bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deep Offshore Fluid Evaluation/Connectivity Study
Authors: Levaché Denis , Montel François , Walgenwitz Fréderic 
Published: December 2007

Abstract
In the case of deep offshore reservoirs the connectivity between the different parts of the reservoir appears to be a crucial problem to assess the reserve for each well and therefore for the development scheme.
A decisive input to this connectivity problem could be brought by a multidisciplinary approach between three different skills: ✓Organic geochemistry✓Water geochemistry✓PVT and thermodynamics
This presentation shows how these different skills were integrated in the case of a deep offshore field to give an overall picture of the fluid distribution and of the connectivity between the different parts of the reservoir encountered by the discovery and appraisal wells.
The field is divided into two turbiditic systems of Oligocene and Miocene stratigraphic age. The Miocene system is not significant in this field but the fluid properties in this reservoir give important information on the migration and oil alteration process. The Oligocene reservoir is divided into three turbidite channels and six sheets or levees.
The fluid distribution in the reservoir is modelled by different mechanisms. Each mechanism could be characterised from specific data using advanced data interpretation techniques.
Detailed reservoir fluid compositions, gas logging, gas isotopic measurements and residual salts analyses performed on cores samples are some of the key data used in this study.
The intrinsic limitations of the different techniques are stressed and the meaning of the observed gradients and breaks are discussed.
Two main mechanisms are responsible for the composition gradients in the fluid system: gas flux through the entire fluid system and biodegradation.
The channels, levees and sheets are laterally connected, but not vertically in the wells.
Thermodynamic modelling of the dynamic process leading to the actual reservoir fluid distribution is presented and the consequences on fluid properties profile are derived. Through this example, this paper provides the methodology to deal with dynamic reservoir fluid systems and gives to petroleum engineers the way to avoid many traps during the evaluation procedure.
The main contribution is the integration of several data interpretation skills to reach one of the most difficult objectives of formation evaluation: the connectivity level of the different compartments of a reservoir.
Nonlinear Regression Analysis of Well-Test Pressure Data with Uncertain Variance
Authors: Onur Mustafa , Kuchuk Fikri J. 
Published: December 2007

Abstract
The main objective of this study is to explore the use of parameter estimation techniques that handle cases where error variances (weights) in observed well-test data are uncertain. There are two main sources of uncertainty: 1) The gauge resolution and 2) measurement environment. Many gauges are used in well testing are not well characterized in terms of accuracy and resolution. The measurement environment in the wellbore is very noisy because of high frequency events in the wellbore (any producing interval), eg phase segregation. Because of these uncertainties, in this study, we investigated the use of parameter estimation methods based on the maximum likelihood and presented a new efficient method based on this method. The maximum likelihood method enables one to estimate error variances in pressure data along with the unklnown formation parameters. It is shown that the new method is efficient and powerful in estimating formation parameters from well-test data with uncertain variance. A simulated interval test from the multiprobe wireline formation tester in a single layer system as well as a field interval test in a three layer cross-flow system are used to demonstrate the applicability of the proposed methods.
Advanced Sand Control Completion With Permanent Monitoring
Authors: McKay G. , Bixenman P. W. , Watson G. 
Published: December 2007

AbstractPermanent downhole monitoring can provide valuable information for production decisions without the need to perform an intervention to gather data. This type of technology has been excluded from sand control completions because of the complexity of placing measuring devices in the production interval.This paper describes the completion design of an openhole, horizontal, gravel-packed completion with permanent monitoring equipment in the production interval. As is typical for gravel-packed wells, the completion is run in two trips: the sandface completion is run in the first trip, and the upper completion is run in the second trip. The sandface completion includes two hydraulic lines in a U-tube configuration with a hydraulic wet connector at the top of the completion string. The completion is gravel packed using an alternate path technology that decreases the risk of a failed gravel pack placement due to hole collapse or losses. It also allows placement at lower flow rates, thus reducing the risk of damaging the hydraulic control lines. The upper completion is run and stabbed into the hydraulic wet connect. The hydraulic lines provide a continuous, environmentally protected conduit for the fiber-optic line. Once the upper completion is run and the wet connect is tested, the hydraulic lines are flushed and the fiber-optic (distributed temperature sensor) is installed.
Trends in the Effectiveness of Petroleum Exploration and Development Drilling in the U.S. Gulf of Mexico OCS Region, 1977–1998
Authors: Iledare Omowumi O. 
Published: December 2007

Abstract
As the large and easy-to-find petroleum reservoirs are discovered, petroleum discovery rates are expected to decline over time. Consequently the unit cost of reserves additions will tend to increase because of resource depletion effects. However, the more recent declining trend in finding costs of petroleum reserves and recent sharp increase in finding rates in the U.S. Gulf of Mexico Outer Continental Shelf (OCS) have provoked debates on the role of technical progress on the OCS as an emerging offshore oil producing frontier. This paper reviews trends in the effectiveness of exploration and development drilling in the Gulf OCS region. An analytical model of exploration and development drilling effectiveness is developed, estimated, and applied. The empirical results suggest strong statistical evidence of overall diminishing returns on exploration and development drilling on the OCS. The results also show that the positive impact of technical progress and economic incentives is significantly mitigating the depletion effects on the finding rates and the finding costs of petroleum reserves during our sample period. These results are, however, conjectural.
Produced Water Treatment and Hydrocarbon Removal with Organoclay
Authors: Doyle D. H. , Brown A. B. 
Published: December 2007

Abstract
We present a new technology for removing free and dissolved hydrocarbons from oilfield produced water. Organoclay completely removes free hydrocarbons from wastewaters and also removes dissolved hydrocarbons including benzene, toluene, ethylbenzene, and xylene (BTEX). When used in conjunction with a polishing stage of granular activated carbon, organoclay removes free and dissolved hydrocarbons to levels well below current water quality standards.
Organoclay is produced by combining sodium montmorillonite clay with a cationic quaternary amine salt, which replaces adsorbed sodium by ion exchange. Resulting clay surfaces become organophilic.
Hydrocarbons are removed from water by adsorption. The quaternary amines create organic "pillars" between the clay platelets that increase the interlamellar distance and facilitate the formation of a hydrocarbon partition.
A Novel Approach to Resources and Reserves Determination
Authors: Zolotukhin A. B. 
Published: December 2007

Abstract
Oil and gas reservoirs represent a classic example of systems which description is associated with uncertainty.
Quality and quantity of data at the exploration stages and early phases of field appraisal and field development planning is not sufficient for an adequate application of complex software programs based on detailed information about the reservoir/fluids properties. Lack of data makes an overall estimation of resources and reserves made by conventional deterministic and/or probabilistic methods more subjective and, therefore, less reliable.
Methods of fuzzy mathematics have shown to be an excellent tool for handling uncertainties in a scattered environment, i.e. in situations when statistics is not available and probabilistic methods can fail. Instead, fuzzy mathematics enables to directly incorporate the input data uncertainty in analysis, to handle uncertainties in a most natural way and, therefore, to reduce the risk of subjective judgement and to avoid biased decisions.
The paper describes a novel approach to resources and reserves determination based on fuzzy systems theory and focuses on several examples of its application. It is shown, in particular, that volumetric evaluation of oil-in-place can be effectively done by using fuzzy numbers and interval calculus resulting in cumulative possibility distribution curve for resources of oil of a single field. In case of evaluating resources of a basin this technique coupled with the fractal analysis of resources results in the cumulative possibility distribution curve for the entire basin and enables to determine unexplored potential of the basin, or yet-to-find resources.
Evaluation of [recoverable] reserves can also be effectively done by methods of fuzzy mathematics. A new technique of reserves determination based on a simple analytical model coupled with fuzzy calculus is discussed in the paper. The model accounts for wells’ interference and allows to optimise the total number of wells to be drilled.
Screen Selection for Sand Control Based on Laboratory Tests
Authors: Gillespie George , Deem Calvin K. , Malbrel Christophe 
Published: December 2007

Abstract
Oil and gas production from unconsolidated/weakly- consolidated sands requires a production screen in the hole to inhibit the movement of formation sand and keep the hole open. For open hole completions where the sand control screen directly retains the formation sand, proper screen selection is necessary to provide optimum life and minimum sand passing. Several screen sizing selection criteria are available in the literature such as Saucier, Coberly, Schwartz and others. However, these rules may not always be applicable, especially when premium screens, with metal meshes are used. These screens may use multi layers of wire mesh and its complex shaped pore opening may result in retention performance quite different from wire wrap screen slots.
Experimental work has been done on a very fine (d50 = 115- 130 μm) uniform (uniformity coefficient = d40/d90= 3) and a non-uniform (uniformity coefficient = ca 7) sands on a series of commercial screens segments. These screens include standard wire wrap and also premium grade screens. The testing consisted of pressure drop measurements and sand retention while the screen is subjected to a fluidized stream of sand. Analysis of the data provides a method of measuring screen performance during and after filter cake bridging/building. Utilizing this data, screen performance, i.e. comparative lifetime and sand passing can be projected based on a maximum a pressure drop across the screen assembly. This analysis method is applicable for any type of screen and formation.
Where possible, the results from the experimental tests are compared to prior literature screen selection methods. Graphs of the normalized data allow for a logical selection of the appropriate screen for a given formation sand.
Technical Contribution: A new procedure for the selection of production screens applicable to any formationA comparison of the new method with prior literature methodsA comparison of performance of wire wrapped screens and premium screens.
Improved Uncertainty Management in Field Development Studies through the Application of the Experimental Design Method to the Multiple Realisations Approach
Authors: van Elk Jan F. , Guerrera Lupo 
Published: December 2007

Abstract
The structured multiple realisation approach is emerging as an important tool for uncertainty estimation and management of hydrocarbon reserves. The approach quantifies the reserves uncertainty, by identification of the key uncertain parameters for the reservoir description and by subsequent modelling of the reservoir response for a manageable number of combinations of values for these parameters. However, when this modelling requires reservoir simulation, the approach may lead to a significant time and manpower commitment.
This paper presents a rational approach for optimising the choice of simulation runs, using the method of experimental design. The methodology is designed to capture reserves uncertainty and to provide insight into its management within the development context, while minimising the reservoir simulation effort.
In this method the reservoir simulator is treated as a black box. The input parameters to the simulation incorporate the key uncertainties, while the output (for example, the reservoir recovery response) is uniquely determined by the input. The output examined can be any parameter of importance to the field development decisions. The design ensures the input parameter set for the series of simulations is constructed so that the maximum information can be obtained from a minimum number of runs. Results for any given output parameter from the different runs are condensed into a response function for that parameter. This function typically can include non-linear responses and interactions between inputs. An uncertainty distribution for the parameter can be immediately derived. The method also allows for successive refinement of the response function, by adding additional simulation runs.
When using this approach for ultimate recovery uncertainty estimation, not only is the reservoir simulation effort for reserves quantification reduced, but an increased understanding of the field response can be gained for robust development decision making.
The paper will present the application of the methodology to the Field Development Study of the Legendre North and Legendre South Fields.
The Multiple Realisation Approach at Woodside

Introduction
The Multiple Realisation Approach has been used at Woodside since its introduction into the NWSV in early 1995. This method aims at:establishing a structured uncertainty estimation and management process, andensuring technical study integrity.
Introduction
The Multiple Realisation Approach has been used at Woodside since its introduction into the NWSV in early 1995. This method aims at:establishing a structured uncertainty estimation and management process, andensuring technical study integrity.
Drilling Wastes Treatment and Management Practices for Reducing Impact on HSE: ENI/Agip Experiences
Authors: Ferrari G. , Cecconi F. , Xiao L. 
Published: December 2007

Abstract
A growing awareness and sensitivity of the environmental pressure on E&P industry activities has changed rapidly in world-wide. One of the major troublesome environment complications is the mud exhaust and cuttings disposal problem.
This paper reveals the recent experiences of our Drilling Unit in approach to fluid wastes treatment and management exercises in drilling operations toward minimum impact on HSE. In particular, some innovative wastes treatment and re-using technology approaches are discussed together with case studies to affect how waste mud and cuttings are handled, treated, disposed, and reused. Apart from waste and cuttings treatment, management and disposal processes the presented paper illustrates also Agip policy, Italy regulatory limits on environment issues.
The described new treatment processes can be carried out at well site for all types of operation fluids. After suitable treatment, the wastes can be turned out as useful materials favoring both in situ and for other producing industries.
Good and properly treatment, management and disposal of drilling cuttings and exhaust mud can make oil & gas well drilling more compatible with natural environmental requirements. The reduction of environmental impact became a benefit due to less volume (40%) of wastes generated, less transport (20-30%) used, less accident risks during the transportation witnessed, and zero or minimum wastes to disposal sites were brought.
From different operation case histories of our unit, water (60%) from dehydration of WBM and oil (10%) recovered after clean up from oily cuttings are re-utilized for mud service company at rig site. The treated solids (cuttings and components of mud) are no longer wastes to be disposed but raw materials for 1) cement producing plants 2) bricks and expanded clay producing plants and 3) for land restoration.
The experiences, obtained by Eni/Agip up to date provided the very encouraging results not only from cost saving point of view but also as a great contribution to improvement of environmental impact of our activities. The great contribution was derived from: reducing operation duration;less volume of wastes production;zero or minimum discharge drilling wastes;wastes materials as raw materials for re-use: treated liquid (water and oil) is reused for mud built up, dilution and rig cleaning; treated solids are reused as useful materials.
Layer Productivity Prediction Based on Wireline Logs and Formation Tester Data
Authors: Liu C. B. , Schwab K. , Lin X. J. , Chun Kuang Li 
Published: December 2007

Abstract
The development of an integrated approach to testing, producing and/or stimulating layered reservoirs for oil companies in China, which significantly reduces total operating costs by streamlining operations, has been successfully implemented.
This method links the data from standard open hole and nuclear magnetic resonance (NMR) logs with wireline formation test data and the data from reservoir and petroleum engineering applications.
The methodology entails the following stages: -Calibration of a NMR derived permeability indicator by means of wireline formation testing and/or core data.-A full petrophysical analysis incorporating all available reservoir properties in order to estimate relative and phase permeabilities.-These results are then combined with: formation pressures and PVT data from wireline sampling or production tests run in neighboring wells (or simply from regional knowledge); and, completion parameters. All are entered into a nodal analysis program to simulate layer performance.
Results are predicated on a range of wellhead/downhole pressures and skin factors and the predicted flow rates and water cuts are displayed.
The paper will discuss the methodology of this approach in detail - it's strengths and its limitations. Case studies comparing prediction and actual test/productions results complete this paper.
Pushing the Envelope – Extending the Limits of Current Drilling Technology
Authors: Kamaruddin Sazli , Md Zin Che’ Lah , Sering Lancelot , Good Alan , Khun Lim Hong 
Published: December 2007

Abstract
The practical application of new technologies, including rotary steerable drilling systems are overcoming previous limitations in directional drilling to make designer, multilateral and extended reach wells easier to drill.
In this paper, the authors will discuss the tremendous value that can be achieved through application of winning technology and teamwork that has been proven as an effective tool in maximizing business opportunity in Asia Pacific.
Multilateral wells offer tremendous advantages including reducing the size of platforms, surface locations, subsea completions and total wells required to fully exploit a hydrocarbon reservoir. However, such complex 3 dimensional well applications can be severely limited by a number of factors including: Prohibitive well costsRig sizing considerationsLess than optimal directional controlTorque and dragUnreliable WOB transfer and poor hole cleaningEnvironmental considerations.
One technology having a significant impact on such designer well applications are rotary closed loop drilling systems. These systems provide enhanced drilling-while-steering efficiency and improved hole quality. It comprises a non-rotating steering unit, a downhole guidance system, formation evaluation (with optional LWD) and downhole pressure monitoring. These tools can automatically guide the bit to a preprogrammed target and two-way surface communication allows rigsite engineers to adjust the well trajectory to meet drilling objectives and redirect the wellpath based on real-time formation logs. This eliminates the "wait and see" aspect of drilling which often results in less than optimal well placement, unnecessarily complicating the forward directional plan for the well or missing the target all together.
In 1998 Petronas Carigali Sdn. Bhd. commenced the Sotong field development in offshore Peninsular Malaysia. The objective was to efficiently drain marginal reserves using multilateral Level 4 technology. The wellpaths are precisely placed in an optimal position using rotary steerable technology in order to ensure maximum production life of well. Modern communications systems has allowed this technology to transfer real-time wellsite data from rigsite to shore. The critical well path decisions can be made in real time by the team in the office and relayed to the wellsite instantaneously and changes can therefore be made immediately.
The Optimum Junction Depth for Multilateral Wells
Authors: Brister Ray , Oberkircher Jim 
Published: December 2007

AbstractPlacement of the multilateral junction is one of the most critical elements in the design of a multilateral well. A misplaced or mal-performing junction can have an adverse effect on an otherwise successful multilateral project. The optimum placement of the junction is a function of reservoir, geological, drilling, and completion criteria. The list may include such criteria as reservoir development strategy, pressures & heterogeneity, geological structure, lithology, wellbore stability, multilateral junction integrity, directional drilling requirements, logging requirements, artificial lift design, and completion type. These combined factors have a direct economic impact on the success and viability of the project.This paper describes a process whereby the proper junction selection criteria can be evaluated in light of pertinent technical and economic criteria and examines lessons learned from case histories with junction problems.
Evaluation of CO2 Injection with Three Hydrocarbon Phases
Authors: Wang Xiaowei , Strycker Arden 
Published: December 2007

Abstract
This paper presents results of a slim tube test and detailed 1D-simulation studies of a hydrocarbon system involving three hydrocarbon phases. The principle objective of this study was to evaluate the effect of CO2 injection with three hydrocarbon phases on oil recovery.
The Schrader Bluff (Alaska) equation-of-state (EOS) predicts that two hydrocarbon liquid phases will be formed at reservoir temperature and pressure during CO2 injection. A slim tube test utilizing a 77.5 mole% CO2-22.5 mole% NGL solvent was performed on a freshly made recombination of separator samples collected from the Schrader Bluff E-20 well. Detailed 1D-simulation studies following the test were conducted using an EOS compositional reservoir simulator developed at the University of Texas (UTCOMP).
Both laboratory test and simulation results showed the formation of a second liquid CO2-rich phase. Using UTCOMP, the conducted laboratory slim tube results were successfully history matched. The simulation runs also showed that lumping the CO2-rich second liquid phase into the gas/oil phase, as done by commercial simulators, resulted in 5% lower oil recovery. Additional studies showed that oil recovery was sensitive to the reservoir temperature and pressure. Four-phase relative permeability values generated by different models also had a significant impact on oil recovery.