bluuebunny/crossref_metadata_2025 huggingface dataset:
Screening Potential Production Technologies for the Lower Fars Heavy Oil Asset in Kuwait
Authors: Oskui G. P. , Al-Naqi A. , Dusseault M. B.
Published: December 2009

The Lower Fars (LF) sandstone reservoir in Northern Kuwait( NK) is probably the single largest accumulation of heavy oil (HO, μ > 100 cP) in Kuwait, containing somewhere in the range of 12-15 Bb distributed over an area of ~1000 km2 northwest of Kuwait City against the Iraqi border. There are other heavy oil accumulations in Kuwait, mainly in naturally fractured carbonate strata, but they are of smaller size and of lower quality. Although a small resource in comparison to Canadian and Venezuelan HO resource, the Lower Fars reservoir nonetheless represents a significant fraction of Kuwaiti resources.

Compared to viscous oil deposits elsewhere in the world, the LF asset is shallow, of generally higher porosity and permeability, and of lower viscosity with a significant variation in fluid properties with depth and with location in the large reservoir. These characteristics will lead to the deployment of a number of production technologies similar to but somewhat different from Canadian experience, with the potential for generally greater recovery factors and lower costs than in Canada. Furthermore, a general situation is emerging in the Kuwait region that may be unusually favorable for heavy oil development, and these positive factors include: Availability of diluents and natural gas for production process,Capital availability for upgrading investment,Sources of low-cost heat.

This confluence of excellent reservoir properties, existing commercialized technologies with a reasonable history of commercialization, a good infrastructure, and supportive emerging supportive conditions will make the development of the LF a less costly venture than comparable cases in Canada and Venezuela.

In this paper the latest studies in reservoir evaluation and various screening techniques for selection of optimal production technologies will be presented. We will revisit the concept of deliberate sequencing of processes, planning in advance for such strategies. We will even speculate on how local heat sources might be integrated into production processes.
Hydrate Problems in Gas Lift Production: Experiences and Integrated Inhibition
Authors: Nengkoda Ardian , Reerink Hendrikus , Hase Alfred , Supranto Supranto , Prasetyo Imam , Purwono Suryo , Budhijanto Budhijanto
Published: December 2009

Currently, there are more than 10 oil producing station, in both North and South area operation of Petroleum Development Oman, which facing a unique gas hydrate problems. Most of these wells are producing by the support of gas lift. Therefore, it is very important that the gas lift network is kept optimally operating to maintain the intended production. The ambient temperature in Sultanate of Oman desert drops to as low as 5°C during the coldest 3 months in winter, when hydrates form in several gas lift lines. This causes affected wells to cease production and results in unscheduled deferment. So far, the problem was partly controlled by the use of methanol as hydrate inhibitor (a proven method used worldwide to restrict gas hydrate formation), however there are resulted many issues mainly HSE associated with the use of methanol. The main objectives of this project are to look the other chemicals alternative as hydrate inhibitor – move from methanol to another cost effective and safe chemical inhibitor and the goal is to ensure that the system is adequately inhibited against hydrate formation and that inhibitor injection is optimized. The second goal is to develop a warning system should hydrate start to form (prior to hydrate build up and pipeline blockage). The paper also defines laboratory testing as mandatory requirement to test an alternative hydrate inhibitor and practical facilities up grade.
Comparison Study of Models for Calculating Absolute Permeability Using Nuclear Magnetic Resonance Imaging Log Technology in Tight Sandstone Gas Zones
Authors: Xiao Liang , Mao Zhi-qiang , Wang Zhao-nian , Jin Yan , Liu Xing-gang , Xie Bing
Published: December 2009

Tight sandstone gas zones displayed such characteristics as low porosity and low permeability. At present, it was a challenge for log analysts to gain reservoir absolute permeability precisely in such zones because of the poor correlation between formation porosity and permeability parameters. Classical SDR model and Tim-Coates model from nuclear magnetic resonance (NMR) log data also losed their advantage. In this condition, 21 core samples were chosen to run mercury-injection and NMR log experiment simultaneously, whose porosity ranged from 2.7% to 16.1% and permeability ranged from 0.019 × 10−3μm2 to 131.0 × 10−3μm2. With the analysis of mercury-injection data, correlations were established between rock absolute permeability and the pore structure parameters, such as the average pore throat radius. The inflexion parameter of capillary pressure curves (the Swanson Parameter) was also associated with the rock absolute permeability. By using these relationships, the rock permeability could be calculated from mercury-injection data. Considering the problem that mercury-injection capillary pressure data was limited by their quantity because of the expensive test cost and the environmental concern, based on the fact that NMR T2 distribution and mercury-injection capillary pressure curves all reflected reservoir pore structure, two novel models were established to gain the average pore throat radius and the Swanson parameter from nuclear magnetic resonance T2 distribution. So, these parameters could be calculated from NMR imaging log data and then rock absolute permeability could be gained respectively by combining NMR total porosity. It had demonstrated that these clues could be expandeded to reservoir conditions, and then reservoir absolute permeability could be calculated along the intervals with NMR imaging measurement. At last, an in-situ example from southwest oil and gas field of China was exhibited of calculating reservoir absolute permeability consecutively in tight sandstone gas zones by using these two models and the validity of these models were compared. The Swanson parameter model was suggested in calculating reservoir absolute permeability in this paper. The result shown that absolute permeability calculated by using the Swanson parameter model matched much better with core data than the average pore throat radius model.These two models were also effective and accurate in detecting the thin sand with high porosity and high permeability because a core sample used in these models came from these zones.
Foam Assisted Enhanced Oil Recovery at Miscible and Immiscible Conditions
Authors: Farajzadeh R. , Andrianov A. , Zitha P. L. J.
Published: December 2009

We report an experimental study of CO2 and N2 foam flows in natural sandstone cores containing oil with the aid of X-ray Computed Tomography. The study is relevant for Enhanced Oil Recovery (EOR). The cores were partially saturated with oil and brine (half top) and brine only (half bottom) to mimic the water-oil transition occurring in oil reservoirs. The CO2 was used either under sub- or under super-critical (immiscible and miscible) conditions, whereas N2 remained subcritical. Prior to gas injection the cores were flooded with several pore volumes of water. In each experiment water flooding was followed by the injection of 1-2 pore volumes of a surfactant solution with Alpha Olefin Sulfonate (AOS) as the foaming agent. We visually show how foam propagates in a porous medium containing oil.

At low-pressure experiments (P=1 bar) in the case of N2, weak foam could be formed in the oil-saturated part. Diffused oil bank is formed ahead of the foam front, which results in additional oil recovery, compared to pure gas injection. CO2 hardly foams in the oil-bearing part of the core, most likely due to its higher solubility. Above critical point (P=90 bar), CO2 injection following the slug of surfactant reduces its mobility in absence oil. Nevertheless, when the foam front meets the oil it becomes highly diffuse. The presence of the surfactant (when foaming super-critical CO2) hardly improves oil recovery and or modifies the pressure drop profile, indicating the detrimental effect of oil on foam stability in the medium in this specific case. However, at miscible conditions, injection of surfactant prior to CO2 injection significantly increases the oil recovery.
Oil Fields Scale Deposition Prediction Methodology
Authors: Refaei M. I. , Al-Kandari I. A/Karim
Published: December 2009

Oilfield scale costs are high because of drastic oil and gas production decline, frequent pulling of down-hole equipment for replacement, re-perforation of the scaling producing intervals, reaming and re-drilling of the plugged oil wells, stimulation of the plugged oil-bearing formation and other remedial work-over. As scale deposits around the well-bore, the porous formation becomes plugged and may be rendered impermeable to any fluids.

In most of oil and gas fields scale deposition in surface and subsurface production equipment has been recognized to be one of the major operational problem. Problem will be more critical in Water flooded fields where wells will suffered from flow restriction because of scale deposition within the oil producing formation matrix and the down-hole equipment, as well as scale deposits in the surface production equipment.

Some of the Oil Fields have been water-flooded with formation seawater. Compatibility tests have indicated probable deposition of scale in surface and subsurface production equipment. This paper outlines the physical and theoretical prediction for down-hole scale deposition in the water flooded fields.

Water is the main substance, which is responsible for scale build up problem. In order to study the circumstances behind the scale build up problem, following the new methodology which can be applied to predict the different types of scale build up before start to be precipitated. From the samples of the complete water analysis reports, Scale Indexes were calculated to define the different scales that can be precipitated at different production nodes/conditions.

This paper showed that different types/amounts of scale accumulation can be precipitated from the selected water samples since the super saturation conditions of water occurred. It also described the control of scale inhibition programs which could be carried out to control down-hole scale deposition and scale inhibition treatment that could be implemented to overcome the scale deposition, before scale problem will be occurred. Scale control can also been controlled/managed properly by continues updating the new scale index calculations methodology described in the probable problematic water flooded reservoir.
Investigation of Cyclic Water Injection after Polymer Flood in Xing4-6 Field, Daqing
Authors: Gao P. , Feng Y. , Zhang X , Luo F
Published: December 2009

Xing 4-6 is a multilayer sandstone reservoir which has already experienced a secondary water flood in the entire reservoir and a tertiary polymer injection in certain formations. The polymer flooding began in 2001 as a typical polymer flooding field in Daqing. Currently,the Xing 4-6 is reaching the end of the designed polymer injection. In this paper, a cyclic water flood after the polymer injection is investigated in this field. The research is principally on the basis of reservoir simulations. After the history matching of the water flooding, a polymer flooding model describing target polymer flooding layer was extracted from the water flooding model to simulate the polymer injection process. By combining the development information and simulation results, the efficiency of the polymer flood was analyzed as the fundamental of cyclic injection investigation. Based on the plenty of geological study and multidisciplinary investigation, a cyclic flooding model describing Putaohua I formation was established.

Two cyclic injection cases were designed. Two cyclic units were defined in the model: the priority payzone P I33was considered as an independent cyclic unit due to its considerable proportion of the original oil in place (OOIP); other six layers were set as the second unit.In one case, the cyclic water was only conducted in the first unit; the other unit still employed continuous water injection. In the other case, two units were alternatingly involved in the cyclic injection. The predictions showed that the vertical sweep efficiency had been improved in upper zones which have vertical connectivity with lower layers due to the pressure pulsation and capillary pumping of the wetting phase in the low-permeability zones, especially the zones with high heterogeneities. Areally, the dead oils which were formed by the un-improvement of injection and production system were also mobilized. The cyclic water injection after polymer flooding improved the ultimate recovery. One more significant advantage was the extended use of the current well pattern. Comparing two cases, the case with only one cyclic unit involved had a better development efficiency in the priority payzone P I33 than that of the case with alternating cyclic injection, the incremental recovery in P I33 was 1.21%, which was 0.37% higher than that of the alternating case. Because the case with alternating cyclic injection took all zones into the consideration, the entire flooding efficiency was better than the other. The incremental recovery of alternating cyclic injection was 0.84% which was 0.32% higher than that of one cyclic unit injection on the reservoir scale. The detailed analysis in each case was also presented.
Depositional Environment and Controls on Porosity Development and Distribution, in the Late Albian Mauddud Formation, Sabiriyah and Raudhatain Fields, Kuwait, as Input to a Geocellular Model
Authors: Brinton Lise , Keay James , May Michael
Published: December 2009

Detailed description of core (19,500 ft) from 57 wells in the Cretaceous (Late Albian) Mauddud Formation, Sabiriyah and Raudhatain Fields, Northern Kuwait, formed the basis for an updated depositional model. Numerous reservoir units occur within carbonate-dominated, mixed carbonate-clastic, and siliciclastic-dominated intervals. Core description and interpretation software (WellCAD/CoreCAD) was used to record observations and interpretations in digital format which was integrated into a master database for geocellular modeling, static, and dynamic reservoir modeling.

The predictive depositional model demonstrates lithofacies distribution, primary depositional and secondary diagenetic controls on porosity occurrence, distribution of high permeability ‘thief zones common in both fields, and distribution of flow baffles and barriers within the vertical sequence.

The Lower Mauddud comprises carbonate-dominated shallowing-upward cycles deposited in a carbonate ramp environment and localized clastic wedge deposits and associated tidal channels. The Upper Mauddud evolved to carbonate platform geometry with bioclastic shoals, rudist banks and patch reefs, and restricted back-reef and lagoonal highstand deposits. Late highstand deposition culminated in widespread subaerial exposure near the top of Upper Mauddud.

Most porosity development and distribution is controlled by depositional fabric and texture, bioturbation, and dissolution during subaerial exposure at cycle tops. Widespread exposure surfaces and related brecciation and dissolution associated with late highstand deposition are major contributors to thief zone development. Several marine flooding events influence widespread and correlative vertical flow baffles.

‘Bank and tidal channel’ topography is dominant in the upper Lower Mauddud, where shoals and patch reefs developed between tidal channels. Tidal channels were filled in part with poor to non-reservoir clastics, creating baffle zones.

Bioclastic shoals comprise Upper Mauddud reservoir units. Middle-late highstand reservoirs are composed of bank crest rudist buildups, patch-reefs and shoals. Late highstand deposits record increasingly restricted depositional setting, increase in frequency and duration of subaerial exposure, and development of karst brecciation with associated dissolution.
Numerical Investigation of Condensate Banking in the North Kuwait Jurassic Gas Condensate Reservoirs
Authors: Tan Leong Hooi , Ghorayeb Kassem , Aziz Rafi M. , Al-Anzi Ealian H.
Published: December 2009

Condensate banking is a much studied phenomenon in gas condensate reservoirs. An excessive drop in flow rate occurs when the bottom hole flowing pressure of a producing well falls below the dew-point pressure. Condensate dropped around the well bore increasingly reduces relative permeability to gas until a critical liquid saturation is reached. As liquid saturation increases above the critical value, two phase flow of both liquid and gas creates the equilibrium necessary to maintain the reduced, but steady state flow. The reduced gas permeability is described as a positive skin reducing the well rate PI used in the forecasts. In more severe cases, the PI may be reduced to cause sub-commercial rates. Even though several equations are available in the literature to estimate skin damage due to condensate banking, it is well recognized that localized reservoir characteristics, especially in naturally fractured carbonates must be applied to obtain an accurate value.

In this paper, numerical inverstigations of the impact of condensate banking on well productivity in the North Kuwait Jurassic Complex (NKJC) gas-codensate reservoirs are performed. A representative reservoir from Sabriyah field in the Najmah Sargelu formation was selected for the purpose. A general equation thus developed for rich condensate gas in naturally fractured carbonates was applied to the complex of reservoirs existing in the NKJC to study the impact condensate banking of full field performance.
A Pore Network Modelling Method to Predict the Flow Parameters in Loose Sandstone
Authors: Du Zhimin , Yong Deng , Chen Zhaohui
Published: December 2009

Loose core and sanding make it very difficult to carry out core experiments for acquisition of the flow parameters including capillary pressure and relative permeability. Studies on pore network models available in literature are not generally considering the influence of stress sensitivity and clay swelling which are studied as the main factors affecting the flow parameters. Firstly, a three-dimensional pore network model from the digital core is used to calculate the flow parameters. Secondly, on the basis of pore network theory, combined with the study of stress sensitivity and clay swelling, a series of dynamic models are established, which are used to describe the variations of pore microscopic parameters. At last, the flow parameters under different conditions were simulated through programming in MATLAB.

From this study, some results and conclusions can be obtained as following: Because of stress sensitivity and clay swelling, the pore microscopic structure is changed. The pore shrinks, the shape factor reduces and the pore-throat ratio along with coordination number also decrease. These variations cause capillary pressure to increase and the relative permeability curve shifts to the right.At the early period of the exploitation, stress sensitivity and clay swelling all make contributions to the changes of the flow parameters, but at the later stage, the effect of clay swelling could be faded to vanish because the clay has been saturated with water.With the increase of effective stress and the effect of clay swelling, the wetting phase's relative permeability increases but the nonwetting phase's relative permeability declines. This is mainly because of the pore's shrinkage that makes the whole flow ability of the fluid decreasing. But the non-wetting phase occupies the middle of pore throat and the pore wall makes little influence on it, inversely, its capacity of relative movement could increase.
Flow Unit Thickness and Permeability Evaluation in Horizontal Wells Using Logging While Drilling and Wireline Formation Tester Transient Data
Authors: Cig Koksal , Ayan Cosan , Al-Mahrooqi Sultan , Al-Shamsi Khalsa
Published: December 2009

Oil was discovered in a carbonate reservoir which indicated discontinuous and complex geological features. The carbonate field in the Sultanate of Oman is at the early stages of development and reservoir uncertainties are still significant.

The uncertain geological features, proximity of possible faults and heterogeneous reservoir properties make horizontal well placement a difficult task. The latest logging while drilling (LWD) technology for well placement was utilized to track the distance to the upper flow unit of the reservoir. It was discovered that the formation was dipping upwards and had separate units. The lower flow unit boundary was uncertain due to the LWD distance detection limit. Flow unit thickness identification became an important task to understand the potential of the reservoir. The objective of this study in the complex reservoir is to present a new way to determine the flow unit thicknesses by utilizing the LWD and wireline formation tester (WFT) interval pressure transient tests (IPTT) data.

IPTT tests with a dual inflatable packer in combination with LWD logs resulted in local horizontal and vertical permeabilities and flow unit thicknesses along the horizontal well. Integration of the two distinct logging methods helped accomplish not only the well geometry and local petrophysical properties, but also gave information on large scale properties. The wells were also surveyed with open hole logging tools to obtain sedimentary features, to collect necessary oil samples and to obtain reservoir properties such as faults information, saturations, permeabilities and in-situ rock stresses. Following data acquisition and joint evaluation, an integrated study was conducted for the field development.

This paper presents an integrated solution of LWD logs and IPTT data evaluation. The approach had a considerable impact on field development plans and reserve calculations in the new and complex carbonate reservoir.
Maximizing Coiled Tubing Reach during Logging Extended Horizontal Wells Using E-line Agitator
Authors: Al-Buali Muhammad H. , Dashash Alaa A. , Shawly Alaa S. , Al-Guraini Walid , Bugrov Vsevolod , Nicoll Scott
Published: December 2009

The implementation of extended reach horizontal wells in Saudi Aramco, and in the southern area of Ghawar field in particular, is being increased for production and cost optimization. Logging these wells is a challenge, as production profile of a horizontal section cannot be entirely recorded with conventional coiled tubing (CT). This is mainly because of friction forces between the CT and the wellbore, which cause CT to lock-up significantly shallower than total depth (TD). Although with availability of this limited technique, such as metal to metal friction reducer, still CT reach cannot be maximized effectively.

This paper will describe a successful utilization of agitator tool with custom designed e-line bypass that helps CT maximize the coverage of the horizontal section for logging purposes. The agitator tool was incorporated into the Production Logging Tool (PLT) and bottom-hole assembly (BHA). It was activated by pumping to cause the CT string to vibrate, and subsequently reduce the friction contact between the CT and the wellbore to allow CT running beyond the normal lock-up depth.

The tool was trial tested in an extended reach horizontal well which has a TD of 12,118 ft. The simulator was showing a predicted lock at 10,400 ft while a dummy run proved a lock-up point occurs at 10,800 ft without activating the agitator. The e-line agitator was activated while the well was flowing at a restricted rate which maximized the reach to the TD and reducing the friction coefficient by around 26%. Different conditions and parameters were conducted in order to understand the best performance of the e-line agitator tool.

The implementation of the e-line agitator resulted in extending the reach of CT by an additional 1,300 ft and reaching TD. This additional reach was significant as the last part of horizontal section was contributing water. The production log has been reviewed and showed acceptable measurements. This paper will cover the whole cycle of candidate selection, job design, execution, post job evaluation, lessons learned and conclusion.
Two stages Cutting Structures of Bi-center PDC Bit provides two phases of Destroying Volume of the Rock, Results Faster Penetration Rate through Deep Section of Carbonates Formation in Kuwait
Authors: Hendrazid Hendrazid , Behbehani Masoud , Al-Khaldy Meshal Dawood , Esmaiel Ahmad
Published: December 2009

To drill deepening hole below 7" liner through deep section of compact interbedded carbonate formation results slow rate of penetration (ROP). Beside the limberness of BHA configuration (which is stiffer for the larger sizes of BHA) thus generates various string vibrations, the used of heavier mud weight can also effect overbalance pressure thus reduces drilling ROP.

This paper outlines the two stages diameter PDC bit, that proficiently increases drilling efficiency in order to produce faster ROP through small hole, deep section drilling. When the PDC bits cutting structure is separated into two stages of hole diameters, the mechanical energy that is required to destroy a given volume of the rock to drill can be significantly reduced. This energy reduction can be equivalent to the percentage of the hole size reduction relative to the final hole diameter. The reduced hole diameter that is described as pilot hole will be drilled by the first stage of the bit. The second stage of the bit that is called as reamer section simply enlarges a stress relieved pilot hole, to a final hole diameter.

The Mechanical Specific Energy (MSE) concept that is defined as work that is required to fail a given volume of rock has been formulated proportionally with formation rock strength. MSE can also be defined as input energy to result ROP. The ROP to drill a smaller hole is faster than ROP to drill larger hole although with similar BHA, whilst ROP to enlarge a pilot hole always faster than ROP to drill the pilot hole.

Because the bi-center bit has a pilot section that can be used for drilling a smaller pilot hole and a reamer section for enlarging pilot hole to a final hole size, therefore it shoud be able to produce faster ROP compared to conventional one stage PDC bit. The field results revealed that all of 5-3/4" × 6-1/2" and 6" × 7" bi-center bits that were run below 7" casing by Kuwait Oil Company in Kuwait - through deep wells, have drilled the intervals more than 30% faster than conventional PDC bit.
Inflow Performance of Cyclic Steam Stimulation using Horizontal Well
Authors: Wu Z. , Vasantharajan S. , El-Mandouh M. , Suryanarayana P. V.
Published: December 2009

In this paper we present a new, semi-analytical gravity drainage model to predict the oil production of a cyclic steam stimulated horizontal well. The underlying assumption of the effort is that the cyclic steam injection creates a cylindrically-shaped steam chamber in the upper area of the well. Condensed water and heated oil in the chamber are driven by gravity and pressure drawdown towards the well. The heat loss during the period of soak and oil production is estimated by vertical and radial conduction means. The average temperature change in the chamber during the cycle is calculated using a semi-analytical expression. Nonlinear, second order ordinary differential equations are derived to describe the pressure distribution caused by two phase flow in the wellbore. A simple iteration scheme is proposed to solve these equations. The influx of heated oil and condensed water into the horizontal wellbore is calculated under the assumption of steady-state radial flow.

The solution from the semi-analytical formulation is compared against the results from a numerical thermal simulator on an example. The results are in good agreement with those obtained by the reservoir simulator. Sensitivity studies for optimization of wellbore length, gravity drainage, bottom-hole pressure, and steam injection rate are conducted with the model. Results indicate that the proposed model can be utilized in optimization of individual well performance in cyclic steam heavy oil development. The suggested semi-analytical thermal model can offer an attractive alternative to numerical simulation for planning heavy oil field development.
Application of Horizontal Wells for Injection or Production During Polymer Flood Processes
Authors: Lee Kun Sang
Published: December 2009

Laboratory investigations and field applications have proved injection of polymer solutions to be an effective means to improve oil recovery for reservoirs of medium oil viscosity. This numerical study was undertaken to investigate and compare the performances of polymer flood processes through horizontal and/or vertical wells. To achieve the object of this study, an extensive numerical simulation was performed for three different well configurations under polymer flood followed by waterflood.

A three-dimensional numerical model for fluid flow and mass transport is used to analyze the performance of the reservoir. The potential for a horizontal well application was assessed through different scenarios in combinations of injection and production wells and reservoir geometry. Other parameters include the length and spacing of horizontal injectors and horizontal or vertical producers. For different parameters of the system, performances were compared in terms of cumulative recovery and water-oil ratio at the production well and pressure drop or injectivity at the injection well.

Results from the study have demonstrated that additional oil can be recovered and injectivity was significantly improved by utilizing a combination of horizontal wells when the same volume of fluid is injected into the reservoir. The improvement of injectivity through a horizontal injection well was higher when it was combined with horizontal producer. Parameters such as reservoir thickness, well spacing, and well length are also shown to impact the predicted injectivity. Improvement in injectivity is obtained for thicker and larger reservoirs and longer horizontal wells.
Parametric Study of Gas Condensate Flow in Naturally Fractured Reservoirs
Authors: Alajmi E. , Jamiolahmady M. , Sohrabi M.
Published: December 2009

Naturally fractured carbonate reservoirs (NFRs) are usually characterized by complex pore systems that significantly affect the rock flow properties. Such reservoirs gained a wide interest and intensive research in the petroleum industry due to the challenges it poses in term of reservoir performance modeling. The presence of retrograde fluid in gas condensate systems, when the pressure drops below dew point, adds further complexity to the performance of NFRs. There are limited publications dealing with gas condensate flow in NFRs and the impact of variation of relative permeability with velocity and interfacial tension have so far not been studied.

In this work dual porosity option of the ECLIPSE 300 compositional reservoir simulator, which includes our in-house relative permeability (kr) correlation accounting for the positive coupling (increase in kr by an increase in velocity and/or decrease in interfacial tension) and the negative inertial (decrease in kr by an increase in velocity) effects, has been used to conduct a series of sensitivity analysis on a single-well model. The impact of pertinent parameters; including fracture width, fracture relative permeability, fluid richness, coupling and inertia have been studied. The effect of critical condensate saturation on final recovery due to gravity drainage mechanism was also studied.

The results demonstrated that positive coupling seemed to be more dominant in our study. Also, assigning unrealistic high critical condensate saturation could lead to significant underestimation of condensate recovery, especially in gravity dominated conditions. Nevertheless, the use of straight line relative permeability could lead to numerous errors in performance prediction.
Real-Time Imaging and Monitoring of Drilled-Cuttings Averting ‘Drillstring Stuck-Ups’
Authors: Limkar Parikshit S.
Published: December 2009

Drilled-cuttings circulated by drill-mud through the wellbore, while drilling is in progress, can be a clue to many inimical circumstances such as the ‘mechanical sticking of the drill-string’, ‘presence of abnormal pressure zone or gas bearing zone’ etc. If the cuttings are accumulated around the BHA, in the section of hole being drilled, owing to the contexts, such as, ‘insufficient mud annular velocity’, ‘improper composition of the mud’ or ‘increased penetration rate’, it leads to ‘drill-string stuck-up’ which can cost a substantial amount of money. This paper proposes a novel technique, which can generate and transmit the real-time images of wellbore around the BHA, thus, enabling real time monitoring of the flow path of freshly drilled cuttings, being flushed and circulated out by drill-mud. Real-time images of ‘the area around BHA’, facilitates live monitoring of well cuttings, thus, provide a valuable information regarding cuttings that are being accumulated around the BHA. The produced thermal images of ‘generated cuttings’ can provide valuable input for the selection of certain drilling parameters, such as, type of bit to be used, ‘equivalent circulation density & viscosity of mud’ to be maintained etc., thus, enhahancing the efficiency of drilling-mud circulation system.
Core Scale Fracture Characterisation in Deviated Wells Aid Multiple Jurassic Reservoir Development in Minagish Field, West Kuwait
Authors: Verma Naveen Kumar , Al Shamali Adnan Aiesh , AL-Mayyas Eman Abdullah , Dasma Mohammed , Al-Khamis Waleed Khamis
Published: December 2009

Unconventional fractured Najmah-Sargelu (NJ-SR) and tight carbonates of Middle Marrat constitute Jurassic reservoirs in Minagish Field. Although NJ-SR oil was discovered in mid-eighties, reservoir development remains a challenge in this field where exploratory delineation wells have been drilled until 2002. The reservoir characterisation difficulties in this unconventional fractured reservoir include large well spacing, field compartmentalization, low resolution seismic and oil based well logs besides drilling problems. Therefore, understanding of the productivity controls is primarily based on the image logs and core data collected in vertical exploratory or Marrat development wells. Based on these data in Minagish and adjoining fields, supplemented with seismic facies analysis for identifying sub-seismic ‘fracture corridors’, a regional 3D Discrete Fracture Network model (DFN) was built for West Kuwait in 2004. It thus became feasible to place a Marrat well through NJ-SR fractured area or even to intercept a fracture corridor using a deviated well profile. Yet, since the model was largely conceptual, a quantitative validation was planned through acquisition of NJ-SR core in such wells, followed by core orientation using Goniometry technique and detailed core to image log fracture calibration to understand relationship between large and small scale features and their role in productivity.

First such deviated well was successfully drilled near a fracture corridor and cored using ‘half-moon’ core barrel technology despite repeated core jamming. Core was oriented using goniometry technique and striking parallelism was observed between the image log based and core based fractures. However, the well could not be tested in NJ-SR and was completed in Marrat based on reservoir considerations. Similar core-based fracture characterization was successfully done in second such deviated well that traversed through a deformation zone further away from a fracture corridor. The well has recently been tested and produced oil from NJ-SR reservoir fulfilling combined objectives of appraisal and development of multiple Jurassic reservoirs. Present paper provides a detailed account of these fracture characterization efforts through goniomentry and core to image log calibration for understanding the productivity controls, and discusses further well design optimization possibilities.
Interaction Between Flexible Risers and Mooring Lines within a Floating Production System
Authors: Brown Paul Anthony , Larsen Ian , Chandwani Ramesh , Dasambiagio Evandro Rossi
Published: December 2009

In any semisubmersible-type or turret-moored tanker-type floating production system (FPS) it is essential to consider interaction between the flexible riser system and mooring system or anchor spread. This is necessary in order to ensure that there is adequate clearance between mooring lines and the closest riser at all depths and that cross-over of lines is avoided. This is a particular problem in supergiant fields utilising many flexible risers, for example the large Campos Basin fields offshore Brasil. Furthermore, a quantitative evaluation of the total dynamic load imposed on the vessel due to the riser system is required for assessment of station keeping and stability and for structural design.

This paper demonstrates simultaneous dynamic analysis of flexible riser and mooring systems for a complete FPS. The FPS studied uses a semisubmersible type vessel located in deep water. The vessel is kept on station using a 12-point mooring system. The riser system utilises flexible pipe technology and all risers are designed using a "lazy wave" configuration. The system is subjected to both operational and extreme wave conditions. The effect of variable current direction with depth, which is common offshore Brasil, is demonstrated. The coupled effect of pipe-seabed friction is also demonstrated.
The Winter Walkability Project: Occupational Therapists' Role in Promoting Citizen Engagement
Authors: Ripat Jacquie D. , Redmond Judy D. , Grabowecky Bill R.
Published: December 2009

Background. Walkability is one feature of a person-friendly community that citizen engagement can influence. Purpose. Describe a winter walkability project and how an occupational therapist supported citizen engagement and participation in local policy decision making. Methods. Seven stakeholder representatives undertook a participatory research project to address winter walkability. Through focus groups and walking logs, 10 citizens provided feedback on barriers to winter walking and a new sidewalk snow-clearing method. Analysis ascertained factors contributing to winter sidewalk walkability and factors promoting citizen engagement. Findings. Results identified reasons for and barriers to walking, perceived reasons for sidewalk conditions, and perceived effectiveness of the snow-clearing intervention. Citizens recommended against using the new snow-clearing method. Factors promoting citizen engagement included individual actions producing nominal results, individual and community-level interest, and development as citizen-experts. Implications. This project provides one example of how occupational therapists can take a sociopolitical role and facilitate citizen and occupational engagement.
Re-Examining Concepts of Occupation and Occupation-Based Models: Occupational Therapy and Community Development
Authors: Leclair Leanne L.
Published: December 2009

Background. A growing body of literature supports the role of occupational therapists in community development. Using a community development approach, occupational therapists respond to community-identified occupational needs. They work to build local resources and capacities and self-sustaining programs that foster change within the community and potentially beyond. Purpose. The purpose of this paper is to highlight some key issues related to occupational therapy practice in community development. Key Issues. The definitions and classifications of occupation focus primarily on the individual and fail to elaborate on the shared occupations of a community. As well, occupation-based models of practice are not easily applied to occupational therapy practice in community development. Implications. In order for occupational therapy to articulate its role in community development, greater heed needs to be given to the definition and categorization of occupation, occupation-based models of practice, and their application to communities.
Coyote Habitat Selection and Management Implications for the Gaspésie Caribou
Authors: BOISJOLY DOMINIC , OUELLET JEAN‐PIERRE , COURTOIS RÉHAUME
Published: December 2009

ABSTRACT Anthropogenic disturbances can promote establishment and growth of predator populations in areas where secondary prey can then become threatened. In this study, we investigated habitat selection of eastern coyotes (Canis latrans), a relatively new predator in the vicinity of an endangered population of caribou (Rangifer tarandus caribou). We hypothesized that coyotes in the boreal forest depend mainly on disturbed habitat, particularly that of anthropogenic origin, because these habitats provide increased food accessibility. Coyotes would likely take advantage of moose (Alces alces) carcasses, berries, and snowshoe hares (Lepus americanus) found in open habitats created by logging. To test these predictions, we described coyote diet and habitat selection at different spatial and temporal levels and then compared resource availability between habitats. To do so, we installed Global Positioning System radiocollars on 23 individual coyotes in the Gaspésie Peninsula, eastern Québec, Canada. Coyotes selected clear‐cuts of 5–20 years and avoided mature coniferous forests both at the landscape and home‐range levels. Clear‐cuts of 5–20 years were found to contain a high availability of moose carcasses and berries, and vulnerability of snowshoe hares is known to increase in clear‐cuts. The importance of these 3 food resources was confirmed by the characteristics of core areas used by coyotes and diet analysis. Moose remains were found at 45% of core areas and coyote diet comprised 51% moose on an annual basis. Anthropogenic disturbances in the boreal forest thus seem to benefit coyotes. Our results indicated that the relationship between coyotes and caribou likely involves spillover predation. This knowledge allows managers to consider spillover predation by coyotes as a possible threat for endangered caribou population when the predator depends mainly on habitat of anthropogenic origin and to suggest methods to alleviate it when developing management plans.
Yearling Greater Sage‐Grouse Response to Energy Development in Wyoming
Authors: HOLLORAN MATTHEW J. , KAISER RUSTY C. , HUBERT WAYNE A.
Published: December 2009

ABSTRACT Sagebrush (Artemisiaspp.)‐dominated habitats in the western United States have experienced extensive, rapid changes due to development of natural‐gas fields, resulting in localized declines of greater sage‐grouse (Centrocercus urophasianus) populations. It is unclear whether population declines in natural‐gas fields are caused by avoidance or demographic impacts, or the age classes that are most affected. Land and wildlife management agencies need information on how energy developments affect sage‐grouse populations to ensure informed land‐use decisions are made, effective mitigation measures are identified, and appropriate monitoring programs are implemented (Sawyer et al. 2006). We used information from radio‐equipped greater sage‐grouse and lek counts to investigate natural‐gas development influences on 1) the distribution of, and 2) the probability of recruiting yearling males and females into breeding populations in the Upper Green River Basin of southwestern Wyoming, USA. Yearling males avoided leks near the infrastructure of natural‐gas fields when establishing breeding territories; yearling females avoided nesting within 950 m of the infrastructure of natural‐gas fields. Additionally, both yearling males and yearling females reared in areas where infrastructure was present had lower annual survival, and yearling males established breeding territories less often, compared to yearlings reared in areas with no infrastructure. Our results supply mechanisms for population‐level declines of sage‐grouse documented in natural‐gas fields, and suggest to land managers that current stipulations on development may not provide management solutions. Managing landscapes so that suitably sized and located regions remain undeveloped may be an effective strategy to sustain greater sage‐grouse populations affected by energy developments.
Identifying Hot Moments in Road‐Mortality Risk for Freshwater Turtles
Authors: BEAUDRY FREDERIC , DEMAYNADIER PHILLIP G. , HUNTER MALCOLM L.
Published: December 2009

ABSTRACT Risk assessments can be used to identify threats, which vary both in space and time, to declining species. Just as hot spots describe locations where threat processes operate at a higher rate than in surrounding areas, hot moments refer to periods when threat rates are highest. However, the identification of hot moments can be challenging because the temporal complexity of some threat processes makes their effects on population viability difficult to predict. Declining throughout much of their range, Blanding's turtle (Emydoidea blandingii) populations are potentially most vulnerable to road mortality where road densities and traffic volumes are high. The temporal variations in road‐mortality risk faced by these and other semiaquatic turtles at the population level are a consequence of several factors, including sex‐specific movement characteristics and seasonal changes in traffic volume. We examined these risk factors for Blanding's turtle populations in Maine, USA, by integrating temporally explicit roadkill probabilities with demographic parameters informed by local and range‐wide studies. Specifically, we used population simulations to estimate the relative risk for 14 2‐week periods during the turtles’ active season. Our analysis clearly identified early summer as a period of elevated risk, with June through mid‐July signaling a road‐mortality hot moment for Blanding's turtles (for both M and F). These findings provide guidance for the implementation of temporally explicit conservation measures such as cautionary road signage, traffic management, and public outreach that, if timed strategically, could help to mitigate population impacts from road mortality.
Technique, Safety, and Efficacy of Intra‐Abdominal Transmitters in Nine‐Banded Armadillos
Authors: HERNANDEZ SONIA M. , GAMMONS DANIEL J. , GOTTDENKER NICOLE , MENGAK MICHAEL T. , CONNER L. MIKE , DIVERS STEPHEN J.
Published: December 2009

ABSTRACT  The future management of nine‐banded armadillos (Dasypus novemcinctus) requires solid space‐use and activity data, which are currently lacking and which radiotelemetry can provide. External radiotransmitters have not been successful applied with this species. To make recommendations for intra‐abdominal radiotransmitter placement in nine‐banded armadillos, we 1) evaluated 4 different anesthetic protocols for safety, efficiency, and cost‐effectiveness; 2) evaluated a surgical technique for the intra‐abdominal placement of radiotransmitters that addresses problems described in previous studies; and 3) evaluated the physiologic and behavioral effects of such a technique. We captured and surgically implanted 37 nine‐banded armadillos using either butorphanol and isoflurane, ketamine alone, ketamine and xylazine, or a combination of butorphanol, ketamine, and medetomidine for anesthesia. We recovered and necropsied armadillos after the completion of the study. The objective and subjective assessment of butorphanol, ketamine, and medetomidine combination protocol, followed by reversal of the anesthesia with atipamezole, showed that it was the best overall anesthetic protocol for field use, providing both a smooth induction and fast recovery. We evaluated the fate and effects of radiotransmitters on 13 recovered animals at the end of the study and found no adverse effects. We recommend the implantation of radiotransmitters that are allowed to free‐float within the abdominal cavity and specifically emphasize the need for strict aseptic technique. Wildlife managers and wildlife veterinarians aiming to implant nine‐banded armadillos with radiotransmitters will benefit from using the recommended anesthetic protocol and surgical technique in future studies.