bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

AbstractOil 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

Abstract
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

Abstract
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

AbstractIn 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

Abstract
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

Abstract
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

Abstract
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.