bluuebunny/crossref_metadata_2025 huggingface dataset:
Applications of Experimental Design in Reservoir Management of Smart Wells
Authors: Esmaiel T. E. H.
Published: December 2007

Smart well technology (down-hole measurement and control) has progressed significantly over the last few years. Significant research has been done on the application of smart well technology to secondary recovery1,2. Later research has applied experimental design to tertiary recovery including the WAG process3,4. Smart wells and their pro-active application have been shown to provide added value.

This paper aims to determine how the oil price outlook provided by different sources affects the results of the proactive optimization. In a current market of oil price volatility the future outlook of oil prices plays a significant role in the decision making process. Experimental design applications provide screening and response surface designs that facilitate the gradient-based optimization of the WAG process with smart wells in a geologically and economically uncertain environment.

The goal is optimization of the global sweep efficiency under economic constraints through the control of the injection size of each slug, the controlled injection rate of each well, the injection location along the well bore, and the production rates and locations.

The surface response approach allows optimization in an uncertain environment. This smart well approach is compared with conventional wells to determine both the increased value and the reduced uncertainty. This is possible since the surface response models facilitate rapid Monte Carlo simulation.
Novel Ways of Parameterizing the History Matching Problem
Authors: Da Silva F. P. T. , Rodrigues J. R. P. , Paraizo P. L. B. , Romeu R. K. , Peres A. M. M. , Oliveira R. M. , Pinto L. B. , Maschio C.
Published: December 2007

One of the challenges when making a history match study is to find an adequate parameterization for the reservoir model. The main assumptions of the geological characterization should be respect and the influence of parameters on the fluid flow simulation results should be taken into account. On the other hand, the number of parameters should be kept within reasonable bounds in order to make the process viable. In this work, three examples of novel ways to parameterize the history match problem will be shown. Two of them are real field cases and one is a synthetic case based on outcrop data. Common to all examples is the choice of parameters that are related to the geological model building process, such as the variogram in a geostatiscal modeling or correlations between petrophysical properties (permeability x porosity, for instance). In this context, the use of a versatile history matching tool was essential, allowing for a quantitative evaluation for the quality of the match and for managing a larger number of parameters, when comparing to the traditional trial and error procedure. These examples show how the combination of a suitable parameterization with a versatile assisted history matching tool can improve both the quality and the efficiency of the history matching process.
Sand Management of Ultra-High-Rate Gas Wells
Authors: Balgobin C. J.
Published: December 2007

Sand production can pose a significant threat to asset integrity, hydrocarbon control and availability of production. As a result sand management is crucial to protecting commercial interest, safety and the environment. Most of the sand production problems tend to be found in relatively shallow reservoir sands that tend to be unconsolidated. The propensity for sand erosion is exacerbated in ultra high rate gas wells where fluid velocities are typically very high.

The Kapok Field is such an example with reservoirs and fluid velocity that are prone to incipient sand production. Surrounding field history and an appraisal drill stem test (DST) results indicate that sand control will be a major challenge to delivering full well potential thereby maximizing the value of the field reserves. This risk was addressed in all phases of the development from appraisal drilling, to the front-end engineering design and the operation of the field. As a result, the plan of development for the Kapok field ensured that sand production was taken into consideration and therefore measures were put in place to manage sand spanning from well placement in the reservoir and well completion design, topside installation of wear monitors on all chokes, the implementation of two independent types of sand detection systems as redundancy, and managing the field through focused well operating guidelines and adhering to a reservoir surveillance plan.

Kapok Field production is on plateau delivering 1.1 Bcfd of gas and approximately 10,000 barrels of condensate per day that will be exported off the Kapok unmanned satellite platform. Customers requiring this daily volume of gas need the assurance that this gas deliverability is not threatened in any way and gas suppliers need to ensure that this deliverability is not compromised such that both parties maximizes return on their investment in a cost effective manner.
Challenges of the 4D Seismic in the Reservoir Management of Marlim Field
Authors: Ribeiro N. , Steagall D. , Oliveira R. , Formiga L. , Kerber P. , Jaeger M.
Published: December 2007

The seismic 4D (Time-lapse seismic), has been globally used as an effective tool in reservoir management. At Petrobras its use is still incipient. A 4D seismic acquisition is being performed in the Marlim field, Campos Basin, Brazil. The main objective is to identify the fluid flow and the undrained areas in order to optimize the infill drilling wells.

The Marlim giant field is located on the eastern Brazilian coast in water depths varying from 600 to 1100m. The reservoir is characterized by an unconsolidated sandstone turbidite related to the regressive megasequence of the Brazilian eastern continental margin. The average porosity and permeability are 30% and 2000mD, respectively. The production started in 1991 and the water injection in 1994. The production is done through seven platforms.

There are two seismic surveys covering the area. The first one, acquired in 1986, has a poor vertical resolution compared to the second one, registered in 1997. The shooting directions of these two 3D surveys are not the same. For the new survey the parameters was quite the same of the 1997 acquisition.

The studies of technical and economical viability have been showing that it will be a challenge to monitor the front progress of water in the field since the impedance contrast among the remaining oil (19 to 24 degree API) and the water injected is not very high. Another challenge in this acquisition is the overcoming of the amount of production structures, that act as obstacles to the conventional seismic acquisition.

This work presents the feasibility studies for 4D seismic acquisition, the acquisition planning and the expectations of its use in the reservoir management.
Optimization of Drilling Well Stage Using a Pressure Profile 3D Model in Cantarell Field, Gulf of Mexico
Authors: Delgado J. , Sanseviero R. , Zepeda R. , Calderon F. , Lopez A. , Morales J.
Published: December 2007

To execute the drilling well plan in Cantarell field, located in the Gulf of Mexico, Petroleos Mexicanos (PEMEX) is implementing a methodology to get a better control during the drilling stage. This methodology uses the conventional available information and a new pressure profile 3D Model. This model has been generated from available information, such as: logs, geologic/geophysics information, pressure values, and drilling mud weight. The methodology is being implemented and adjusted successfully as follow: construction of new wells by recommending casing setting depth after an abnormal pressure zone, determining an operational window for drilling fluids, identification of transitional pressure zones, analysis of the expected dynamic pressures, and recognition of zones with potential torque and drag problems.
Using Seismic Attributes to Estimate Net Thickness in Pinch–Out Areas – Marlim Deep Water Turbidite Oilfield, Campos Basin
Authors: Oliveira R. M. , da S. Ribeiro N. M. , Johann P. R. S. , Camarao Luciano Formiga , Steagall D. E. , Kerber P. A. , Carvalho M. R. J.
Published: December 2007

The Marlim Field was discovered in 1985, about 100 km off the southeastern Brazilian coast, under water depths between 600 and 1,100 m. It is the largest producing oilfield in Brazil (average 500,000 bdp), containing an original oil-in-place volume of 6.4 billion STB and began to produce in 1991, through a pilot system. The field is exploited through 87 producing wells and 45 injectors connected to 7 production floatation units.

The Marlim reservoir is part of the lowstand systems tract of a third-order sratigraphic sequence, which is associated to an important eustatic, sea level fall of about 25 MMy. The turbidite lobes fill an intra-slope, wide depression developed by down slope gliding of underlying, Aptian evaporites. Reservoir facies comprise amalgamated graded beds of poorly consolidated, unstratified, medium to fine-grained sandstones with very low silt and clay contents. Porosities and permeabilities are relatively homogeneous. The Marlim turbidite system was subdivided into nine production zones, mostly on the basis of stratigraphic discontinuities recognized in well logs and cores.

The eastern margin of the field is fault-bounded with the rest of the field limits defined by sand pinch-out that determines the "zero line" of the reservoir. The pinch-out pattern of the sands depends on a series of geological factors, such as the topography of the substratum, the depositional system characteristics, and the intensity of erosive processes, among others. The way of modelling the pinch-out has an important influence in the oil volume since the pinch-out regions occur in a very extensive area of the Marlim Field. Also it has a significant impact in the success of location, navigation and productivity of horizontal wells positioned in the borders.

Considering that several projects of horizontal wells are expected to be drilled in pinch-out areas, the objective of this paper is to present the correlations between seismic attributes and reservoir properties used to improve the estimate of net thickness in pinch-out areas that are below the limit of seismic resolution.
In-Situ Stress Determination Based Upon Borehole Imaging and Rock-Sample Analyses: A Comparison Among Anelastic Strain Recovery (ASR), Acoustic Velocity, and Acoustic Tomography
Authors: Bloch M. , Freitas S. M. S. , Socorro M. , Soares J. A. , Bacelar C. J. R.
Published: December 2007

The orientation of the horizontal in-situ stresses in an oil well at the Potiguar Basin, Northeast of Brazil, was estimated through three different methods: Anelastic Strain Recovery Test - ASR-3D, wellbore Electrical Micro Imaging - EMI, and acoustic velocities anisotropy - VELAN. A fourth and very promising method for acquiring in-situ stress orientation from rock cores, acoustic tomography, is also presented in this paper. The goal of the work was to compare methods dealing with different sources of data, in order to identify a more reliable, though simple and cheap procedure for inferring the in-situ stress orientation. The three methods had very similar results, finding the maximum horizontal in-situ stress at N42,6E (ASR method); N45E (EMI method); and N42E (VELAN method).
Step Change in Reservoir Simulation Breathes Life Into a Mature Oil Field
Authors: Kromah M. J. , Liou J. , MacDonald D. G.
Published: December 2007

Proposal

The BP Trinidad and Tobago (bpTT) portfolio of assets consists of six producing gas assets, three mature oil fields and several undeveloped gas fields. In addition to significant efforts to meet a growing gas demand for Trinidad and Tobago's LNG and domestic markets, the focus is currently on optimization of oil production. Understanding the uncertainties and optimizing depletion plans is key to successful reservoir management in gas and oil fields.

BpTT uses reservoir simulation to history match and then predict future reservoir performance from highly faulted, stacked sands in Trinidad. Traditionally, a reservoir engineer spends a significant portion of the project time in the construction and history match of the reservoir model to gain confidence for performance prediction. Due to time and resource constraints this generally means that only one model is history-matched. A handful of single parametric uncertainties might be investigated, but decisions are frequently based on the one model thought to be most likely.

BpTT began applying BP's Top-Down Reservoir Modeling (TDRM) philosophy [Williams, et al] in October 2003. TDRM uses a genetic algorithm to assist the engineer in building multiple history matches of the dynamic data based on a user-defined precision, ranges and probability distributions for key input uncertainties. This workflow incorporates a variety of reservoir uncertainties in multiple, probable reservoir models, all of which match the production history within specified precision. Future field and well performance is then optimized by evaluating a range of potential outcomes, rather than by prediction from one single description, as often seen in a traditional manual modeling approach.

This paper relates the successful use of TDRM in bpTT for optimization of infill well locations in a mature oil field. It includes the history match of 30-years of production from 13 wells in the Teak field (Figure 1). The TDRM cycle including history match and prediction was completed in three weeks. The study used multiple scenarios with 16 history-matched models to broaden the scope of analysis of the reservoirs in a time efficient manner.
Assessment of Intermittent Gas Lift Performance Through Simultaneous and Coupled Dynamic Simulation
Authors: Filho C. O. C. , Bordalo S. N.
Published: December 2007

The assessment of Intermittent Gas Lift (IGL) by computer calculations using the mechanistic models found in the literature usually approaches the IGL's operating cycle as a sequence of independent non-interacting stages, occurring back-to-back, without overlapping in time; that approach restricts the system analysis to the limited range of operational conditions when such particular behavior indeed exists. In fact, out of such range, some stages of the IGL cycle may be rather simultaneous than sequential, as previously assumed. This paper presents a new IGL mechanistic model and simulation scheme to consider the possible occurrence of both sequential and simultaneous stages throughout the IGL cycles. The dynamics of the IGL cycles is assessed through a simultaneous and coupled variable set of non-linear algebraic and time-differential equations, interactively defined on the run and solved according to the ongoing stages of the IGL cycle. A case study for a typical IGL well, producing from a low productivity reservoir partially depleted, at different operational conditions, shows how the IGL computer simulator can help the operator to set up the IGL parameters to maximize the well production or its economic gain.
The Study of Plurigaussian Simulation's Lithotype Rule in Reservoir Characterization Process
Authors: Normando M. N. , Remacre A. Z. , Sancevero S. S.
Published: December 2007

This paper proposes to evaluate the reservoir characterization of a mature field using advanced geostatistical techniques. In the reservoir characterization process, the lithologic modeling is an essential stage because it will be work as a framework for petrophysical modeling. The objective of this work is to study the impact of the lithotype rule on the connected facies volume through the plurigaussian algorithm. The interesting advantage for the PGS is the rule function, in this paper we analyze different lithotypes rule and their impact on the volume through the connectivity study using the Hoshen-Kopelman algorithm. As results, it was possible to note that the plurigaussian simulation algorithm presented a good capacity to reproduce the initial reservoir characteristics because it respect the lithofacies proportion, proportion matrix and the lithotype rule and was possible noted too that the lithotype rule present a important constrained to the simulation method. In the continuation of this study we can fill the model with the petrophysical properties and saturation data and observed in fluid flow simulation the impact of the lithologic modeling in reservoir characterization processes.
Utilizing Mini-DST for Formation Evaluation
Authors: Coelho A. C. D. , de Camargo C. , Kato E. T. , Legrand V. M. Q. F.
Published: December 2007

Well tests have been widely used for several decades in the oil industry for evaluation of the well productivity and formation damage, estimation of reservoir characteristics such as initial pressure, fluid type, effective permeability and identification of reservoir barriers or boundaries close to the wellbore. Based on the well test objectives and the regulatory constraints, several techniques may be applied: –a single wireline formation test to obtain a single-point static reservoir pressure, used for determining reservoir pressure gradients;–a wireline formation test to obtain the reservoir pressure and a reservoir fluid sample;–a mini-DST, using a wireline formation tester (WFT) to obtain some reservoir parameters in the near wellbore domain in addition to the fluid sample;–a vertical interference test (VIT) using a wireline formation tester with a vertical observation probe to estimate the near wellbore vertical transmissibility;–a closed chamber test to obtain reservoir parameters around the wellbore region while obtaining fluid samples;–a drill stem test (DST) to obtain average reservoir parameters, well productivity, PVT fluid samples and verify possible barriers and/or heterogeneities in the investigated region;–an interference test to check continuity and estimate average reservoir properties between wells;–an extended well test (EWT) to evaluate the production performance of well/reservoir in addition to other various objectives.

Due to the high costs involved in well test operations, especially in offshore exploration wells, the test type must be carefully chosen and properly designed in order to meet its required objectives at the lowest cost. The mini-DST is one of the cheapest options and may successfully be applied to obtain the reservoir static pressure and collect a reservoir fluid sample. In certain circumstances, the vertical and the horizontal permeabilities may be obtained. The WFT commercial tools may test the reservoir with a shorter investigation than the conventional DST, investigating the reservoir in the order of tens of meters. Regardless of the type of test adopted, all the operations must be conducted in accordance with strict environmental standards.

This work presents the mini-DSTs currently performed at Petrobras, indicating the operational and interpretation difficulties in order to highlight their actual applicability.
A Quantitative and Dynamic Risk Analysis Tool for Offshore Well Construction & Repair
Authors: Miura K. , Morooka C. K. , Mendes J. R. P. , Guilherme I. R.
Published: December 2007

The main concern of activities developed in oil & gas well construction is safety. But safety during the well construction process is not a trivial subject. During the well construction, the process transforms the context itself. Actual risk evaluation approaches focus on operational tasks on existent systems, like production plants, and they are based in static analyses of those. In other words, those approaches don't allow a dynamic analysis that evaluates the risk for each alteration of the context. The present paper presents a new methodology for both dynamic and quantitative risk analysis of well construction process. Moreover, it presents a prototype tool developed to support this methodology. With the use of this tool operational risk levels for each moment during well construction can be obtained, without a great effort of professional planning. By this approach, active barriers for each programmed activity can be quantified, given an initial situation. In this way, the dynamic analysis of amount of safety barriers during the well construction process can be easily obtained.
Beating the Marginal Well Performance in a Mature Field: San Francisco Field in Colombia
Authors: Suárez A. F. , Gaviria W. , Pavas J. , Frorup M.
Published: December 2007

Mature fields represent a special challenge in terms of drilling, because the net present value of the wells compared to the well investment diminishes with the degree of maturity. As the value diminishes, less and less time can be invested in reservoir studies to support field activities.Special workflows are therefore required to allow for a screening of potential infill drilling locations as well as a value assessment.

This paper presents the methodology and processes developed to define the infill drilling locations in the San Francisco field, as well as the execution and the results of the wells drilled, completed, and produced. These processes were developed after an unsuccessful drilling campaign in 2001 to 2002 and have helped arrest the field production decline.

The San Francisco field is an example of a mature field producing under a mature waterflooding project, at water cut greater than 90% owing to the level of depletion, an unfavorable mobility ratio, and high reservoir heterogeneity caused by the estuarine depositional environment.

A multidisciplinary team was set up to end with recommendations to ensure the coherence of the San Francisco Field development plan and to establish the 2003 and 2004 Drilling Campaigns. The workflow to identify drilling opportunities includes an analytical approach and a numerical simulation approach.

The analytical approach consisted of accounting for the well declines and the oil in place by sand and by area. This allowed a definition of reserves block by block and assessment of the possibility of production acceleration through drilling. A significant effort had to be given to the production allocation to support this workflow.

The numerical simulation approach consisted of accounting for the difference between the simulation model and the actual production observations. Being able to account for the difference between model and reality allowed determining how much effort is required to come up with a "reasonable" model, when do we stop to do the history matching, and how to adjust the production forecasts to account for the difference between model and reality.
Slickline With Fiber-Optic Distributed Temperature Monitoring for Water-Injection and Gas Lift Systems Optimization in Mexico
Authors: Brown G. , Carvalho V. , Wray A. , Sanchez A. , Gutierrez G.
Published: December 2007

Sensa tube with fiber optic distributed temperature sensing (DTS) has provided useful real time information for Pemex in various wells through thermal analysis of distributed temperature data. Four case studies are presented in this paper: the first case corresponds to a water injection profile survey at a Northern project. The other cases are related to gas lift optimization in the Northern and Southern Mexican regions.

As a part of the Pemex operated secondary recovery project in a Northern field, Fiber Optic Distributed Temperature Sensing technology has been used to monitor the water injection and warm-back temperature profiles across two perforated and fractured intervals, revealing the preferential flow into a one interval. The DTS thermal analysis provided important information to Pemex, which used the results as a guideline to take corrective action to increase the efficiency of their secondary oil recovery project. Pressure transient data was also collected to aid in the interpretation of the system using memory pressure gauges run on the fiber optic Sensa tube.

The remaining case studies will demonstrate DTS gas lift systems optimization projects. One of these cases shows an example of an efficient gas lift system, meaning no need of post work-over well intervention. The other two case studies reveal issues with the gas lift system design, which compromised the lift efficiency and consequently the well productivity.

Data acquisition using a portable fiber-optic Sensa tube unit has provided important information in a cost effective way. The DTS measurement provides a real-time and continuous temperature profile of the entire well, enabling the operator to monitor simultaneously all the gas lift valves, which is not possible to achieve with the usual time-consuming PLT surveys. Ultimately, the DTS monitoring has proven to be an efficient and reliable tool, saving the operator well intervention time and allowing immediate rectification of the issues observed.
Successful Application of Foamed Viscoelastic Surfactant-Based Acid
Authors: Mohammed S. K. , Nasr-El-Din H. A. , Erbil M. M.
Published: December 2007

A vertical well in a carbonate reservoir was damaged due to invasion of large volumes of water from an upper formation. Diagnostic work (temperature survey and chemical analysis of bailer samples) confirmed the communication between the upper formation and the reservoir. Obviously, invasion of large volumes of water can damage the well due to water blockage and the formation of viscous emulsions inside the formation. As a result of water invasion, the well ceased to flow. A workover was conducted on this well to eliminate the downhole communication, but still the well did not flow. Therefore, there was a need for an acid treatment to remove the damage and restore well productivity

The well was perforated after the workover in 112 ft perforated intervals. In addition, the carbonate reservoir is heterogeneous with several high permeability zones. For these reasons, acid placement and diversion were important. A viscoelastic-based acid system was selected to combine diversion and dissolving capabilities in one system. Moreover, the viscoelastic-based acid was foamed to enhance diversion and improve lifting of the spent acid following the treatment. Mutual solvent was added to the pre and post flushes to break the gel formed by the viscoelastic surfactant and help in removing the water blockage.

The treatment was applied using coiled tubing for better diversion in the wellbore. The treatment was very successful and resulted in major increases in oil production (more than 6,000 bbl/day). The well is still flowing at high rates nine months after the treatment. No significant change in water-cut was noted after the treatment.

This paper describes problem identification, fluid selection, and diversion. It will also discuss the first field application of foamed viscoelastic based-acid system.
VASPS Prototype in Marimba Field – Workover and Re-Start
Authors: Peixoto G. A. , Ribeiro G. A. S. , Barros P. R. A. , Meira M. A. , Barbosa T. M.
Published: December 2007

The Vertical Annular Separation and Pumping System (VASPS) represents an innovative concept for subsea two-phase (oil/gas) separation and pumping.A prototype of VASPS was installed inside a dummy well in 2001 at the Marimbá field, located in Campos Basin, Brazil.

The purpose of this paper is to present the second operational phase of this prototype, after a successful rig intervention to change a damaged Electrical Submersible Pump (ESP). This work also presents the improvements implemented in the control and supervision software of the system, designed to increase its reliability, and the overall results obtained after the second start-up.
Application of Intelligent Well Management System to Optimize Field Performance in Golfo San Jorge Basin — Argentina
Authors: Moyano H. , Fiore R. D. , Mazzola R. , Ponce C. , Ferrigno E.
Published: December 2007

This work is based on the experience obtained through the implementation of a well automation system at the Cerro Dragón Contract Area. The key operating device of the Intelligent Well Management System (IWMS) is the Intelligent Well Controller (IWC), which is an electronic device, with a new technology to obtain control of the well based on surface and downhole dynamometric registers, the result of associated parameters and calculations, and the behavior of the electric motor.

The purpose of this paper is to share our experience on the IWMS implementation and its contribution to: reduce the frequency of well interventions, accelerate the detection of well failures and decrease associated Downtime (DT), a quicker response detection at the waterflood affected wells, faster production optimization with new wells, save on energy demand, redesign the field operators' daily routine, define well selection criteria, and relocate current controllers. Taking advantage of the benefits of IWMS, we feel we are getting closer to excellence in the hydrocarbon producing field operations.
How Does Fluid Flow Affect Performance of CO2 Corrosion Inhibitors?
Authors: Gulbrandsen E. , Granå A. , Nisancioglu K.
Published: December 2007

The performance of three CO2 corrosion inhibitor products was tested in an impinging jet apparatus. The test conditions were 40 °C, 1 bar CO2, pH 5, 3 % NaCl. The O2 concentration was deliberately held within two different ranges: 2-4 ppb, and 10-30 ppb. The jet flow velocity was varied in the range 0.5-20 m/s. The flow velocity did not affect the inhibitor performance with the O2 concentration in the lower range. Flow dependent O2 corrosion was observed in the higher concentration range.
Matrix-Fracture Shape Factors and Multiphase-Flow Properties of Fractured Porous Media
Authors: Rangel-German E. R. , Kovscek A. R.
Published: December 2007

Experiments were performed using different fracture geometries, configurations, apertures, flow rates and two scales: pore- and core-scale. These were combined with analytical calculations and numerical reservoir simulation to examine the pattern, mode and extent of imbibition of water into permeable rock matrices. It is found that relative permeability functions for fractured rocks with impermeable matrices are different from those for fractured porous rocks. The experimental, analytical and numerical results, combined with previous studies, demonstrate that relative permeability functions for fractures not interacting with granular matrices are represented by X-type functions. Relative permeability functions for fractures interacting with porous matrices do not necessary exhibit X-type behavior. The shape of these functions is controlled by the rate of water advance through the fracture, that in turn is controlled by the fracture aperture, the injection flow rate, and the imbibition potential of the rock. As water advance through fractures determines, in part, matrix-fracture transfer, generalized shape factors are presented for both unsteady pressure and imbibition processes.
Analysis of Long-Term Behavior in Tight Gas Reservoirs: Case Histories
Authors: Arévalo-Villagrán J. A. , Jorge A. , Gutiérrez-Acosta T. , Martínez-Romero N.
Published: December 2007

This paper presents a production analysis catalogue to study and interpret the long-term production performance of tight gas reservoirs. The objectives of this paper are: to present physical scenarios that cause long-term linear flow in tight gas reservoirs, to present a catalogue of reliable, straightforward, and stepwise methodologies to analyze production data of tight gas wells in order to estimate reservoirs properties, OGIP, and movable gas reserves, to apply the production data analysis methodologies in actual tight gas wells, and to validate the results using numerical simulation. As a results we found that: 1. long-term flow in tight gas wells may be developed and controlled because the presence of natural fracturing in the reservoirs, 2. actual field data shows long-term transient flows with boundaries for years in a large number of wells that are producing from low permeability gas reservoirs, 3. long-term transient flow and short fracture half-length in various post hydraulic fractured wells suggest the need to develop tight gas field in a tighter spacing between wells, and finally 4. OGIP may be determines accurately without knowledge of porosity, drainage area, and thickness.
CO2 Corrosion Rate Prediction in Vertical Multiphase Flow
Authors: Adsani E. , Shirazi S. A. , Shadley J. R. , Rybicki E. F.
Published: December 2007

The mass transfer coefficient plays an important role in predicting corrosion rates. Using similarities between heat and mass transfer mechanisms, a mechanistic model is proposed to predict heat and mass transfer coefficients for two-phase flow in vertical pipes. The mechanistic model is evaluated by using water-air heat transfer experimental data obtained from the literature. The mechanistic model is also compared with commonly used empirical correlations. In comparison with available heat transfer correlations, the mechanistic model performs very well for vertical annular flow, bubbly flow and slug or intermittent flow that were considered. The mechanistic model is based on physics of two-phase flow and thus is expected to be more general than empirical correlations.
Delivering Environmental Assurance in a Global Organization
Authors: Sealy I. M.
Published: December 2007

Proposal

Providing assurance to both external regulatory or best- practice standards, and to internal company standards presents a special set of challenges when an organization operates across a wide range of countries, business environments, and regulatory regimes. This paper describes a management system that has been developed, and implemented at five hundred sites in one hundred countries, over a one-year period to address this diverse set of assurance challenges.

A review in 2003 of the existing globally implemented environmental management system identified a number of requirements for improvement. These included a more robust system of assessment and assurance of external legal compliance; an improved internal audit and self-assessment process, and a clearer demonstration of alignment of the management system with established external best-practice standards.

Implementation of the new management system, together with a self-assessment and audit toolkit began in early 2004. The system was supported by a set of guideline and template documents that gave field users practical support for local implementation of the system. One of the Guidelines provided detailed instructions for the process of assessment of local regulatory requirements, and for the development of compliance procedures, at a site- or country-specific level in the organization.

An aggressive set of implementation objectives were set for the twelve-month period in which the system was globally implemented. Of the approximately five hundred sites that were required to use the system, 95% were required to conduct a self-assessment, and 60% were required to conduct an independent internal (company) audit by the end of 2004. Progress towards these objectives was measured via the established on-line QHSE database system. With a year's experience of system implementation, a review was conducted at the end of 2004 and was used to develop new objectives, and to identify requirements for further system improvements in 2005.
The Essence of Effective Integrity Management — People, Process and Plant
Authors: Ciaraldi S. W.
Published: December 2007

Effective integrity management (IM) is critical to the control of major accident hazards in oil and gas production operations. To achieve effective IM, it is necessary that an aware workforce deploy quality practices to sound facilities. An easy summary statement, but complex and difficult to achieve in practice. Based on the author's experiences with production operations on five continents, important people, process and plant requirements for acceptable IM are reviewed. Pitfalls encountered are also described, with examples of successful recovery noted.

People requirements start with leadership, accountability and competency, but go beyond to shared vision, passion to achieve and willingness to challenge the status quo when necessary. People are the first priority for IM, as they are often able to overcome shortcomings in process and plant; the reverse is generally not possible.

Hazard awareness, understanding and management is the cornerstone process for effective IM. If dangers are known and widely understood, effective means to mitigate and control can be devised, implemented and tracked. Other important processes include robust management of change (MOC), engineering practices, operating procedures, incident investigation processes, emergency response procedures and performance scorecarding.

IM plant requirements start with inherently safer design, quality procurement, fabrication and commissioning. These progress to practices for sustaining safety critical equipment including inspections, chemical treatments, monitoring and effective repair and maintenance programs. For the latter, testing and assurance around process safety protective systems is especially important. Finally, modifications to facilities to systematically reduce risk should not be forgotten, particularly over the long producing life of some assets. This may involve correcting existing deficiencies or the introduction of new technologies to do things better.
Computer Models Address Drilling Waste Management
Authors: Bloys J. B. , Fleming C. , Ivan C. , Piper W. A.
Published: December 2007

As part of the well planning process, the professional drilling engineer is confronted with the issue of drilling waste management. Frequently, the drilling engineer has little or no experience or training to deal with the variety of issues involved with drilled cuttings and waste drilling fluid disposal. Waste management is also becoming a larger part of total drilling costs and poses definite potential future liabilities to the operating company. One of the ways to fill this need without formal training is to provide the untrained engineer with computer software based on previous experiences. In this manner the untrained engineer can learn on-the-job without costly mistakes due to inexperience.

This objective of this paper is to discuss recently developed computer models that address drilling waste management issues. Some of the models discussed are: ■Solids control efficiency■Waste volume/mass generation■Pit sizing for onshore waste collection■Box needs for waste transportation■Technical feasibility of offshore disposal options■Liability associated with disposal options■Cost of offshore disposal options■Treatment requirements for disposal or re-use options■Land requirements for land application of drilled cuttings

While computer modeling is not new, the application of it to drilling waste management is certainly new. For instance, a bonus-malice system is used to evaluate liability and feasibility associated with offshore disposal options. This allows more realistic evaluation of disposal options. A second innovation is in the use of reverse-wave engineering. Applied to drilling waste disposal, the final disposal or re-use option is selected and treatments are suggested that meet the input and disposal criteria.

While the obvious advantage is to provide artificial intelligence to the user, there is another major advantage to software approaches to drilling waste management. The computer-based approach allows multiple, rapid evaluations of complex variables. The relationship between drilling parameters, waste handling, treatment, and disposal options can be better examined.
Leadership and Safe, Productive Culture and Workplace—A Case Study in Improving Safety Through Leadership Development in Drilling and Completions Operations
Authors: Karish J. , Siokos G.
Published: December 2007

Many oil and gas organizations have grappled with the best way to show visible leadership necessary for sustained safety performance.

Over the past 3 years, EDN has worked with a number of Operators and Contractors to develop and implement an HSE Leadership Development Program designed to develop leaders’ skills to integrate safety into their work and build confidence and competence to lead their people in improving safety outcomes. In effect, become visible leaders for safety.

The HSE Leadership Development Program begins by developing a greater understanding of the organization's safety vision and values and then exploring and experiencing leadership, team behaviors and skills necessary to achieve safe work outcomes. It ends with participants developing action plans that are revisited shortly after the Program ends with coaching to extend learning and assist in the plan's implementation.

The Program provides feedback for each participant that is prepared as a result of behavioral observations made during the Program by trained observers. The feedback is focused on specific HSE Leadership Competencies, including: ➭An ability to describe the organization's business context and how HSE features in business success.➭An ability to integrate safety systems with all other business systems to ensure their seamless application in the workplace.➭An ability to create a work environment and culture where people freely and willingly participate in planning and implementing plans for improved productive and safe work outcomes.

This paper will expand on the structure of this Program and results achieved thus far.

The paper and presentation will cover the development of the HSE Leadership Development Program since its inception in BP to its various forms in other organizations.
Breaking the Safety Plateau: A Successful Implementation of Behaviour-Based Safety Across a Range of Cultures, Facilities and Functions
Authors: Younes N.
Published: December 2007

BG Group, a leading oil and gas company operating in over 20 countries, enjoyed a long period of consistent safety performance improvement through the development of robust safety management systems and processes and a strong top- down drive from the company's Management team. However, the rate of improvement, as measured by the lost time injury frequency (LTIF), reached a plateau with a risk of deterioration. A step change in HSE management was required to avoid complacency and further improve the safety performance past the identified plateau.

To measure the company's safety performance, a range of proactive and lagging indicators is used. The results from these lagging indicators are aligned with a body of published studies demonstrating that as many as 95% of all workplace incidents are triggered by unsafe behaviours. It is therefore by focusing on safety-critical behaviours, as proactive indicators of performance, that the company management intended to reduce incidents and bring about continuous improvement.

The implementation strategy was developed centrally in consultation with all stakeholders within the business units. Support was then requested from the Corporate HSSE Committee to introduce a Behaviour-Based Safety (BBS) process based on the ABC model (Antecedent, Behaviour, and Consequence). A target was set to start implementation in 10 facilities within the first year.

This target was achieved with behaviour-based safety processes developed for oil and gas exploration, production, transmission or distribution facilities in places as diverse as North Africa,Kazakhstan,India,South America or the North Sea.

This technical presentation describes the process of choosing adequate BBS implementation strategy to ensure management buy-in, workforce ownership and a strong focus from all on delivering continuous improvement.
The 14-Point HSSE Assurance Tool
Authors: Younes N.
Published: December 2007

The 14-Point HSSE Assurance Tool is an innovative, electronic tool developed internally within the BG Group to support the company's drive for continuous HSSE improvement. It: Embeds a risk-based approach to HSSE management through a novel risk screening process;Defines the fit for purpose HSSE management system specific to the lifecycle stage of every Business Unit or project;Provides three meaningful scores of Business Unit HSSE performance consisting of: Management System Gap Analysis (MS Gap Analysis) Score which measures the extent to which the required H SSE management system controls have been created and documented;HSSE Perception Survey Score which measures the workforces' perception (from management through to the shop-floor) of the way HSSE is managed in the company;Behavioural Survey Score which measures the effectiveness of application of the HSSE Management System controls;Provides support and promotes knowledge sharing via an integrated HSSE Toolbox, which gives guidance and good practice for each proposed control;Allows for benchmarking of performance both within and external to BG Group;Is designed for use by non-HSSE professionals.

The name of the tool is derived from the 14 elements of the HSSE management system illustrated in Figure 1.
Pore-Scale Modeling of Three-Phase WAG Injection: Prediction of Relative Permeabilities and Trapping for Different Displacement Cycles
Authors: Suicmez V. S. , Piri M. , Blunt M. J.
Published: December 2007

We use a three-dimensional mixed-wet random network model representing Berea sandstone to compute displacement paths and relative permeabilities for water alternating gas (WAG) flooding. First we reproduce cycles of water and gas injection observed in previously published experimental studies. We predict the measured oil, water and gas relative permeabilities accurately. We discuss the hysteresis trends in the water and gas relative permeabilities and compare the behavior of water-wet and oil-wet media. We interpret the results in terms of pore-scale displacements. In water-wet media the water relative permeability is lower in the presence of gas during waterflooding due to an increase in oil/water capillary pressure that causes a decrease in wetting layer conductance. The gas relative permeability is higher for displacement cycles after first gas injection at high gas saturation due to cooperative pore filling, but lower at low saturation due to trapping. In oil-wet media, the water relative permeability remains low until water-filled elements span the system at which point the relative permeability increases rapidly. The gas relative permeability is lower in the presence of water than oil because it is no longer the most non-wetting phase.

We show how to use network modeling to develop a physically-based empirical model for three-phase relative permeability. We demonstrate that the relative permeabilities are approximately independent of saturation path when plotted as a function of flowing saturation. The flowing saturation is the saturation minus the amount that is trapped. The amount of oil and gas that is trapped shows a surprising trend with wettability - weakly water-wet media show more trapping of oil and gas than a water-wet system due to the complex competition of different three-phase displacement processes. Further work is needed to explore the full range of behavior as a function of wettability and displacement path.
Geomechanics Considerations for Through- and Near-Salt Well Design
Authors: Willson S. M. , Fredrich J. T.
Published: December 2007

Over the next decade a significant amount of exploration and new field developments will take place in salt provinces around the world - in the deepwater Gulf of Mexico, and offshore Angola, Brazil, and North and West Africa. Salt formations provide both opportunities and challenges to the design and construction of the often complex wells to be drilled in these locations. An overview of the many geomechanical considerations necessary to ensure successful well construction when drilling in through-, sub- and near-salt environments is presented. The structural styles of deformed sediments adjacent to salt, combined with stress perturbations caused by the presence of salt, are used to assess the risk of encountering zones that might cause wellbore instability or lost-circulation problems. Well design examples are provided that show how near- and through-salt uncertainties may be included within a geomechanical well design for required mud weights while drilling.