bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect Of Hydrate Inhibitors On Oilfield Scale Formation And Inhibition
Authors: Kan Amy T. , Fu Gongmin , Watson Malene A. , Tomson Mason B. 
Published: December 2007

Abstract
The effect of hydrate inhibitors on oilfield scale formation has been studied. A self-consistent activity model is presented to model the effect of methanol on carbonate equilibrium, calcite, barite, gypsum, celestite, and halite solubility in a gas/methanol/water/salt solution. The model uses Pitzer theory to model the effect of salt and Born equation to model the effect of methanol. Excellent agreements between the model prediction versus both experimental and literature results are observed. The model has been incroporated into ScaleSoftPitzer®, a scale prediction software specifically written for the oil and gas industries. From ScaleSoftPitzer® predictions, scaling problems can be worsened with as little as 5% (by volume) of methanol in a typical oil and gas production system. Ethylene glycol has a much lesser impact on oilfield scale formation than methanol. The efficiency of common phosphonate inhibitors in the methanol and ethylene glycol containing brines will also be discussed.
Saturation Modeling in a Multilayered Carbonate Reservoir Using Log-Derived Saturation-Height Function
Authors: Kumar Rajesh , Cherukupalli P. K. , Lohar B. L. , Chandra Dinesh 
Published: December 2007

Abstract
The conventional and widely used way of distributing saturation arrays inreservoir simulation models is through porosity-weighted water saturationvalues. In this way, each grid cell has an assigned porosity and initial watersaturation. The porosity and water saturation are estimated with the help ofwell logs using established procedures. However, for producing reservoirs, logderived saturations may not represent initial saturations due to variousreasons like depletion due to production and effect of water injection etc. Oneof the ways to estimate the initial water saturation is by the use ofrelationship between depth and bulk volume of water (BVW). Such relationship, known as Saturation-Height function is used to estimate saturation values awayfrom the well locations and to calculate the hydrocarbons in placevolumetrically. This approach has been used in a multi layered carbonatereservoir of an Indian offshore field.
Layer-wise saturation height functions are developed by establishingrelationships between height above the free water level and bulk volume ofwater derived from the wells drilled in the initial phase of field development.The scatter in the BVW plot has been reduced by further classifying the datafor different porosity facies. These porosity intervals are treated as rocktypes for that layer. Since each layer has a particular range of porosity, different porosity based rock types are identified. Height above the free waterlevel versus water saturation plots are then generated for different rock typesusing the relationship developed for each geological layer.These equations wereused to assign initial water saturation in the reservoir simulation model.
Estimating Subsidence During Coalbed Methane Production
Authors: Fanchi J. R. 
Published: December 2007

Abstract
The purpose of this paper is to show how to estimate geomechanical parameters and subsidence during coalbed methane production using the petrophysical algorithm in an integrated flow model. The integrated flow model has been extended to model production of gas from coalbeds and estimate associated geomechanical properties. The model is applied to coals with desorption properties associated with Fruitland coal and Pocahontas coal.
Application of Decline Curve Analysis in Gas Reservoirs Using a Newly Developed Fitting Equation
Authors: Zelghi Ferhat , Djebbar Tiab , Mazighi Mohamed 
Published: December 2007

Abstract
Decline curve analysis for a gas field is generally difficult with the conventional type curve matching, especially in the early time period. For this reason a newly developed fitting equation is proposed as an alternative for gas field production data analysis. This equation combines both depletion and transient periods. The equation offers the following advantages: Fitting with the new equation is more precise than the conventional type curve matching to obtain decline constant, D, and decline exponent, β, and matching point.The real production data can be fitted directly by the equation without using smoothing techniques.The radial and pseudo-steady-state regions are determined directly from the fitting.For new-developed reservoirs, production data, which may be insufficient with the conventional type curve matching, can be interpreted with the new fitting equation.
In this paper, a case study is presented to illustrate the application of the new equation for decline curve analysis in a gas reservoir.
Specialized Cement Design and Placement Procedures Prove Successful for Mitigating Casing Vent Flows—Case Histories
Authors: Watson Theresa , Getzlaf Don , Griffith James E. 
Published: December 2007

Abstract
This paper documents recent field cases in which attempts were made to mitigate casing vent flows (CVF's) on producing and abandoned wells by incorporating permeability-blocking gels with specialized cement blends. CVF's are defined in this paper as sustained gas pressure on the annuli of producing and surface casings. The amount of gas flow rate can vary from a few bubbles to cubic meters per day. However, when the annuli are shut-in, the gas pressure can build to a significant amount. The procedures detailed in this paper are the result of lab studies and postjob reviews of failed remedial attempts. Specific attention is given to why squeeze-cementing procedures can fail to provide long-term seals against source-gas production from casing vents. In most cases, rework of the abandonment procedures cost the operators over $200,000 CAD.
The studies showed four possible causes of recurring CVF's: Development of thaumasite in the setting cementLeaking isolation toolsIncomplete long-term seal of source zonesIncorrect source detection or squeeze interval
Cement-source quality and bulk handling methods were also investigated, but showed no evidence of probable cause.
This paper explains the findings from laboratory studies and job reviews that lead to improved procedures. These improved solutions were conducted on 23 wells in the later part of 2001.
Innovative Water Shutoff Solutions Using Coiled Tubing Conveyed Inflatable Devices
Authors: Geddes Martin J. , Mackenzie Gordon R. J. 
Published: December 2007

Abstract
With water production continuing to increase from mature reservoirs and the need to enhance hydrocarbon recovery from these reservoirs economically using existing wellbores, the requirement for innovative thru-tubing zonal isolation solutions has never been greater. Due to the complexity of the completion design and reservoir in mature fields, the benefits of high-expansion plugging devices and coiled tubing conveyance for chemical placement have become increasingly important.
Thru-tubing inflatable technology has, for some time now, been providing high-expansion devices to pass through the existing completion and isolate in the liner or casing below. However, as reservoirs deplete and remedial work such as re-perforation is performed, the conditions in which these tools are required to perform are becoming ever more challenging. This paper will focus on two coiled tubing water shutoff interventions using thru-tubing inflatable technology in conjunction with cement or chemical placement. In these interventions, the wellbore conditions were considered particularly challenging – sub-hydrostatic bottomhole pressure, multiple perforated intervals and an existing zonal isolation device in the form of a straddle. These case histories will be examined in detail, with emphasis on the pre-job planning, equipment selection, operational procedures, lessons learnt and post job results.
An Advanced Environmental Management System for Alaska
Authors: Hermannes K. , Lawrie G. , Sealy I. , Thayer R. 
Published: December 2007

Abstract
Oil and gas development in Alaska takes place in some of the most environmentally sensitive operating areas in the world. Federal, state and local governments regulate oil field activities in Alaska. The planning and development of new projects can require permits from as many as 26 different agencies.
Meeting our company goal of "No harm to the environment" in this highly sensitive area required a unique solution. In response to developments in customer, industry and societal expectations for environmental performance in our industry in Alaska, we developed an advanced Environmental Management System (EMS). This paper describes the process of developing and maintaining that system.
Key features of our EMS development program included: formatting the EMS to have the look and feel of the corporate HSE management system for ease of implementation and user understanding; the use of established corporate HSE tools wherever possible; the use of external auditing for assurance, for system benchmarking and for compliance assurance; the development of tools using external best practices where required.
The EMS has been benchmarked against the International Environment Rating System (IERS), an internationally recognized Standard for environmental management. The EMS achieved a Level 3 rating in 2000, and a Level 6 rating in 2001 by independent verification company, Det Norsk Veritas. Level 4 is considered to be the equivalent of achieving ISO 14001 accreditation.
The EMS has been implemented in six operational groups located at five facilities in Alaska and has had an immediate impact on our environmental performance. A significant reduction in spill rates, improved waste minimization and proactive environmental risk reduction have all been delivered. Established performance indictors, such as spill rate, have shown improvements of over 80% during the first the Quarters of 2001. Furthermore, several new environmental performance indicators have been developed to accompany the EMS.
Proactive Surveillance and Phased Development Yields Promising Results from the Aurora Field 30-Years after Discovery
Authors: Young J. P. , Bakun F. E. , Paskvan F. K. , Westergaard E. H. 
Published: December 2007

Abstract
Although three 1969 exploration wells discovered hydrocarbons in the Aurora structure, development was not possible until a scope change to the V-200 exploration well demonstrated commerciality 30-years later. Commencing in June 2000, an aggressive 6-well horizontal and vertical development/appraisal program yielded over 1.75 million barrels of oil in the first year and provided a better understanding of a reservoir previously thought marginally commercial. Investment in reservoir description and proactive surveillance led to accurate decision-making, and with innovations, yielded significant return from a "marginal" field.
Horizontal and Vertical Permeability Determination in Clean and Shaly Reservoirs Using In-Situ Measurements
Authors: Manseur Saadi , Djebbar Tiab , Berkat Ali , Zhu Tao 
Published: December 2007

Abstract
Measurements of reservoir rock properties are a difficult task. These rock properties usually involve costly coring programs plus extensive laboratory efforts. An alternate method to estimate these rock properties is using well-logging methods, which represent significant technical as well as economic advantage.
The purpose of this study is to enhance reservoir description of clean and shaly formations in both vertical and horizontal directions using well-logging data. A new approch has been developed for estimating the J-function in clean/shaly heterogeneous reservoirs. This newly developed correlation has been applied to field data, resulting in good matching. Based on leverett J-function and the new proposed approach for estimating J-function, a new correlation for estimating absolute permeability in the transitions zones has been developed. An investigation of permeability, porosity, and irreducible water saturation relationships leads to develop other two correlations in terms of cementation exponent, m, and saturation exponent, n, for estimating absolute permeability in the irreducible water saturation zones from well-logging data.
The feasibility of evaluating permeability distribution of a heterogeneous formation utilizing geophysical well logs has also been investigated, Ben kahla field in Algeria has been selected as a study area. A methodology has been introduced for estimating permeability profile using core and geophysical well log data.
Several vertical permeability relationships were obtained as a function of horizontal permeability, hydraulic mean radius, grain size, and the amount and/or type of shale. A procedure for determining vertical permeability from well log data is presented. The field data shows that the permeability correlation for predicting vertical and horizontal permeability can be established for a specific reservoir by using core permeability and well log data.
Designing a New Plan for the Redevelopment of a Mature Oil Field by Using Various Technologies
Authors: Chedid R. , Colmenares F. 
Published: December 2007

Abstract
A mature area located in Western Venezuela is enclosed by three main fields, all of them in advanced state of depletion based on the way they have been exploited up to now since 1930. These heavy oil fields have a crude that ranges from 10-14 °API, a viscosity between 1000 and 25000 cp and cyclic steam is the way of stimulation as an standard process for all the new wells and the workovers. Cyclic Steam is becoming less efficient after three cycles application, the steam to oil ratio (&lt;5), which is too low for these fields. Since before reaching this value it used to be around 30-40 for the first three cycles, which is considered a good value. Considering that the oil in place is more than 20 billions barrel of oil and only 23% has been recovered beside the latest static models show that several of the sand bodies has not been drained out as yet. A different strategy or a new plan for the redevelopment of the area is necessary in such a way that the exploitation of these fields could be extended for twenty or more years. This study shows that with good static and dinamic models a reassessment of the whole area can be done, by ways of dividing into regions the fields and applying different producing technologies, some of these technologies are thermal recovery methods as cyclic steam, steamflood, SAGD, electromagnetism and Combustion. All of this will increase the recovery factor up to 80%. The non drained sand bodies could be stimulated by applying cyclic steam in areas of the field with good thermal communication. These are candidates for steamflood and in the areas with clean sand bodies up to 40 ft. Thick, SAGD can be applied. Finally the very depleted reservoirs with low pressure and clean sands are the best for either dry o wet combustion.
Analytical Study of the Wafer Non-Darcy Flow Experiments
Authors: Li Dacun 
Published: December 2007

AbstractNon-Darcy effect is significant for high velocity gas flow especially when gas approaches the wellbore region. A new semi-theoretical equation was proposed to estimate the non-Darcy coefficient and the equation was verified by comparing differential pressures from simulations with their counterparts from the experiments where nitrogen was injected at various flow rates and in several directions into a wafer-shaped Berea sandstone core sample.In this paper, the geometry of the wafer and flow profiles were simplified and an analytical model was developed to provide a quick method to estimate the directional permeability and non-Darcy coefficient. Data from several directions were processed statistically to find the best correlation for the wafer.The analytical study confirmed that the new semi-theoretical equation was effective to be used to estimate the non-Darcy coefficient. The correlation for the wafer developed from the analytical study was found to lie between the parallel-type model and serial-type model and be closer to the latter one. Combination of correlations from analytical and numerical studies led to a general correlation, which was found to be the best for Berea sandstone samples after performances of the correlations in the literature and from this paper were independently evaluated by using the results of non-Darcy flow experiments in the literature.
Cumulative Rock Strength as a Quantitative Means of Evaluating Drill Bit Selection and Emerging PCD Cutter Technology
Authors: Cordy L. , Rogers D. B. , Karsten D. , Davies R. 
Published: December 2007

Abstract
The use of cumulative rock strength as a means of evaluating Polycrystalline Diamond Compact (PDC) drill bit performance has been successfully applied to the Cooper Basin, Australia by Santos Ltd. This has permitted a more engineered approach to PDC drill bit selection with a measurable improvement in overall performance.
As this field application consists of vertical wells, drilled in close proximity with similar parameters and operating conditions, it is possible to gain a high level of comparative data with quantified variables reduced to bit / cutter type and formation.
By cumulating the compressive strengths drilled above a determined limit, it is possible to compare bit runs and quantifiably evaluate existing and emerging bit /cutter types and thereby engineer future selections.
Field results have shown an average increase of 61% in the &gt;25,000 psi Cumulative Overburden Compressive Strength formations drilled by the first PDC in the study area.
The initial success rate for the first PDC to get through the entire hard Namur/Hutton formations was 1 in 19 (5.3%). Utilization of the Cumulative Formation Compressive Strength (CFCS) methodology for bit selection increased the success rate to 75% for the last 4 full runs in the study, resulting in a reduction in rig time and associated costs.
Consequent Incentivizing of Service Contracts and its Long-Term Impact on Drilling Performance
Authors: Spoerker H. F. , Ringhofer W. 
Published: December 2007

Abstract
OMV has been drilling for oil and gas in a roughly 5000-km2-area northeast of Vienna for more than fifty years. Since 1999, previously applied conventional type service contracts were gradually changed to performance-based incentive type contracts, which increased drilling performance up to 50% over a three-year period. The impact of generating "ownership" within the service company’s and contractor’s staff is reflected by both the increased quality of the wells drilled and the enhanced safety record of the rig(s). The paper describes the incentive scenarios developed for a mature operating are, the pitfalls and obstacles that had to be overcome in implementing new contractual concepts in a traditional operating environment and the increases in operating efficiency gained from the new culture.
Pipe Buckling at Surface In Underbalanced Drilling
Authors: Aasen Jan , Skaugen Erik 
Published: December 2007

Abstract
Underbalanced drilling (UBD) with jointed pipe has become routine in the UK sector of the southern North Sea and operators in the Norwegian sector are now introducing the same concept. Typically, the well is kept live during tripping and a rig-assist snubbing unit is employed to handle the drillpipe while pipe-light. Significant surface compressive loading is exerted on the pipe during the snubbing phase. The focus of this paper is two-fold. First we consider buckling of the drillpipe in the snubbing jack and on the drill floor when a static compressive load is applied. Thereafter, we analyze the behavior of ejected tubulars during well entry and exit under live well conditions.
Buckling Models Revisited
Authors: Aasen Jan A. , Aadnøy Bernt S. 
Published: December 2007

Abstract
The complexity of petroleum wells has increased significantly during the past decade. Both inclination and horizontal departure are greater than before, leading to additional demands on well operations. Buckling of drillpipe and completion string is seen as a critical parameter. In this paper we review available buckling models and show applicable theory for practical well operations.
Mathematical Modeling of Gas Kicks in Deep Water Scenario
Authors: Nunes J. O. L. , Bannwart A. C. , Ribeiro P. R. 
Published: December 2007

Abstract
Well control has always been a very important issue in the oil and gas exploitation business, since it involves money savings, people safety and environment threatening. The advancement of the exploration frontiers from onshore to offshore fields, particularly, deep and ultra-deep waters, has increased even more the relevance of kick control and blowout prevention during drilling operations. Widely used drilling practices have been optimized and re-evaluated, so have new technologies been developed to handle specific issues related to deepwater drilling operations, such as reliable and efficient well control practices. This effort has great importance to some countries like Brazil, which have most part of their oil and gas production (close to 75%) concentrated on offshore wells, about 70% of those reserves are located in deep waters. Regarding such scenario, this article presents a comprehensive and discussed literature review about well control in deep and ultra-deep waters, covering the evolution of the analytical and numerical kick models. A mathematical model has been developed to predict the pressure behavior inside the annulus during a gas-kick circulation out of the well in deep water scenarios. Considerations regarding the effects of wellbore geometry, frictional pressure losses, influx expansion, and two-phase flow models have been implemented in the present model. The analysis of the effect of some important parameters in well control in the surface pressure, such as the pit gain, water depth, mud density and pump flow rate are presented.
Modeling Coupled Fracture-Matrix Fluid Flow in Geomechanically Simulated Fracture Networks
Authors: Philip Zeno G. , Jennings James W. , Olson Jon E. , Holder Jon 
Published: December 2007

Abstract
In conventional reservoir simulations, grid block permeabilities are frequently assigned values larger than those observed in core measurements to obtain reasonable history matches. Even then, accuracy with regard to some aspects of the performance such as water or gas cuts, breakthrough times, and sweep efficiencies may be inadequate. In some cases this could be due to the presence of substantial flow through natural fractures unaccounted for in the simulation. In this paper we present a numerical investigation into the effects of coupled fracture-matrix fluid flow on equivalent permeability.
A fracture-mechanics-based crack growth simulator, rather than a purely stochastic method, was used to generate fracture networks with realistic clustering, spacing and fracture lengths dependent on the Young's modulus, the subcritical crack index, the bed thickness, and tectonic strain. Coupled fracture-matrix fluid flow simulations of the resulting fracture patterns were performed using a finite-difference simulator to obtain equivalent permeabilities that can be used in a coarser scale flow simulation. Fractures were represented in finite-difference simulators both explicitly as grid cells and implicitly using nonneighbor connections between grid cells.
The results indicate that even though fracture permeability is highly sensitive to fracture aperture, the computed equivalent permeabilities are more sensitive to fracture patterns and connectivity. The effects of diagenetic cements completely filling smaller aperture fractures and partially filling larger aperture fractures were also studied.
Wet Gas Metering Using Dissimilar Flow Sensors: Theory and Field Trial Results
Authors: Agar Jo , Farchy David 
Published: December 2007

Abstract
This paper addresses a new approach to wet gas flow measurement. The Wet Gas Meter (WGM) combines dissimilar flow sensors to measure the flow rates of gas and liquid in gas well production. The WGM utilizes a vortex flow meter for volumetric measurement and dual venturis with different throat sizes for liquid/gas determination.