computer infrastructure.

people coming into the

industry; the “game boy generation”.

a global environment.

The combination of the various elements will make e-Drilling very attractive to the new e-Drilling has been implemented in an Onshore Drilling Center in Norway. This paper will present the e-Drilling

system as well as experiences from its use.

SPE 106903

eDrilling: A System for Real-Time Drilling Simulation, 3D Visualization and Control

Rolv Rommetveit, SPE, Knut S. Bj?rkevoll, SPE, George W. Halsey, SPE, Erling Fj?r, SINTEF Petroleum Research;

Sven Inge ?deg?rd, Hitec Products Drilling; Mike Herbert, SPE, ConocoPhillips; Ove Sandve, First Interactive; and Bjarne Larsen, Aker Kvaerner Maritime Hydraulics Introduction A new generation real time simulation and visualization system designed to integrate all participants involved, will enable enhanced collaboration of all drilling and well activities in a global environment; see Ref. 1. The system is designed on an open 3-D visualization motor that can visualize all drilling and well related operations involved. The system is based on an open system architecture where equipment suppliers, service companies, contractors, and operators can connect to via standard interfaces (i.e. WITSML etc.). The system is designed to handle the expected high data rates as a result of the use of wired pipe and similar technologies. Results related to drilling. Costly failures will be reduced and better knowledge of the process will be obtained:

? T he driller/directional driller will see if the bit follows the planned well path. ? Geologists/drilling engineers will be able to see the

bit going through different geology layers in real time. ? Petro-physicists can see the bit entering seismic

information layers real time (not finished, in

progress). ? Accurate depth by visualizing the tally/BHA in real time. ? Enabling to see the bit or tool joint going through

restricted areas like the BOP or Casing shoe. ? Link real time software models with real time data

to analyze and optimize drilling performance. E.g. visualize well pressure profile and prediction of

pressure when drilling ahead. ? Backtracking of operations in 3D (similar to REW

& FWD on a tape recorder).

? The system is well suited for training and competence building.

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Fig.1: Typical

eDrilling

infrastructure

Models for Real Time Drilling Analysis

eDrilling will provide the technology elements to realize real time modeling, supervision, optimization, diagnostics, visualization, and control of the drilling process from a remote drilling expert center. These technology elements are:

?An advanced and fast integrated drilling simulator which is capable to model the different drilling sub-

processes dynamically, and also the interaction

between these sub-processes in real time.

?Data Quality Module DQM.

?Real time supervision methodology for the drilling process using time based drilling data as well as

drilling models / the integrated drilling simulator.

?Methodology for diagnosis of the drilling state and conditions.

?Advisory technology for more optimal drilling.

? A Virtual Wellbore, with advanced visualization of the downhole process.

?Data flow and computer infrastructure.

Data quality module

Correct processing and interpretation of the data that are acquired in the drilling process is essential for safe and efficient operation as well as efficient and reliable interpretation and analysis. Today, measured data are often disturbed by physical effects that can lead to faulty interpretation. By systematic modeling of physical effects that influence the measured values, improved drilling data will be obtained for important drilling parameters. In addition to the error correction, algorithms will also be developed for identification of the proper state of the drilling process (drilling, tripping, circulation, make connection or reaming).

Advanced filtering techniques are required to extract as much information as possible from drilling data. This module therefore addresses:

?Calculation of important physical parameters from available raw data, e.g. calculation of hook load and

surface torque.

?Determination of drilling status, e.g. whether bit is on or off bottom, and whether drillstring is in slips.

?Detection and handling of sensor failure.

?Correction of systematic errors and noise.

?Removal of erroneous or misleading data that are not handled otherwise.

Real time models

The models that form the background of the real time models are the result of accumulated knowledge from continuous

R&D and modeling in drilling. This knowledge is assembled

in an Integrated Drilling Simulator. Models with the appropriate degree of complexity have been selected, and the models have been improved where it has been seen as necessary, and re-implemented using methods that are optimized with respect to challenges in real time applications.

The model basis for the transient and steady state applications has been built with focus on:

?Accurate representation of the physical system.

?Flexibility.

?Requirements related to real time applications:

o High degree of robustness, also when driven

by real time data like pump rate, rate of

penetration, drillstring rotation rate, torque,

and inlet temperature.

o Sufficient calculation speed under relevant

conditions.

The following building blocks are established: Flow/hydraulics including temperature, torque/drag, vibrations, rate of penetration (ROP), wellbore stability, and pore pressure. Some of these models will interact with the mechanical earth model (MEM) as well as with each other.

Fig.2: Sketch of how different sub-models interact in the

Integrated Drilling Simulator.

SPE 106903 3

Some of the elements of the integrated drilling simulator are described in detail below.

Downhole pressure and flow. An advanced transient flow and temperature model is being built. The model will handle calculation of

?Pressure/ECD, temperature, and pit volume vs. time while drilling and circulating, including flow of

cuttings.

?Transient well pressure and flow vs. time during

surge and swab; handling details of individual stands

as well as and tripping the whole string in or out.

?Equivalent Static Density and temperature vs. time during static periods, e.g. flow tests.

?Transient pressure and flow vs. time while resuming circulation after static periods.

The model includes state of art sub-models for frictional pressure loss and fluid density. Pressure and temperature dependence of fluid properties can be taken into account through the input of laboratory data (rheology, density, thermal properties), or by using published correlations on fluid density.

When developing the new model special focus was put on the adaptation to a real time environment. A modular and flexible design was used to easily adapt to different topologies, and to make the algorithms fast and robust.

A few key parameters are selected for tuning of the model during real time operation.

The model will be calibrated to incorporate effects of slowly drifting model parameters, but still give warnings when relatively rapid significant changes relative to model prediction are observed.

The flow model has been extended to multi-phase flow, to be used for e.g. well control operations and underbalanced drilling.

The model has been used in design, procedure development and also for real time optimization and follow-up of critical operations (Refs. 2, 3, 4, 5). Details of the flow model are given in Ref. 6.

Torque/drag. An advanced torque/drag model has been built. The model will be applied for the calculation types:

?Calculate WOB with input of hook load or vice versa.

?Calculate bit torque with input of surface torque or vice versa.

?Back-calculation of friction factor with input of measured surface and bottom hole weights or torques.

Friction factor can be monitored with warnings issued

on unexpected changes.

?Bit depth correction due to string elasticity. More accurate bit depth will increase value of LWD.

?Initial calibration of rig specific parameters, such as model parameters for force/torque transfer from top

drive system to string.

Benefits are realized through

?Comparing measured hook load with calculations while tripping, and warn if unexpected deviations

occur. Compare with earlier trips to identify expected

effects like dog-legs.

?Comparing measured and calculated hook load and torque during connection tests, which typically

involves pick up, rotating off bottom, and slack off.

Trends in data and calculations are used to obtain

early indications on poor hole cleaning.

?Comparing measured torque and ROP while drilling with calculated results to get early indications on

poor hole cleaning. Both the torque/drag model and

the bit/ROP model will be involved.

Drilling vibrations. Algorithms are implemented to help detect drillstring vibrational problems. When such problems are detected, solutions will be recommended. Recommendations might include active damping, such as the algorithm developed to cure stick-slip motion of the drillstring, or adjustments to the drilling parameters weight on

bit or rotary speed. The algorithms concentrate on the detection and cure of vibrations, not on the prediction of vibrations. The algorithms chould be combined with predictive algorithms for planning a wellpath and BHA design to help avoid drilling vibrations.

Rate of Penetration ROP. While drilling a well, the rate of penetration will vary. Some of this variation is due to variations in the formation parameters and some is due to variation in the drilling parameters. The important formation parameters are the compressive strength and the formation pressure. Drilling parameters include a description of the bit, the weight on bit, the rotary speed, the borehole pressure, the mud flow rate and viscosity. Analysis of these variations, intentional or incidental, can give more information on conditions downhole than is generally assumed possible. Time-based logging data is a prerequisite for this analysis.

Figure 3 represents a snapshot of the ROP analysis based on data from ConocoPhillips. Analysis of this data revealed that by adjusting the WOB to give the maximum ROP, drilling time could be reduced by 15%. Further, it was concluded that

if we could totally remove the vibration related problems, drilling time could be reduced by over 40%.

The analysis of the ROP will be performed simultaneously with analysis of (1) torque on bit/weight on bit relationship, (2) torque and drag analysis, (3) monitoring of hole cleaning, and (4) well pressure, but the main focus will be on ROP.

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Fig.3:

Map of ROP versus WOB with Vibration Effects

Wellbore stability. The mechanical stability of the rock around the borehole can be evaluated by a borehole stability simulator. The output from this module will be an estimate of the probability of well bore instability based on formation description and the temperature and pressure history along the well path. Details on the wellbore stability models are given in Refs. 7 and 8.

The stability simulator checks whether the criteria for shear or tensile failure are fulfilled or not, at a series of points around the hole. Effects related to mud chemistry, hole deviation, in situ stress anisotropy, temperature, rock plasticity, and anisotropic formation strength are all included and accounted for with varying degree of precision. The calculations are largely based on approximate analytical expressions, hence the simulator works quickly, and may be used efficiently to test the impact of variations in the input parameters – for instance the impact of chemical additives in the mud, or different hole orientations.

Based on these calculations, the stability of the hole as a function of mudweight and time since drilling may be estimated. At a specified time since drilling, the simulator provides estimates of the probability for failure (Fig. 4).

Fig.4:

Probablity for failure versus mudweight.

The mudweight window may be defined as the range where the probability for failure is less than 0.5. The simulator may then provide estimates of how the mudweight window changes with time, as illustrated in Fig. 5. In the example given here, the mudweight window is seen to shrink with time, indicating that the probability for wellbore stability problems is increasing significantly if the hole is left open for several days after drilling.

The simulator may also be used to analyze the conditions around the well in more detail. This allows for a more operationally oriented output, in terms of probability for collapse, probability for mud loss etc., which will be implemented later.

The current version of the simulator is based on the assumption that the well pressure remains constant since the time of drilling. Work is in progress to couple the transient flow and thermal well model with the stability simulator, so that the coupled flow & stability model eventually will be able to include variations in well pressure & temperatures while still maintaining the already existing features of the model.

Fig.5:

Hole stability versus time since drilling

SPE 106903 5

Pore Pressure. The multi-purpose geo-pressure modelling tool PRESSIM includes all significant processes relevant to pressure generation and dissipation. This model is coupled to the integrated drilling simulator. For more details on PRESSIM see Ref. 9.

Process & operation module. The integrated drilling simulator is driven by the drilling data, and computed results are compared with measured values to generate an initial diagnosis. Trend curves of measured drilling parameters versus calculated will be used to visualize the drilling history. The process and operational related modules will use results from the basic process models to discover upcoming problems as early as possible, and to further analyze the drilling data when problems are suspected. These will run in the background and give input to the active process and operational related modules during the various drilling phases.

Diagnosis. Various specific process and operational related modules have been built on top of the basic process models for interpretation and diagnosis purposes.

Forward Looking. Automatic forward-looking is performed by the calibrated models by projecting the drilling process a given time period ahead.

Data Flow and Computer Infrastructure

There will be a considerable amount of data exchange between simulator-modules, visualization clients, control system and external data sources, and the characteristics of data will vary from “real-time”- and historical-data to operator input.

The figure below illustrates typical system architecture. Data from external sources is acquired by the data-collector and made available for the simulators and visualization-clients through the server. All communication between the simulators and the visualization-clients will also be performed trough the

server.

Fig.6: eDrilling system architecture

When joining the server, the client request for data to subscribe and gives information about update rate required, etc. Definition of output data for each client is loaded into the server from a XML-file, and data is published by the clients.

3D Visualization

The idea is to give the operator, support personnel, management or any one else who need to be updated with live data from the drilling process, a detailed, 3D real-time insight into the ongoing drilling operation.

The real-time 3D visualisation in eDrilling is a new generation advanced drilling/well visualisation tool, where the operator has 3D visual control of the entire drilling process through an easy-to-use interface. Though the system runs on a PC based platform, it is more than powerful enough to visualise structural data, equipment – topside, seafloor and down-hole, together with multiple real-time data sources.

The eDrilling 3D visualization tool can be used as an advanced information cockpit in a single PC setup, in a multi screen control room environment, or in a collaborative setting where multiple users, sitting at different locations, are connected via the Internet.

Below is an example showing a display combining a 2D view of the well showing the temperature profile with 3D information.

Fig.7:

Example display with combined 2D and 3D information

Results

The eDrilling system is now installed in the new operations center for the X and K teams on Ekofisk. This system will enable decision makers to have better insight into the status of the well and formation surrounding the well and thus make better and quicker decisions. This is of particular importance when problems or unusual situations arise and experts are called in to make decisions. They will quickly be able to grasp the situation and make the correct decision.

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Fig.8:

Screen shot from the virtual wellbore 3D

visualization tool.

Conclusions

The first version of the eDrilling system is now running on the Ekofisk Field. The combination of simulation and drilling analysis, interfacing; and 3D visualization has given a system which gives a continuous visualization and supervision of the drilling in real time. It provides automatic decision support for the personnel in charge.

The overall result is a more cost effective and safer drilling and well construction operation.

A CKNOWLEDGEMENTS

The authors would like to thank ConocoPhillips Norge and Norwegian Research Council Petromaks Program for the permission to publish this paper.

References

1. ?deg?rd, S.I., Rommetveit, R, Larsen, B., Paulsen, O., ”Future

drilling and well activities are globally integrated using 3D visualization”, presented at the Offshore Mediterranean Conference and Exhibition in Ravenna, Italy, March 16-18, 2005

2. Rommetveit, R., Fjelde, K.K., Fr?yen, J., Bj?rkevoll,K.S.,

Boyce, G. and Eck-Olsen, J.: “Use of Dynamic Modeling in Preparations for the Gullfaks C-5A Well”, SPE/IADC 91243, presented at the 2004 SPE/IADC Underbalanced Technology Conference and Exhibition held in Houston, Texas, U.S.A., 11–12 October 2004.

3. Eck-Olsen, J., Pettersen, P.J., R?nneberg, A., Bj?rkevoll, K.S.

and Rommetveit, R.: “Managing pressures during underbalanced cementing by choking the return flow; innovative design and operational modeling as well as operational lessons”, SPE/IADC 92568, presented at the 2005 SPE/IADC Drilling Conference in Amsterdam, The Netherlands, 23-25 February 2005.

4. Bj?rkevoll, K.S., Rommetveit, R., Eck-Olsen, J. and R?nneberg,

A.: “Innovative design, operational lessons learned for pressure management during underbalanced cementing with choked return flow”, Paper presented at the Offshore Mediterranean Conference and Exhibition in Ravenna, Italy, March 16-18, 2005

5. Bj?rkevoll, K. S., Rommetveit, R., R?nneberg, A., Larsen,

B., “Successful Field Use of Advanced Dynamic Models”, IADC/SPE 99075, IADC/SPE Drilling Conference, Miami, Florida, February, 2006

6. Petersen, J., Bj?rkevoll, K. S., Fr?yen, J., Rommetveit, R.:

“A general dynamic model for flow related operations during drilling, completion, well control and intervention”, IBP1373_06, presented at the Rio Oil & Gas Expo and Conference 2006, September 11-14 2006, in Rio de Janeiro.

7. Fj?r, E., Holt, R.M., Nes, O.-M. and S?nsteb?, E.F.,

2002:”Mud Chemistry Effects on Time-Delayed Borehole Stability Problems in Shales”. SPE/ISRM 78163.

8. Nes, O.-M., Fj?r, E., Tronvoll, J., Kristiansen, T.G. and

Horsrud, P., 2004:”Drilling Time Reduction through an Integrated Rock Mechanics Analysis”, SPE/IADC 92531 9. Borge, H., “Modelling generation and dissipation of

overpressure in sedimentary basins: an example from the Halten Terrace, offshore Norway”, Marine and Petroleum Geology 19 (2002) 377-388