bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improving Stochastic Evaluations Using Objective Data Analysis and Expert Interviewing Techniques
Authors: Hawkins J. T. , Coopersmith E. M. , Cunningham P. C. 
Published: December 2007

Abstract
Probabilistic treatment of parameters in economic analysis has become widespread in the petroleum industry. Methods consist of either Monte Carlo simulation or approximations of full stochastic distributions for use with decision tree analysis of varying complexity. Unfortunately, however, although many agree that proper quantification of uncertainties is critical for stochastic evaluation of project economics, post audits indicate the description of key variables to be suboptimal.
Studies across multiple industries confirm that it is more common for actual parameters used in project economics to fall outside of their predicted ranges, than inside. Many suggest this to be due to both motivational and cognitive biases – repeatedly resulting in commonly stated ranges, which are too narrow.
The authors contend that narrow, or sub optimal, variable ranges often result from a lack of use, or misuse, of available data and methodology to counteract inherent bias. In exploration prospect and play valuation, where lack of direct data is an issue, analogous data may be used, but may not be well understood, or well thought through as to how well it represents the prospects and plays the practitioner is attempting to describe. In fact, in the absence of data, many use distributions not commonly found in nature.
Hence, it is the goal of this paper to present a heuristic overview of subsurface parameter distributions for commonly used properties in stochastic economic analysis, and describe an expert interviewing methodology to improve variable descriptions. The authors propose that it is the combination of both relevant objective data and quantification of subjective uncertainty that will improve variable descriptions.
This paper presents the results of a survey of some of the exploration/production areas in North America, along with the distributions encountered and properties of those distributions, from empirical data. Examples are from the Gulf of Mexico (GOM), Permian Basin, and the Western Canadian Sedimentary Basin, with a view to gain insight into the distributions and trends of the properties of key subsurface variables.
In addition, this paper presents the probability method to achieve better descriptions of variables. The authors suggest that although several subjective uncertainty assessment methods exist, the probability method is preferred due to its ability to counteract biases. This paper describes the steps of the probability method for range variable assessment, and explains the tools and rationale for each step.
Sums and Products of Distributions: Rules of Thumb and Applications
Authors: Murtha James A. 
Published: December 2007

Abstract
When n probability distributions are added, the Central Limit Theorem provides estimates of the mean and standard deviation of the result. One useful consequence is that the relative uncertainty as measured by the coefficient of variation – the ratio of standard deviation to mean-shrinks by a factor of roughly n. What can be said about the mean and standard deviation of a product of distributions? Both sum and product formulas abound in the oil and gas business. While Monte Carlo simulation generates the appropriate output distribution, some rules of thumb are useful in advance.
Decision-Making Process for a Deepwater Production System Considering Environmental, Technological and Financial Risks
Authors: Castro G. T. , Morooka C. K. , Bordalo S. N. 
Published: December 2007

Abstract
The development of petroleum production systems has become more and more sophisticated due to the complexity of deepwater oilfields, requiring cost effective and environment friendly systems.
Petroleum companies generally employ methods of decision that consider the economic indicators solely, the net present value and the internal rate of return, among others. However, other non-economic aspects must also be analyzed during the evaluation of an E&P enterprise.
The present work presents a model for decision-making that takes into account the main goals of a company, through the use of the theory of utility functions and multiple attributes.
Besides introducing the mathematical theory behind the proposed model, this work illustrates its application via a current example: a deepwater field with a production potential of 100.000 barrels per day, where the facilities alternatives are a Semisubmersible Platform (SS), a Floating Production System and Offloading (FPSO) and a Tension Leg Platform (TLP).
The case study was framed in terms of the technical risks of the project. The selection of the best option considered the financial risk, the environmental risk, the safety risk and the technological risk.
The results suggest that the best alternative is not always the one exhibiting the best economic indicators.
Advanced Openhole Completions Utilizing a Simplified Zone Isolation System
Authors: Coronado Martin P. , Bjørkesett Halvard , Jiral Dennis G. , Førdedal Harald 
Published: December 2007

Abstract
As openhole completions become increasingly more complex, the need to create annular zone isolation within the borehole becomes critical for effective production or injection. Intelligent completions using gravel packs and stand-alone screens across the payzone are becoming a reality, with positive zone isolation a necessity. Historically, creating zone isolation within openhole completions has required a relatively complicated process, utilizing External Casing Packers (ECPs) that must be inflated during the completion installation. As long-term applications require cement inflation to minimize adverse effects on the packer, the installation process is further complicated, especially in highly deviated and horizontal wellbores.
Utilizing the latest packer construction and materials technology, a non-inflatable openhole packer system has been developed which simplifies the installation operation and creates a positive annular seal, even in non-circular wellbores, while reducing overall risk to the operator. Composite material fabrication allows the mechanical packing element of the packer to expand and seal in irregular-shaped holes (washouts), which have proven difficult to effectively seal using conventional technology. The packer has been designed with a hydrostatic pressure driven setting mechanism, allowing one-trip installations utilizing a shifting tool run on the bottom of the inner workstring. Used in conjunction with other emerging technologies, this new zonal isolation system is compatible with horizontal gravel packing operations, allowing the packers to be expanded against the borehole wall after the gravel pack is displaced.
This paper will describe the collaborative effort between a key North Sea operator and major service company in developing a simplified and reliable method to create openhole zone isolation. The packer and system design process will be reviewed along with a discussion of the verification-testing program used to validate the design. A summary of actual field applications employing this new system will also be presented, along with technical and operational comparisons to traditional isolation methods.
Integrating Fracture Mapping Technologies to Optimize Stimulations in the Barnett Shale
Authors: Fisher M. K. , Wright C. A. , Davidson B. M. , Goodwin A. K. , Fielder E. O. , Buckler W. S. , Steinsberger N. P. 
Published: December 2007

Abstract
A large hydraulic fracture diagnostic project was undertaken in the summer of 2001, which integrated fracture diagnostic technologies including tiltmeter (surface and downhole) and microseismic mapping. The extensive data gathered resulted in a much clearer understanding of the highly complex fracture behavior in the Barnett Shale of North Texas. The detailed fracture mapping results allowed construction of a calibrated 3-D fracture simulator that better reflects the observed mechanics of fracturing in this fractured-shale reservoir. More than just simple calibration was required. Indeed, a whole new understanding of fracture growth was developed.
The Barnett Shale has seen a rebirth of drilling and refracturing activity in recent years due to the success of waterfrac or "light sand" fracturing treatments. This extremely low permeability reservoir benefits from fracture treatments that establish long and wide fracture fairways, which result in connecting very large surface areas of the formation with an extremely complex fracture network.
Understanding the created fracture geometry is key to the effectiveness of any stimulation program or infill-drilling program, particularly in this area with its non-classical fracture networks. Integrated fracture diagnostics have led to the identification of new fracturing techniques as well as additional refrac and infill drilling candidates. A new method for evaluating large microseismic data sets was developed. Combining the microseismic analysis with surface and downhole tilt fracture mapping allowed characterization of the created fracture networks. Correlations between production response and various fracture parameters will be presented along with a discussion of methods for calibrating a fracture model to the observed fracture behavior.
Running Two BHP Gauges to Determine Fracture Growth and Entry Pressure: A Case Study in Canada
Authors: Rueda J. I. , Gu H. , Vandenborn C. , Thompson D. 
Published: December 2007

Abstract
Hydraulic fractures are sometimes designed to start in an upper pay zone and grow into a lower pay zone(s) to avoid generation of multiple fractures during the treatment or to prevent sand production. For such treatments, there is no published methodology to confirm if the fracture actually grows into the lower pay zones. Another issue that engineers must address is that the measured pressure in the wellbore always includes the entry pressure (perforation, microannulus and/or tortuosity), complicating pressure interpretation and making fracture diagnosis difficult.
This paper discusses how running two non-communicating bottomhole pressure (BHP) gauges for a fracture treatment gives reliable and useful information about height growth, and entry pressure. Moreover, the proposed configuration of BHP gauges gives a continuous, direct fracture pressure measurement without being affected by any entry pressure; i.e., the pressure immediately inside the fracture is measured. We will present a field case where such a configuration was used to confirm that the fracture originated in the upper pay zone and grew through a 7-ft thick shale to connect a lower pay zone. Two gauges were run as follows: one memory gauge below a bridge plug to monitor the lower perforated pay zone, and one surface readout gauge (real time) within the frac string to monitor the bottomhole pressure of the upper perforated zone being treated. For this case we confirmed that the fracture did indeed grow into the lower pay zone during both the minifrac and the main treatment. We were also able to measure exactly how much entry pressure was present during both the minifrac and the main treatment. In addition, conflicting pressure behaviors from the two gauges were observed during a sequence of injections and shut-ins and are explained later in the paper. The explanation leads to the conclusion that a conventional BHP measurement may yield pressure behavior that is misleading for pressure diagnostics.
Towards Zero Fluid Loss Oil Based Muds
Authors: Aston M. , Mihalik P. , Tunbridge J. , Clarke S. 
Published: December 2007

AbstractFluid loss control is an important property of drilling muds which impacts the drilling operation in a number of ways including the prevention of differential sticking and formation damage avoidance. This study reviews the mechanisms of fluid loss control in oil muds. The main focus is an experimental study which probes the function of common additives such as barite and clays, dispersed liquid (the emulsion phase), and materials such as asphalts, gilsonites and polymers. HTHP fluid loss measurements and diagnostic techniques such as particle size measurement, SEM, and neutron scattering were performed to elucidate the mechanisms.It is shown that there are three critical mud components required to achieve extremely low fluid loss: fine clay, the emulsion droplets, and partially-soluble additives such as gilsonites or certain polymers. By optimising the mix, HTHP fluid loss values as low as 0.1ml/30 min at 120°C have been achieved. The gilsonites, asphalts and polymers do not necessarily function as deformable particles in oil muds - they partially dissolve and appear to act at the nanometre scale. Filter cake permeabilities are shown to be similar to that of a shale, hence the problem of obtaining zero fluid loss reduces to that of preventing fluid flow through shales but without the benefit of capillary pressure effects.
Application of Injection Tests for Reservoir Appraisals: A Conceptual Study
Authors: Gan Ronald Gunawan , Yeh Nai-Shyong , Bennett Curtis O. 
Published: December 2007

Abstract
This paper presents a conceptual study to evaluate the effectiveness of injection tests for the collection of dynamic reservoir data during project appraisals. A 2-D xy numerical model was built using representative field data to simulate the process and pressure response during injection and falloff tests for various boundary conditions. Various injection cases were studied: water injection into oil and gas condensate reservoirs, nitrogen injection into oil reservoirs, and nitrogen injection into dry gas, lean retrograde gas condensate, and heavy retrograde gas condensate reservoirs. For the case of nitrogen injection, we used a compositional option to model the phase interactions during the tests. Simulated pressure responses were analyzed using single-phase analytical solutions provided by a commercial well testing software package.
We found that a composite reservoir model provided by well testing software package can be used to analyze the injection and falloff tests data. Permeability and distance to the boundary can be estimated for most of mobility ratios. Permeability found during the injection test is the effective permeability to the injected fluid. For the falloff test, it is possible to obtain the effective permeability of reservoir fluid. Type of boundaries can be detected and the distance from the well to the boundaries can be estimated by using effective system compressibility. The ability of boundary detection and mobility calculations are heavily dependent upon the optimal injected volume, and therefore, rely on proper well test design. For test design, the optimum injection volume is very important since it affects the time required to have radial flow in the uninvaded zone (‘reservoir zone’) which is necessary for the interpretation of reservoir boundary. Mobility ratio affects the length of transition zone and also the interpretation of reservoir boundary. Therefore, test design using a reservoir simulator is critical for determining the injection volume and the phase interactions if any, and understanding the pressure response. In addition to the above results, we utilize the material balance approach to calculate the compartment volume thus enhance the interpretation of injection and falloff tests.
The results of this study provide a new and comprehensive overview of the practical application of the injection and falloff tests for the collection of dynamic reservoir data during project appraisal–with zero flaring.
The Health, Safety, and Environmental Benefits of Real-Time Operations
Authors: Knode Tom , Disatell Joel 
Published: December 2007

AbstractTraditionally, well-construction projects have required ongoing wellsite involvement of various personnel such as individuals representing the operator, contractor, and third party. The movement of people represents exposure to risk related to both travel and onsite operations. Conventional risk-mitigation methods currently include journey management, hazard analysis, and various other administrative controls.With the advent of real-time operations, a new opportunity to help reduce these risks has been introduced. Individuals who, in the past, were required to be on site can now access critical information, provide technical support, make decisions, and implement corrective actions while removed from the location. This improves manpower utilization and reduces cycle time, which can result in decreased exposure to all project personnel.Real-time operations enable all parties to gather and analyze data and take immediate corrective action without being onsite, significantly reducing the risk factors associated with a well-construction project.
Impact of Drilling Activities: Seabed Recolonization. A French experiment.
Authors: Blanchet D. , Camps R. , Dalmazzone C. , Dutrieux E. , Durrieu J. , His E. , Le Minter P. , Senia J. , Galgani F. 
Published: December 2007

Abstract
Due to large constraints on environmental regulations, discharge of drilled cuttings at sea has to be controlled. It is thus necessary to have basic information to contribute to the selection of drilling fluids respectful of the environment. The present study was intended to appreciate under real conditions the impact of cuttings, the capacity of regeneration of the ecosystem and the processes of recolonization. In a first phase, standardized (OSPAR) and experimental toxicity tests, aerobic and anaerobic degradation measurements and lixiviation tests were performed on various types of muds and cuttings (containing diesel oil, two different paraffinic cuts, and glycol). The results of the study demonstrated that:
OSPAR tests show a low toxicity of cuttings. Those containing diesel oil are more toxic The experimental toxicity test using mollusc's larvae is very sensitive The presence of a toxic fraction other than the hydrocarbons in muds has been demonstrated, in particular in muds containing diesel oil The decomposition of hydrocarbons in aerobic conditions is fast (40 days approximately) and slower on the cuttings because of accessibility to hydrocarbons There is no anaerobic degradation after two months on basic oils (diesel oil and paraffinic base oil).
In a second phase, the most suitable measurements were taken within the framework of an in situ experiment at a discharge site in Congo (Africa). Together with this experiment, a complete analysis of benthos was performed after 8 years of deposits. The preliminary results demonstrated:
The zone of extension of the toxicity and the modifications of the benthos is less than a few hundred meters around the discharge site Original fauna is replaced by a more specific fauna
In the more general context of the environmental constraints in the oil industry, our work demonstrated the containment of the impacted zones, the absence of significant risks of modification of the adjacent ecosystems and the possible application to other discharge sites.
The Design, Response, and Field Test Results of a New Slim Hole LWD Multiple Frequency Resistivity Propagation Tool
Authors: Mack S. G. , Wisler M. , Wu J. Q. 
Published: December 2007

Abstract
A new slim hole LWD propagation resistivity tool has been developed that exceeds current commercial specifications for pressure, measurement accuracy, and depth of investigation. The MFR* (Multi-Frequency Resistivity Tool) is designed to operate in borehole pressures of up to 30,000 psi and flow rates of 400 gpm without sustaining damage to the tool or electronics. The MFR operates at both 2 MHz and 400 kHz at antenna-receiver spacings of 20, 30, and 46 inches. All antenna arrays are fully compensated and integrated into the drill collar1 to increase reliability and simplify maintenance. Digital Signal Processors (DSP's) are used to measure phase and attenuation at each transmitter-receiver pair, resulting in 48 absolute measurements. These 48 measurements are combined to produce 12 fully compensated resistivity measurements at unique radial distances from the borehole. The fully compensated antenna design and DSP electronics result in both phase and attenuation accuracy specifications of +/−.25 mmhos and +/−.5 mmhos respectively. The 400 kHz attenuation measurement made at the 46 inch antenna-receiver spacing has a diameter of investigation (DOI) of 197 inches at 20 ohm-m, which is deeper than what is currently available in the industry today. Making resistivity measurements accurately, deeper, and at varying radial distances from the borehole enhance existing applications such as geosteering and inversion modeling.
Field test results acquired while drilling show the response characteristics of the tool in a horizontal well drilled with salt mud and a vertical well drilled with oil based mud (OBM).
Application Of Study Of Bit Selection, Bit Weight And Rotary Speed Practices In Offshore Dubai Drilling Operations
Authors: Myers G.M. , Nordquist E.A. 
Published: December 2007

Abstract
Data on all offshore wells drilled by Dubai Petroleum Company were analyzed for comparison of the Petroleum Company were analyzed for comparison of the effectiveness of different bit types, weights on the bit, and rotary speeds in penetration of the various formations and depth intervals common to this Middle East area. This program was initiated in an attempt to improve penetration rates and reduce per well drilling times. Based on this study, an optimum bit selection, bit weight and rotary speed program was incorporated into drilling plans for subsequent wells drilled in the area. Initiation of this program resulted in a significant improvement in penetration rates, in spite of the fact that some adverse conditions existed, such as formations which have been pressure depleted by production, and drilling pressure depleted by production, and drilling angle holes.

Introduction
An in-depth study of readily available drilling records was used by Dubai Petroleum Company engineers to improve all facets of development drilling. The areas of drilling technology that were critically examined were:–Bit Selection–Mud Practices–Completion Techniques–Bit Energy Levels–Cementing Practices–Directional Techniques
While each of these studies contributed to the improvement of drilling efficiency, this paper will concern itself with the bit selection and bit energy studies. This restriction was made for the following reasons:–Application of the findings of the bit selection and energy studies had the most dramatic effect on efficiency.–Effects of mud properties on drilling efficiency are too subjective to have universal application.–Directional techniques must be studied on afield by field basis. These findings are valid only for the DPC area of operation.–Completion practices are so varied that the present time and motion studies apply only to the DPC situation.
The findings of this study effort were successfully applied in the field. The bit selection energy study was mainly responsible for cutting average drilling time below 20" casing from 26.85 to 21.26 days per well. Application of the entire study reduced overall average drilling and completion time from 54.9 to 46.9 days per well. Average total cost per foot was cut by 5.6% despite a 11.5% increase in per foot was cut by 5.6% despite a 11.5% increase in daily costs and a slightly increased average well depth.
Methods used in the bit selection - energy studies will be detailed at some length. This is not done to advocate that the method used by DPC is the only or even the best one, but rather to show at least one means to attack the problem. Results are shown for the same reason, to demonstrate one way to display the effects of bit selection and bit energy on drilling efficiency.