drilling management

Certainly there is not a single JPT reader that has not already read and heard about the Macondo-well blowout in the Gulf of Mexico (GOM). Over the last few months, this accident has been present in almost every conversation about the oil industry. Many articles have been written, and many more certainly will be prepared and presented at future conferences. The subject has been present in the daily media around the world. In the SPE Drilling and Offshore Operations technical interest groups, several posts have generated heated discussions as well as a diverse array of propositions about how our industry should proceed from now on. So it seems natural that this JPT section dedicated to drilling manage-ment also should address the subject.

For those of us working in the GOM area, it is more than clear by now that this accident will change the industry forever; and not only in the GOM. Members of the industry, managers and technical experts alike, are taking this occasion to reassess operational procedures, equipment safety, and training needs to find opportunities for improvement that will make our operations safer and more efficient. A proficient drilling-management process is now more important than ever. This process must permeate all phases of a project, from early planning to final execution. Risk assessment of all operations must become a routine.

Last year, I wrote in this space about the importance of risk management for drilling and completion operations. I mentioned that there are many articles con-cerning successful projects in which risk analysis was a fundamental part of all operations. Now may be the right moment for all of us to follow those engaging examples. At the risk of being repetitive, I would like to conclude with exactly the same words that I used to close last year: “It is clear to me that drilling man-agement is related closely to risk management. The correct assessment of all risks involved in drilling operations will provide better planning and consequently will improve operational results.”

Drilling Management additional reading available at OnePetro: www.onepetro.org

SPE 128288 • “Drilling Efficiency and Rate of Penetration—Definitions, Influencing Factors, Relationships, and Value” by Graham Mensa-Wilmot, SPE, Chevron, et al.

SPE 128222 • “High Performance and Reliability for MPD Control System Ensured by Extensive Testing” by John-Morten Godhavn, SPE, Statoil, et al.

SPE 128871 • “Real-Time Drilling-Data Analysis: Building Blocks for the Definition of a Problem-Anticipation Methodology” by R.A. Gandelman, Petrobras, et al.

Drilling Management

TECHNOLOGY FOCUS

72 JPT • SEPTEMBER 2010

JPT

J.C. Cunha, SPE, is Well Operations Manager for Petrobras America in Houston. Previously, he was an Associate Professor of petroleum engineering at the University of Alberta, Canada. Cunha has served on several SPE committees and chaired the SPE Drilling Technical Interest Group, and currently is a 2010–11 SPE Distinguished Lecturer. He holds a civil engineering degree from Juiz de Fora Federal University, Brazil; an MS degree in petroleum engineer-ing from Ouro Preto University, Brazil; and a PhD degree in petroleum engi-neering from the University of Tulsa, USA. Cunha’s career spans engineering and management positions on several projects in South America, the Gulf of Mexico, Africa, and the Caribbean. He has authored various technical articles including 30 SPE papers. Cunha current-ly chairs the JPT Editorial Committee.

JPT • SEPTEMBER 2010 73

The full-length paper details the field-implementation experience of an in-house-developed system for drilling-problems detection and identifica-tion. Starting from real-time drilling data, the system was designed to investigate reasons for deviations in important measured variables (e.g., downhole and pumping pressures, temperatures, and torque and drag) during drilling operations. Based on a hybrid approach, including mul-tiphase-hydraulics and torque-and-drag modeling, case-history match-ing, and knowledge of specialists, the system should identify undesir-able events.

IntroductionDeep- and ultradeepwater exploratory drilling is a very risky and costly operation in which every effort to guarantee performance and opera-tional safety is welcome. Low fracture gradients, abnormal pressures, losses, and unstable formations are among the items that make well design com-plex and well construction a continu-ous challenge.

Several exploratory prospects cur-rently ongoing in Petrobras face very narrow operational windows, and well construction will demand unconven-tional techniques.The anticipation and remediation of potential hole prob-lems is an ultimate goal of most real-time measurement devices installed on drilling rigs. Much effort has been spent in downhole sensors and data-transmission systems, but there is a common sense in the industry that very little is available in real-time data interpretation. Pressure-while-drilling (PWD) data, for instance, is used in a subjective manner, and interpretation depends to a great extent on the phi-losophy of the operator.

Some preliminary implementa-tion efforts at rigsites and at onshore decision-support centers have dem-onstrated the potential of drilling-data-interpretation systems in reducing operational costs and risks.

In 2006, as a strategy to preserve the knowledge retained by experi-enced professionals and to achieve effective gains from real-time data, a development project was started to generate a drilling-interpretation sys-tem. Starting from a long-term experi-ence in developing steady-state and transient-hydraulics models, an initial development of a real-time hydraulics model for vertical wells to guarantee pressures inside the operational win-dow was proposed. Soon, the team understood that a reliable analysis would have to go beyond hydraulics. A multidisciplinary team, including software developers, data-communi-cation professionals, artificial-intelli-gence specialists, and petroleum engi-neers, was established to define the requirements and objectives for the system. The idea was to make full use of measurement-while-drilling/PWD and mud-logging data for analyzing

the drilling operation. Logging-while-drilling data would be considered in a further step because the company already had a team for real-time geo-pressure analysis.

PWD SystemThe goal was to establish quantitative criteria to interpret real-time data and to provide a tool to help the operators to make important decisions rapidly in an objective way, optimizing the drilling job (reducing time and opera-tional costs).

The methodology developed exists in several integrated modules that receive, simulate, and interpret all available data. PWD data, pump pressure, and torque and drag are predicted and compared with the real parameters. Differences between real and predicted curves indicate that some unexpected phenomenon may be happening. The different tendencies of real and pre-dicted curves are interpreted to identify potential problems. Once a problem is identified, the methodology proposes preventive and/or corrective actions to be taken.

Among the operational parameters available, the most important are the following.

• Bottomhole annular pressure• Bottomhole annular temperature• Pump pressure• Inlet and outlet flow rates• Drillstring rotation• Rate of penetration (ROP)• Torque• Drag• Hole depth (measured and vertical)• Bit depth (measured and vertical) • Weight on bit The modules receive the data and

process and interpret them. The identi-fication module identifies, on the basis of input mud-logging data, the current operation among several possibilities

This article, written by Assistant Tech-nology Editor Karen Bybee, contains highlights of paper OTC 20652, “Field Implementation of a Real Time Drilling Problem Diagnostic for Deep-water Exploratory Wells,” by Roni Gandelman, Alex Waldmann, Andre L. Martins, SPE, Gleber Teixeira, and Atila Aragão, Petrobras, and Mauricio Rezende and Alexandre de Mari, ESSS Scientific Software, originally prepared for the 2010 Offshore Technology Conference, Houston, 3–6 May. The paper has not been peer reviewed.

Copyright 2010 Offshore Technology Conference. Reproduced by permission.

Implementation of a Real-Time Drilling-Problem Diagnostic Program

DRILLING MANAGEMENT

The full-length paper is available for purchase at OnePetro: www.onepetro.org.


such as drilling, circulating, reaming, and tripping in or out. The transient-hydraulics module predicts solids con-centration, equivalent circulating den-sity (ECD), and pump pressure and is composed of two different parts.

The heat-transfer part of the tran-sient-hydraulics module predicts a temperature profile in the annulus and inside the drillstring on the basis of geothermal gradient, flow rate, and drilling-fluid properties. Temperature plays an important role in oil- and water-based-fluid rheology and in oil-based-fluid density. The fluid-rheology variation affects solids-transportation and friction-loss calculations. Thus, the correct prediction of temperature effect on drilling-fluid properties is essential for an accurate prediction of solids concentration, ECD, and pump pressure. After the temperature profile is determined, the module calculates the fluid rheology and density profiles, which will be used in the second part of the hydraulics module.

The solid/liquid-flow module con-tains cuttings-transport transient models that are fed the fluid-rheology and -density profiles (calculated in the temperature module). It receives real-time PWD and mud-logging data dur-ing drilling and on the basis of ROP (solids loading), predicts a solids-con-centration profile (for each timestep). Once a solids-concentration profile is determined, a pressure profile also is determined. For synthetic-based drill-ing fluids, compressibility effects may be important and are addressed in the calculations. In this case, heat-transfer and flow calculations should be itera-tive until convergence is reached.

The torque-and-drag module receives solids-concentration- and bed-height-profile predictions from hydraulics cal-culations, along with other operational parameters such as drillstring rotation, drillstring composition (diameters and weights), and wellbore geometry. Calculations are based on simple mod-els that predict torque and drag.

The surge-and-swab module receives the predicted solids-concentration and bed-height profiles (that directly affect pressure variation resulting from surge-and-swab effects) and drill-string axial velocity during trips. The module contains models to predict how bottomhole pressure increases or decreases when the drillstring is tripped in or out, respectively. If there

is no flow rate and the drillstring has an axial velocity, the model predicts increments and reductions of bottom-hole pressure. If the pumps are on, the flow rate reduces the surge-and-swab effects dramatically, and they are not calculated.

The gel-prediction module predicts gelation. Gelation begins when drill-ing fluid is submitted to static condi-tions and is a fundamental property of drilling fluids because it keeps solids in suspension while the pumps are off. Gelation tendency is higher at low temperatures, typical of deepwa-ter conditions. Once the gelled struc-ture is formed, the energy required to break it will be higher and, conse-quently, a pressure peak is observed. In this way, the gelled fluid induces pressure peaks when the pumps are turned on again after a static period. The gel-prediction module uses some correlations to estimate bottomhole-pressure peaks after static periods on the basis of startup flow rate, static time, and fluids properties.

The geopressure and wellbore-sta-bility module receives geopressure and fracture-collapse data and defines an operational window. This operational window is compared with real bot-tomhole pressure (ECD) to guarantee a safe operation. If ECD is close to (or outside of) the limits of the opera-tional windows, the user is alerted and should adopt some action to avoid operational problems. Geopressure and wellbore-stability data are provid-ed by other specialized services within the company.

The interpretation module also is divided into two parts. The first part accounts for deviations between pre-dicted and measured values, using noise filters and considering instan-taneous or average values whenev-er pertinent. A second part contains interpretation rules based on physi-cal fundamentols, pattern recognition, and artificial-intelligence issues. It receives all the predicted parameters (e.g., ECD, pump pressure, and torque and drag) along with all other real-time parameters and compares the real and predicted data. Different behaviors between predicted and real curves can indicate the occurrence of an unex-pected phenomenon, and the method-ology tries to identify it, warning the operators and suggesting corrective or preventive actions.

An example of unexpected behav-ior is when the real pump pressure and ECD curves show a tendency to increase while predicted pump pres-sure and ECD are constant. There are many possible causes for this behav-ior such as inefficient solids removal, annular obstruction, or drilling-fluid degradation, but each one has its own specific symptoms. For example, if the wellbore walls collapse, besides the increment of pump pressure and ECD, there may be an increment in torque-and-drag values. On the other hand, a gas influx may cause a reduction in ECD and an increment in bottom-hole temperature. The methodology might identify one unique cause among the several possible by analyzing all operational parameters (e.g., torque, drag, and temperature) that may have a different behavior depending on the specific symptom of the occurring phe-nomenon. Sometimes, however, it is not possible to distinguish one unique cause for an abnormal behavior. When that happens, a list of possible causes and, for each one listed, possible pre-ventive and/or corrective action to be taken is presented. The interpretations of the different tendencies of the curves are made by hundreds of rules of inter-pretation implemented in the module.

Problems and events the methodol-ogy is able to identify include the fol-lowing.

• Washouts• Bit-nozzle obstructions• Bit-nozzle failure• Wellbore enlargment and/or col-

lapse• Drillstring balling• Bit balling• Annular obstructions resulting

from wellbore collapse or shale/drilling fluid interaction

• Annular obstructions resulting from deficient solids-removal conditions

• Packoffs• Breathing/ballooning• Pit-volume increments• Circulation losses• Pumps-off data analysis • Deficient solids-removal conditionsAs an illustration, one of the inter-

pretation charts analyzes the possible causes of pump-pressure reduction while drilling. Possible causes are gas influxes, washouts, and bit-jet failures. The use of other variables, such as ECD and flow out, would help to identify the correct cause. JPT

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The likelihood of losses increases as reservoir pressures decline while higher mud weights are needed to prevent col-lapse of overburden shales as targets are pushed farther from the platform. Drilling parameters for the Forties field have become fairly well established after years of experience, yet 65% of the wells drilled between 2002 and 2007 experienced incidents attributed to instability. Through a better under-standing of the field geomechanics and past drilling events, the drilling team has implemented fit-for-purpose drilling procedures that have improved drilling efficiency significantly.

IntroductionDiscovered in 1970, the Forties field has been developed and produced from five platforms in the UK sector of the central North Sea since 1974. There are now more than 300 boreholes in the area. In recent years, the drilling program has pursued infill targets from donor wells sidetracked near the base of the 95/8-in. casing or step-out targets with sidetracks higher up existing wells.

Of the 94 boreholes drilled over a 5-year period (2002–07), 45% were lost because of drilling or comple-tion problems. A bottomhole assembly

(BHA) was lost in 40% of these failures. Even the successful wells encountered various drilling problems, and when this is taken into account, 65% of all the wells drilled during this period experienced some degree of insta-bility. As field production declined, economic viability demanded a step change in performance.

Drilling parameters for the Forties field have become fairly well estab-lished after years of experience. Over the period, mud weights tended to creep up in response to cavings and packoffs and then were lowered when losses became of greater concern. Where these events became more than a minor problem, drilling practices fre-quently were responsible. Fragile zones often are stable if undisturbed, but mechanical or hydraulic disturbance will generate debris, sometimes in con-siderable volumes.

Were the holdups, stuck pipe, pick-offs, and loss incidents in the Forties field caused by hole instability as a result of incorrect mud weights or caused by drilling practices? Is the debris in the borehole fresh cavings or unremoved cuttings? If the cause of these problems can be identified cor-rectly, appropriate drilling and opera-tional contingencies can be defined before hazards are encountered. When hole problems do develop, appropriate remedial actions can be taken on the basis of an understanding of what is occurring downhole. Incorrect diagno-sis can lead to an inappropriate solu-tion, exacerbating the problem and leading to further damage.

MethodUsing a geomechanical model that includes stress state and rock strength computed from offset-well data, a con-tinuous mud-weight window is esti-mated along selected well trajectories

to define mud-weight windows and to identify potentially troublesome zones and drilling problems. Analysis of his-torical drilling events and data provides a set of observations with which to ver-ify the predictions of the geomechani-cal model and distinguish problems caused by incorrect mud weight from those induced by drilling practices.

For a proposed well trajectory, the well plan identifies potential hazards, estimates drilling parameters, and rec-ommends practices to minimize the incidence of wellbore instability, and it supplies contingencies for zones where failure is unavoidable. Drilling param-eters can vary, sometimes dramatically, as well angle and azimuth change. Occasionally, a mud-weight window does not exist and formation failure is unavoidable. This does not indicate automatically that the well is undrill-able, rather that the drilling strategy and practices should be aimed toward managing wellbore instability.

During drilling, surface and downhole measurements should be monitored to detect the onset of wellbore instability and minimize the risk of borehole fail-ure or loss caused by mechanical well-bore instability. Measurement while drilling, logging while drilling, surface mechanics, fluids, and solids (cavings) monitoring all can be used to diagnose the wellbore state and compare it to the well-design prediction. The process provides a record of the wellbore-sta-bility information, which can be used to update the mechanical Earth model for future wells in the field if desired.

Geomechanical AnalysisThe geomechanical review involves a brief assessment of the in-situ-stress setting and mechanical properties of the formations in the overburden and reservoir section. The geomechanical model was generated from well data

This article, written by Assistant Tech-nology Editor Karen Bybee, contains highlights of paper SPE 124666, “Managing Drilling Risk in a Mature North Sea Field,” by Brett McIntyre, SPE, Ted Hibbert, SPE, Donald Keir, and Rachel Dixon, Apache North Sea Ltd., and Tom ORourke, SPE, Farid Mohammed, Adam Donald, Liu Chang, Anzar Syed, and Valerie Biran, SPE, Schlumberger, originally prepared for the 2009 SPE Offshore Europe Oil and Gas Conference and Exhibition, Aberdeen, 8–11 September. The paper has not been peer reviewed.

Managing Drilling Risk in a Mature North Sea Field

DRILLING MANAGEMENT

For a limited time, the full-length paper is available free to SPE members at www.spe.org/jpt.


including logs, cores, leakoff tests, and reservoir-pressure measurements. Rock properties and the in-situ stress state estimated from logs were calibrated to core measurements and validated against drilling experience. Subsequent wellbore-stability analysis defines mud-weight windows and identifies poten-tially troublesome zones and drilling problems along the proposed well path.

Several vintages of previous geome-chanical analysis provided a starting point. Refinements incorporated in the current work address the effects of reser-voir depletion and anisotropy related to the layered nature of some formations.

During the course of the study, slabbed cores from several wells were reviewed. From well to well, the char-acter of the same shale (i.e., Lower Eocene or Sele) changed from homo-geneous to highly layered, to fractured. Fig. 1 illustrates examples of these vari-ations. These “imperfections,” which appear to occur in a nonpredictable manner, weaken the rock fabric and are responsible for many incidents of borehole failure. Such significant varia-tions help to explain why no difficul-ties would be encountered in one well while another well experiences severe instability issues.

Geoscientists observed a correlation between acoustic velocity and borehole deviation within the Sele formation. Subsequent investigation to understand the source of this effect led to the realiza-

tion that this correlation was a result of anisotropy related to the layered nature of the formation. From a geomechanical perspective, this causes the rock strength of the Sele formation to be highly vari-able. New core plus -sonic, and -seismic measurements were used to quantify the effects of anisotropy related to bedding planes and weak shales.

Dynamic elastic moduli calculated from full-waveform sonic data show a separation between horizontal and ver-tical shear stiffness within the Sele, but not in adjacent formations. Calculations using phase-slowness curves would result in a decrease in stiffness and rock strength for relative dips between 40 and 55°. This character agrees well with that of the unconfined-compres-sive-strength measurements from core. The stress/strain data from triaxial tests indicate a large amount of nonlinear elasticity and plasticity.

As pore pressure declines with deple-tion, the horizontal stress decreases in depleting sands and increases in the adjacent shales. This decreases the fracture gradient in the reservoir and increases the mud weight needed to control caprock and reservoir shales, ultimately causing the safe mud-weight window to collapse. The amount of change depends on rock properties, relative thicknesses, and the geologic structure. 3D analysis is required to estimate these stress changes properly in both the sands and adjacent shales.

Given the narrow mud window in Forties wells, it is unlikely that insta-bility and losses can be avoided com-pletely, but the consequences can be managed with careful selection of well trajectories, appropriate drilling prac-tices, and stability monitoring during drilling. Drilling and tripping practices should be designed to minimize dis-turbance to damaged zones.

Drilling EventsA review of wellbore-instability inci-dents observed in offset wells has been used to verify the geomechanical model and establish the most likely cause of the instabilities observed. Establishing the location and timing is critical in determining the root cause of an instability event. Unfortunately, this analysis is not always unam-biguous. Conflicting experiences are common, and reliable data often are sparse.

Of the 94 boreholes drilled over a 5-year period (2002–07), 45% were lost because of drilling or comple-tion problems. These failures could be grouped into four categories of imme-diate operational causes: lost BHA, lost borehole, directional issues, and inability to complete. A BHA was lost in 40% of these failures. Further analy-sis of the immediate operational causes revealed four main root causes: hole cleaning, wellbore instability, mechan-ical issues, and directional issues.

Layered

Competent

FracturedLayered shale interspersed with weak layers—some parts fail,others remain intact

Fig. 1—The nature and fabric of shales vary in a non-predictable manner across the Forties field.

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Assimilating the information from more than 90 boreholes can be a dif-ficult task. When wellbore-stability incidents are displayed in time/depth plots, it becomes evident that most problems in the Forties field ocur not while drilling or making connections but when pulling out of hole. This implies that the mudweights selected for most wells are correct (or nearly so) and that many events have been induced by drilling or hole-clean-ing practices.

Well PlanningThe well plan provides a practical method to apply geomechanical knowl-edge to the drilling process. For a pro-posed trajectory, the well plan identi-fies potential hazards, estimates drilling parameters, and recommends practices to minimize the incidence of wellbore instability, and it supplies contingen-cies for zones where failure is unavoid-able. Correct mud weight is only one element of a drilling plan. Operational procedures also are important.

Formation failures associated with the rock fabric are responsible for many well problems. Incorporating knowl-edge of the rock fabric into the plan ensures that the correct procedures are in place to detect these failures and implement appropriate remedial action to guarantee effective management of any wellbore instability.

In the Forties field, the occurrence of some troublesome geologic features (e.g., anisotropic layered shales) cannot be predicted consistently. In the same fashion, it cannot be predicted if a fault or stringer along a proposed wellpath will prove troublesome. The best that can be done is to highlight the potential hazards, prepare contingencies, and watch for early warning signs of a haz-ard developing.

ConclusionsThe knowledge gained during the course of this project has contributed to reducing Forties field 2007 nonpro-ductive-time costs by more than 60% in 2008. In contrast to earlier years, no BHAs have been lost following imple-mentation of the practices identified.

In the Forties Field, mud-weight selection is a compromise between hole collapse and losses. Capturing and clas-sifying drilling events is a key process in understanding the mechanism and causes of wellbore failures. JPT

Aera Energy ........................................... 33

AGR CannSeal ...................................... 21

American Business Conferences ...... 52, 84

AMETEK Drexelbrook ............................. 51

Aramco Services Co. ........................... 113

BJ Services ............................................. 65

Boots & Coots ........................................ 69

Cudd Energy Services .............................. 2

Darcy Techonologies .............................. 63

Dragon Products, Ltd. ............................ 37

EXPRO ................................................ 53

Fairmount Minerals Santrol ...................... 7

Fekete Associates .......................... Cover 3

FMC Technologies ................................. 57

Frac Tech Services, Ltd. .......................... 67

Friedrich Leutert GmbH & Co. KG ....... 105

General Electric Co. ................................ 9

Halliburton ............................... 11, 17, 25

Halliburton Easywell ............................... 95

Halliburton Sperry Drilling ..................... 47

Hexion ....................................................23

IHS ....................................................... 79

Kelkar and Associates, Inc. .................. 105

Kongsberg Oil & Gas Technologies ....... 27

KUDU Industries .................................... 87

M-I SWACO .......................................... 75

MPGE University of Oklahoma ............ 112

National Oilwell Varco ........................... 77

Packers Plus ........................................... 59

Petroleum Institute, Abu Dhabi ............. 111

Polyguard Products .............................. 105

R&M Energy Systems .............................. 15

Red Spider ............................................. 71

Roper Pump Co. .................................... 19

Roxar Software Solutions ........................ 70

Schlumberger Oilfield Services ..... Cover 2, ....................................... 3, Cover 4

Seawell Americas, Inc. ........................... 13

SPE.org .................................................. 40

SPT Group ................................ 39, 81, 91

TAM International .................................. 55

Tejas Completion Solutions .................... 83

Tendeka ................................................. 29

Tesco Corp. ........................................... 49

Tomax AS .............................................. 41

Weatherford International Ltd. ............ 4, 5

Weatherford Laboratories ...................... 54

Wood Group ESP .................................. 44

ADVERTISERS’ INDEX

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Estimated spending on drilling and completions was more than USD 250 billion in 2008. With rig costs esti-mated to consume 37% (or USD 92.5 billion) of that spending, every effort to reduce drilling time has a direct effect on the bottom line. Estimates of nonproductive time (NPT) ran from 15 to 40%, or USD 14 to 37 billion, depending on well type and operator. The causes were varied and includ-ed technical and nontechnical chal-lenges. Obviously, any effort made to reduce NPT will affect bottom-line spending.

IntroductionThe oil and gas industry spends mil-lions of dollars each year collecting vast amounts of drilling data, yet has not made effective use of these data to improve drilling performance. Drilling analysis is a proven technique for improving the return on invest-ment of drilling operations, but com-prehensive drilling analysis has not been a regular part of well planning and operations.

So why is it that comprehensive drilling analysis is not a consistent part of drilling best practices? In part, perhaps, because of the culture. One author suggested that 95% of drilling activities are operationally focused,

placing emphasis on doing, rather than planning or analyzing. Many people in drilling operations thrive on operating by “gut instincts” and succeeding through heroic efforts. While experience dealing with unex-pected events is crucial for success in an environment where uncertainty exists, surely it would make more sense to be taking pride in telling sto-ries about the well where everything went according to plan. Furthermore, while most companies have health, safety, and environmental policies that are “zero-tolerance,” an accep-tance of waste and inefficiency as being inevitable in drilling operations continues. It is difficult to imagine another industry that would accept 60% waste when it is widely known that something as simple as better planning can improve drilling results.

Two other key obstacles to integrat-ed drilling analysis are the inability to manage the volumes of data that potentially could be used in drilling analysis and the historical limitations of traditional well-planning software. The vision for integrated drilling anal-ysis includes the ability to:

• Visualize and correlate low- and high-density data.

• Allow effective sharing of cross-discipline expertise.

• Provide continuous real-time up-dates.

This integrated approach includes technologies to overcome data-man-agement challenges and well-planning limitations, and to implement multi-disciplinary work flows to help facili-tate planning and analysis across an asset team.

Data ProblemThe first step is defining and scop-ing the drilling project, followed by data selection and quality control.

This data selection and quality con-trol is one of the most difficult stages in drilling analysis. Simply increas-ing the amount of data often means nothing more than adding irrelevant “noise.” Large amounts of data are available—a situation that likely will increase as new technologies, such as wired drillpipe, become adopted more widely. However, determining which data are relevant is not a simple task, which often leads to a trial-and-error approach to data selection.

Building an effective data set from the wide variety of available data sources is both time consuming and frustrating. Data exist in multiple formats and from multiple vendors, such as rig contractors, mud loggers, measurement while drilling (MWD)/logging while drilling (LWD), wire-line, and others. Data quality, par-ticularly with manually reported data, is often an issue. There is a natural tendency to want to avoid report-ing negative news, and values tend to be either a quick glance at a dial or, worse yet, hand-picked to match planned values.

Often data must be retrieved from storage facilities, and may exist only on paper or outdated media, such as 51/4-in. floppy disks, which may be difficult to read using today’s technol-ogy. Daily operations reports, end-of-well reports, and various other vendor reports must be sifted through manu-ally to generate a digest or synopsis. This process can take several weeks or even months and generally is finished when time runs out, rather than when a satisfactory level of knowledge has been achieved.

Limitation of ToolsThe majority of the drilling software tools available focus on planning a single well. Existing tools rely on

This article, written by Assistant Tech-nol ogy Editor Karen Bybee, contains highlights of paper SPE 128722, “Increasing Drilling Efficiencies Through Improved Collaboration and Analysis of Real-Time and Historical Drilling Data,” by Catheryn Staveley, SPE, and Paul Thow, SPE, Schlumberger, originally prepared for the 2010 SPE Intelligent Energy Conference and Exhibition, Utrecht, The Netherlands, 23–25 March. The paper has not been peer reviewed.

Increasing Drilling Efficiencies Through Analysis of Real-Time and Historic Drilling Data

DRILLING MANAGEMENT

For a limited time, the full-length paper is available free to SPE members at www.spe.org/jpt.

JPT • SEPTEMBER 2010 83

import of geological data, often with-out direct liaison with the owners of this information. This means that many decisions are made using out-of-date information or data that are out of context from original analysis. Other petroleum-engineering soft-ware tools, such as production analy-sis and reservoir simulators, typically focus on multiple wells, combining historical and current data, simula-tion, and analysis.

In implementing a drilling-analysis solution, it was determined that one of the challenges was that of effective integration of the various types of drilling data: low-density data, such as daily drilling reports and bottom-hole-assembly (BHA)-run summaries; high-density data, such as real-time drilling data and wireline logs; and information from other disciplines, such as geology and geomechanics.

Drilling-analysis implementations often tend to be focused on just one form of this wide knowledge base, and are not oriented toward automatically maintaining these data through real-time updates. Furthermore, many orga-nizations have not yet adopted technol-ogies with these real-time capabilities.

Overview of an Integrated Approach to Drilling AnalysisSeeking to address what was felt to be a gap in the drilling-analysis process, types of functionality were defined. Some examples include:

• Correlation and calculation of drilling and geomechanical properties such as mechanical specific energy (MSE) and rock strength

• BHA- and bit-performance cor-relation

• Earth-model integration• Histogram drilling parameters,

including distribution curve functions• Ability to record and play back a

set of work-flow steps• Filtering of data by depth and

other log values• Ability to implement additional

displays, calculations, and domain objects

• Real-time integration of dataIn addition, it was determined that

key visual displays needed to include:• Well-section correlation• 3D views• Crossplots• Histograms• Composite plots.

Enabling the results in real time is considered to be highly valuable because it would provide the capabil-ity to develop and monitor key perfor-mance indicators, such as current rate-of-penetration (ROP) performance as a function of ROP distribution. Real-time functionality also would allow optimizing well placement within the reservoir (geosteering), improving the accuracy of the Earth model, and optimizing drilling as it is occurring. Typically, analysis of real-time data takes place using an integrated multi-disciplinary approach, and this led to examination of use of Earth-modeling software to achieve project objectives.

Geoscientists have long used, in modeling reservoirs, many of the techniques that the project sought to apply to drilling analysis. Although these tools lacked specific drilling-domain data, it was possible to incor-porate these data, either through use of open software development plat-forms or by compromising on the way in which the data were incorporated. For example, the project team has been able to extract the daily sum-mary from the drilling report and incorporate it as a series of comments, and they were able to completely integrate drilling events and risks as custom objects. Moreover, by using the same set of tools for multiple disciplines, the team has been able to expand the available knowledge to all disciplines involved in the field-devel-opment process. Additionally, by tak-ing an Earth-model-based approach, the team found that they were able to provide much better predictive capabilities, through the ability of the software to help the team see beyond the bit.

Implementing an Integrated-Drill-ing-Analysis Approach Creating the Knowledge Base. The first step in implementing the drilling-analysis system is to create a drilling knowl-edge base. The drilling knowledge base is used for historical drilling data collected on a rig, such as surface parameter data and MWD/LWD data. Other data, such as outputs from real-time viewing software, wireline logs, bit records, BHAs, drilling risks and events, best practices, lessons learned, and any other information valuable to drillers, are loaded into the drilling knowledge base.


Well Planning. After the drilling knowledge base is populated for the project, it can be displayed with respect to other wells in a field and correlated by time, depth, and for-mation, in both 2D and 3D displays, which is unique from a drilling per-spective. By combining these data as described, detailed offset-well analysis can be performed and used for future well planning. Numerous calculations can be performed such as uncon-fined compressive strength, MSE, and unlimited crossplots, graphs, and charts. ROP estimations can be calcu-lated on the basis of offset wells, and optimal operating parameters, such as bits and BHAs, can be identified and uncertainty can be reduced dramati-cally. New wells can be planned on the basis of data from the closest or most pertinent offset wells. Users can create a stick diagram with all of their vendor programs incorporated, along with casing best practices for particular

formations or hole sizes, and display it next to their best offsets for reference. This can be used as a reference tool for the well being planned.

Real-Time Capabilities. The value of real-time data within the drilling knowledge base is the ability to relate what is being seen in real time with patterns and events from the past. This comparison can help make decisions that could potentially cost or save mil-lions of dollars. Real-time capabilities also can provide a robust collaboration tool where the office and rig simulta-neously view all the past and current drilling data within the context of the Earth model by use of a web-hosted application. Current parameters can be displayed next to offsets along with any other data relevant in a single workspace as a collaboration tool for morning calls or meetings. This is an extremely effective tool because it is updated automatically in real time

and requires minimal manipulation on the part of the drilling engineers, thus making them much more efficient. This process can enhance morning calls to rigs and enable drilling engi-neers to make better decisions for the day’s drilling program.

ConclusionsPilot projects have shown multiple applications where this integrated-drilling-analysis approach facilitated the drilling-optimization workflow and the integration of more information while reducing worker efforts. Worker efforts are reduced by having all the drilling data organized in one location and correlated by well, formation, and depth and in two or three dimensions; by enabling engineers to plan around drilling events by referencing the his-torical data quickly and easily; and by the ability to mitigate risks in real time, enhanced by referencing the drilling knowledge base. JPT

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