bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modelling of Cold Heavy-Oil Production With Sand For Subsequent Thermal/Solvent Injection Applications
Authors: Rangriz Shokri Alireza , Babadagli Tayfun 
Published: June 2014

Summary
Although proved beneficial and economic for thin reservoirs, the cold heavy-oil production with sand (CHOPS) method has several limitations. The sand produced during CHOPS changes the geomechanical and petrophysical properties continuously and results in open channels in the reservoir known as wormholes. Also, the CHOPS method results in a low oil recovery (8–10% original oil in place). This entails a follow-up enhanced-oil-recovery (EOR) process, which is always an option for further exploitation, referred to as post-CHOPS. Assessment of such a process through numerical simulation, as the most inexpensive yet most powerful tool, necessitates a comprehensive modelling approach to capture its dynamic physical nature. Only through such a realistic model can one obtain reasonably reliable reservoir characteristics after CHOPS that are critically important to assess post-CHOPS applications. To this end, we implemented a fractal pattern of different kinds by use of a diffusion-limited aggregation (DLA) algorithm as wormhole domain with a partial dual-porosity approach and a step-by-step simulation technique, taking advantage of a simple mathematical model to integrate the sand-production data with fractal patterns. The wormhole network is assumed to grow with more sand production, respecting geological conditions and well perforation. Moreover, its effective properties and the contained fluid can be controlled along its length and pattern at different steps. Such an option is of great assistance in the history-matching process. The model was validated successfully with available Alberta field data. As a preliminary step to post-CHOPS, several thermal, solvent, and hybrid combinations of both scenarios were considered. The proposed method for CHOPS modelling is a useful approach to initiate a quick post-CHOPS study in practice if sand production history is provided. One may also take advantage of its compatibility with any black-oil, compositional, or thermal simulators.
Sampling While Drilling: An Emerging Technology
Authors: Villareal Steven , Pop Julian , Bernard François , Baxter Martin , Hakam Ahmad , Firth Andy , Megat Amanda , Fey Scott , Haq Shahid Azizul , Vahi Nitin 
Published: June 2014

Summary
Even though it is the early days of the realization of sampling-while-drilling (SWD) as a service, a picture of what might be achievable in practice is beginning to emerge. Previous SWD experience has demonstrated that the sampling process may be controlled sufficiently well that relatively clean samples may be acquired when sampling aquifers drilled with water-based muds (WBMs), and it has demonstrated that the SWD tool and sensors used are capable of operating effectively while withstanding the drilling process. On the basis of this experience, operational guidelines have been formulated, particularly regarding the most opportune time to sample during the drilling process.
The first part of the paper describes SWD in a high-angle appraisal well drilled to assess the continuity and quality of several target sands and to establish the degree of continuity of these sands with the main field. The well was drilled by use of an oil-based mud (OBM). Samples would be acquired after the well had reached total depth so that the most appropriate sampling points could be identified by means of openhole logs. Multiple water-, oil-, and gas-bearing formations were identified. Sampling duties were split between the SWD tool and a drillpipe-conveyed wireline sampling (WLS) tool in an attempt to rationalize the sampling program of the well. To enable a comparison of the relative performance of the two tools, two oil-sampling stations were chosen where multiple samples would be acquired under similar operating conditions by both tools. In addition, water samples were collected at two stations by the SWD tool and scanning was performed at one (wet) gas station to confirm the formation-fluid type. Laboratory analysis of the oil samples at the common stations showed that the contaminations and fluid properties of the samples acquired by the two sampling tools were very similar.
The second part of this paper describes results obtained in an appraisal well and sidetrack in a different field. Both pilot and sidetrack were high-angle wells drilled by use of OBMs. The purpose of these wells was to identify and evaluate the commercial potential of unproduced hydrocarbon-bearing zones. Both wells were drilled to total depth before conducting sampling operations, and no wireline operations were planned in either well. Five oil samples were acquired in the pilot well in two zones, and four oil samples and two water samples were recovered in the sidetrack.
The results obtained during the SWD operations described suggest that it is possible to consistently acquire quality formation-fluid samples during drilling operations, even under less-than-optimal sampling conditions and strict time-on-station constraints. The quality of the samples recovered is sufficient to perform reliable pressure/volume/temperature (PVT) analyses.
Reservoir Conformance Control in Oilfields Using Silicates: State-of-the-Arts and Perspectives
Authors: Lakatos István , Lakatos-Szabó Julianna 
Published: June 2014

Abstract
The paper is devoted to overview of conformance treatments using silicates. As shown, the history of the silicate conformance control goes back many decades, but its benefits and field potentials were not really appreciated for a long time. Until now, the different silicate-based technologies have been used more than hundreds times in Hungary, Serbia, Norway, USA, Oman and other countries. Injection of silicates aimed at water shutoff and profile correction in producers and injectors, restriction of gas conning in gas-capped oil reservoirs, blocking of vertical CO2 migration in a collapsed well, water shutoff in reservoirs having extremely high permeability and faults and even improving sweep efficiency in CO2 flooding. Results of pilots and routine application were critically analyzed from different points of aspects. Recently, the advanced methods based on simultaneous application of polymers, urea, humates, nanoparticles, etc. recognizing that the pure silicate gels have some disadvantageous properties under reservoir conditions. Combination of silicates with different chemicals improves significantly the stability, flexibility of such inorganic gels and makes it possible to cure great variety of conformance problems in both porous and fractured reservoirs. The field jobs demonstrate ample examples for outstanding and positive statistics and lessons to learn. In addition, the application of those exclusively environmental friendly chemicals may open new vistas in improvement of well performance of both producers and injectors.
Model Studies of Oil Displacement from Thin Sands by Vertical Water Influx from Adjacent Shales
Authors: Bobek J.E. , Bail P.T. 
Published: June 2014

Abstract
In reservoirs containing soft shales interbedded with oil-producing sands, it is possible to have water movement from the shales into the sands during reservoir depletion.
This paper presents the results of scaled flow-model tests performed to investigate the efficiency of oil displacement by this vertical influx of water into oil-producing sands. In these model tests, the effects of rate of influx and rock wettability were considered.
Oil recoveries by shale-water influx and by water flooding were compared after 0.4 hydrocarbon volume of water entered the producing sand. This comparison was made for water-wet and oil-wet systems. In water-wet sand, shale-water influx produces slightly less oil than conventional water flooding; in oil-wet sand, shale-water influx produces about one-half as much oil as conventional water flooding. In another type of comparison, it was found that shale-water influx followed by water flooding recovers less oil than water flooding alone. This is true for both water-wet and oil-wet sands. A comparison of tests run at different rates of shale-water influx shows that oil recovery is insensitive to rate in water-wet sand; in oil-wet sand, oil recovery decreases with decreasing rate of influx.

Introduction
Localized subsidence of the earth's surface has accompanied the depletion of some oil reservoirs, particularly in California, along the Texas Gulf Coast, and in the Bolivar Coastal fields of Venezuela. Subsidence occurs when fluid withdrawals reduce the pressure in the reservoir. The reasons for subsidence accompanying a reduction in reservoir pressure are not known with certainty. However, there is considerable evidence that compaction of soft shale beds adjacent to producing oil sands can be a major cause of this subsidence. When the shales compact, a limited amount of water moves from the shales into the producing sands. A schematic illustration of this oil-producing mechanism is shown in Fig. 1. As the pressure in the sand declines due to oil production, a predominantly vertical pressure gradient develops at the sand-shale boundary. This causes water to move from the shale into the sand as indicated by the solid arrows.
This paper reports the results of scaled flow-model tests to investigate the efficiency of oil displacement by the vertical influx of shale water into producing sands.
Engineering the Oil Loan
Authors: Sonosky Jerol M. 
Published: June 2014

Introduction
Several discussions have appeared in the literature recently regarding the data required and the factors involved in determining the amount of money which a bank may loan on oil and gas production. The purpose of this paper is to present the actual mechanics of applying these factors, pointing out their importance in the determination of loan value. The required data and applicable factors will be presented, including a step-by-step analysis of the procedures to be used. Also, examples will be discussed to present the type of results obtained and decisions required for loan analyses at various stages of reservoir depletion.
It should be kept in mind that, although the criteria presented are typical, they are by no means final, because the proper solution of the problem involves many variables which may affect each property differently. Furthermore, the actual evaluation may require additional types of analyses other than those presented, depending on the type of loan, operator, property, etc. This discussion is intended as a guide for the engineer whether he works for an operator, consultant or bank - in determining the amount of loan which a given property can safely handle so that he may properly advise his management of the engineering validity of the transaction.
Coking Behaviour During Visbreaking
Authors: Saxena Atul , Diaz-Goano Carolina , Dettman Heather 
Published: June 2014

Summary
Previously, nuclear-magnetic-resonance (NMR) carbon-type-analysis data were used to develop a mathematical model of mild thermal conversion (visbreaking) of Athabasca bitumen (Chan et al. 2006). In that work, the major reaction pathways followed during visbreaking were identified. This approach is being extended in the current work to model the visbreaking behaviour of five different oils from different geographical locations around the world. This paper shows the correlation of residue conversion with the contents of different carbon types for five heavy oils from four continents.
During visbreaking runs, operators intend to maximize process yields. This is achieved through increasing process severity by raising temperature. However, if the temperature is too high, coke forms. This maximum temperature varies with different crude oils; therefore, as refinery feedstock composition changes, so does the onset of coking temperature. Coke is a hydrocarbon material that has low hydrogen content and is insoluble in the oil. Consequently, this precipitates in the reactor, eventually causing an unscheduled unit shutdown. We have found that contents of specific carbon types in the feed oils correlate with coke formation. This correlation allows prediction of the quantities of coke that will form under the chosen visbreaking (mild thermal) conditions and the "maximum" quantities of coke that would form under coking (severe thermal) conditions.
A New (3D MUDSYST Model) Approach to Wellbore Strengthening While Drilling in Depleted Sands: A Critical Application of LCM and Stress Caging Model
Authors: Bassey Akong , Dosunmu Adewale , Iorkam Azoom , Otutu Friday , Ukoha Joshua , Awe Ayodele Sunday , Alabi Tunde 
Published: June 2014

Abstract
With the continued growth of drilling activities and the cost of performing them in depleted sands, loss of productive time is more important than ever. For years the use of LCM has been the preferred way for treating lost-circulation problems (Messenger 1981). However, the lost circulation problem was not totally resolved. Recent studies have shed much light on its cause and potential solutions. However, wellbore strengthening or stress cage implementation has been recognized as an effective means of dealing with lost circulation during drilling operations. One of the mechanisms developed for strengthening a wellbore has been to prop induced and existing fractures with particulate lost circulation materials (LCM) to effectively increase hoop stress in the near wellbore region. However, a good understanding of this mechanism is necessary in order to avoid a potentially flawed design and implementation process which could adversely affect job success during well operations. One of the main issues is depleted sand/shales stringers stability under the strengthening conditions. This paper will describe those factors which are important in designing wellbore strengthening jobs and address the conditions necessary to help ensure depleted sands stability, as determined through geomechanics analysis. The strengthening of a wellbore by propping fractures has been discussed in a previous investigation (Wang et al. 2007a). In this paper, various parameters that affect the strengthening of the wellbore are addressed in detail. In-depth discussion of how each of those parameters affects the process of wellbore strengthening will be presented. This study was accomplished using a boundary element numerical analysis coupled with the linear elastic theorem. Hence, the stress cage concept is an approach developed to enhance wellbore pressure containment (WPC). It has been found that a weak wellbore can contain much higher pressure if the wellbore fluid is treated with particulates and as such understanding the mechanism of stress caging is recommended to design the treatments for specific field application and to advance the development of the technology for application across a wider mud weight window and with a higher success rate while drilling in depleted sands. On-the-fly preventive methods appear to be favored as they cut down on non-productive time and reduce costs in the longer term while drilling in depleted sands as can be seen using the new 3D MUDSYSTTM model.
Replacing ESP and Gas Lift with ESTSP (Electric Submersible Twin Screw Pumps)
Authors: MacNeil David , Dass Pradeep 
Published: June 2014

Abstract
A detailed study and extensive evaluation was done by Talisman Energy to select the best artificial lift solution for the Situche Field in Block 64, Peru. Gas lift, ESP and Hydraulic Lift were studied. However, a New Technology, ESTSP (Electric Submersible Twin Screw Pumps- Multiphase) was selected for these sour, deep and hot wells.
Delivering Consistent Top Quartile Drilling Performance Without Compromise
Authors: Cockram Mark , Christensen Arne Wyller , Thistle Bruce , Boon von Ochssee Willem , Sinet Jean Claude , Hevrøy Frode , Barke Svein Bjarne 
Published: June 2014

Abstract
When the operator embarked on an intermittent 5 well exploration, appraisal and development campaign offshore Norway between 2009 and 2012 using the West Alpha there were many challenges. The rig contract was part of a multi company consortium, the well program was varied, a 3rd generation semi submersible rig was being used and all inclusive operating rates were high at around $1,000,000 per day.
Following and expanding upon the management principles previously employed 1, the lead operator identified an opportunity to leverage the consortium program and develop a strong relationship with the service companies, in particular the rig contractor.
Health, Safety, Security and Environment (HSSE) was a key driver and over 1000 rig days were delivered without a Lost Time Incident (LTI). The lead operator was able to harmonise and standardise procedures used on every well, regardless of who operated the rig. This enabled a much clearer and more consistent message to be delivered to the work environment.
This paper will outline the management process taken by the operator and contractor that enabled the following performance to be delivered:
1000 days LTI free rig operations. Record setting drilling performance with improvements up to 40%. No damage to the environment.
This paper will also describe how the principles have been transferred to other parts of the operators & contractors organisations.
Real-Time Evaluation of Hole Cleaning Conditions Using a Transient Cuttings Transport Model
Authors: Cayeux E. , Mesagan T. , Tanripada S. , Zidan M. , Fjelde K. K. 
Published: June 2014

Abstract
During a drilling operation, real-time analysis of surface and downhole measurements can give indications of poor hole cleaning. However, it is not always intuitive to understand how and where the cuttings are settling in the borehole, because the transportation of cuttings and the formation of cuttings beds are largely influenced by the series of actions performed during the operation. Using a transient cuttings transport model, it is possible to get a continuously updated prognosis of the distribution of cuttings in suspension and in beds along the annulus. This information can be of prime importance for taking decisions to deal with and prevent poor hole cleaning conditions.
A transient cuttings transport model has been obtained by integrating closure laws for cuttings transport into a transient drilling model that accounts for both fluid transport and drill-string mechanics.
This paper presents how this model was used to monitor two different drilling operations in the North Sea: one using conventional drilling and one using MPD (Managed Pressure Drilling). Some unknown parameters within the model (e.g. the size of the cuttings particles) were calibrated in order to obtain a better match with the top side measurements (cuttings flowrate, active pit reduction due to cuttings removal). Using the calibrated model, the prediction of cuttings bed locations were confirmed by actual drilling incidents like pack-offs and overpulls while tripping out of hole.
Based on the calibrated transient cuttings transport model, it is thereby possible to evaluate what adjustments of the drilling parameters are necessary to stop and possibly remove the cuttings beds, therefore giving the drilling team the opportunity to take remedial and preventive actions based on quantitative evaluations, rather than solely upon the intuition and experience of the decision makers.
Use of Electromagnetic Surveys to Monitor Removal of an Oil Field Produced Water Plume, East Poplar Oil Field, Eastern Montana
Authors: Jacobs Michael , Smith Bruce , Tyrrell Christa 
Published: June 2014

Abstract
In 1999 Pioneer Natural Resources (PNR) was notified that a plugged and abandoned well, the Mesa Biere #1-22 (now Pioneer), operated by Mesa Petroleum and plugged in 1986, appeared to have been improperly plugged and had released chloride-rich oilfield brine into the shallow aquifer.
Pioneer Natural Resources voluntarily designed and built a plume capture and remediation system consisting of thirteen "brine", groundwater removal wells, five crude oil recovery wells and a deep, 7,800 foot, USEPA Class V, injection well. The brine remediation system became fully operational in August 2008 and is operating at an average daily rate of 5,100 barrels per day (214,200 gallons/day). As of December 2012 the system has removed 5,402,739 barrels (226,915,038 gallons) of brine contaminated water with an average concentration &gt;20,000 mg/L Chlorides.
An airborne frequency domain helicopter EM survey flown by the USGS in 2004 mapped the subsurface conductivity of the SE part of the Poplar Oil Field. This survey provided a hydrogeologic framework and plume mapping over a large area. In the Biere #1-22 area Pioneer Natural Resource personnel have conducted more detailed ground EM surveys with a loop-loop EM 34XL system with separations of 10, 20, and 40 meters. These surveys were used in conjunction with water well sampling to develop an estimate of the extent of the brine and crude oil plumes in the Mesa Biere #1-22 area.
Traditional monitoring of plume removal efficiencies depends on groundwater sampling of wells within the plume area and related interpretations of the spatial and temporal changes of the plume are restricted to interpolated data between monitor well locations. The usefulness of the EM surveys are that they are inexpensive and easy to conduct and can give useful information over a much more detailed area within the plume. The Biere #-22 survey consists of 237 stations over a 1.03 mi2 grid on 300 ft and 400 ft spacing. The survey is approximately 16 linear miles. A unique aspect of the ground geophysics has been that the repeated EM34XL surveys conducted since system turn-on shows decreases in the area of high subsurface conductivity that correlates with a decrease in the area of the plume geometry.
Remediation of Contaminated Water Using Heterogeneous Catalyst: A Preliminary study
Authors: Asuelimen L. I. , Huddersman K. 
Published: June 2014

Abstract
PAH-contaminated water containing benzo (a) pyrene (Bap) was treated by oxidative catalytic decomposition using a heterogeneous fibrous (polyacrylontrile-PAN) catalyst in a modified Fenton reaction. This attempted to ameliorate the challenges of conventional homogeneous catalytic method using Fenton reagent in soil and groundwater treatment which is limited by natural processes such as pH buffering, iron precipitation, and the need for recovery of iron in the homogeneous catalyst to comply with environmental regulations. For this purpose several bench scale tests were performed, with hydrogen peroxide and modified PAN catalyst. Optimum reaction conditions were investigated by varying H2O2 concentrations, heterogeneous PAN catalyst, contaminant concentration, and pH. BaP concentration was determined using HPLC. The Fenton-like oxidation was efficient at pH 4-5, neutral, and even above neutral, with degradation efficiencies of 84–100%. With the optimization of the working scale for the catalysis, the optimum condition for the degradation of 0.1 mg/L of BaP in water matrices (50 mg/L H2O2, 2g PAN catalyst, pH 4.5, at normal room temperature) could completely break down BaP in 45 minutes. There was no significant difference in activity of the catalyst after using to fresh feed for seven cycles reflecting the stability and reusability of the PAN catalyst, an indication of its potential use in continuous processes. The overall result indicate that oxidative catalytic decomposition using a heterogeneous fibrous (polyacrylontrile-PAN mesh) catalyst would have a promising application to site remediation.