bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Super High Density Drilling Fluid under Ultra-High Temperature on Well Shengke-1
Authors: Yu-zhi Xue , Gong-rang Li , Bao-feng Liu , Zhang Jinghui 
Published: July 2010

Abstract
The Well Shengke-1 is one of ultra-deep wells with total depth of 7026m, bottom hole temperature of 235 °C and more than pressure of 100MPa. Ultra-deep well drilling fluid faces many serious challenges. Severe engineering problems would arise if the drilling fluid is not treated properly and even the success of the well is determined by the drilling fluid. The difficulties including complex formation, long barefoot borehole, and ultra-high temperature were confronted. The stratums of φ215.9mm hole included section KongDian 1 and section KongDian 2, in which the clay minerals in upper shale stratum consist of mainly mixed layer of inordinate illite and montmorillonite. Therefore, the troublesome conditions could probably occur during drilling. The open-hole interval was as long as about 3000m, and pressure indices of formations varied enormously. In upper stratum, after high pressure brine formation had been drilled at 4598m, the density of drilling fluid increased to 1.83g/cm3. Meanwhile, the pressure index of under-stratum was about 1.30g/cm3, so lost circulations had happened many times in high differential pressure. The high temperature of the drilling would induce complicated reaction between the clay and drilling fluid so as to slough of the clay. During drilling yield point and gel strength increased quickly with the effect of high temperature. The Poly-sulfonate plugging and anti-sloughing (5155~4598m), high density poly-sulfonate non-invasive (4598~5800m), and ultra-high temperature and super high density drilling fluid(5800~7026m) had been used in 215.9 mm interval of the well, respectively. The drilling fluid kept stationary for a long time during completion which caused drilling fluid thickening, dehydration and mud cake thickening. The solid-free anti-high temperature completion fluid was used to guarantee the success of logging and casing. It was proved in the field application of Shengke1 that the drilling fluids exhibited a series of advantages, including excellent rheology behavior, good thermal stability and low filtration rate. It was easy to treat, formulate and maintain, and could deal with the salt and brine contamination. It had been stable under 235°C of the BHT in Shengke1, the highest temperature encountered in China at that time, and guaranteed the well to be completed successfully.
Influence of Temperature on Water and CO2 Flooding of Asphaltenic Chalk Reservoirs: Experimental and Simulation Case Study
Authors: Hamouda A. A , Chukwudeme E. A. , Tabrizy V. Alipour 
Published: July 2010

Abstract
Injection of seawater into low permeable and high porous chalk reservoirs has received considerable interest as a method for enhanced oil recovery with a great challenge due to unfavorable wetting conditions, i.e. low water wetness in the matrix block.
The paper addresses two parts. The first part is related to flooding with water and CO2. The study revealed the efficiency of the CO2 flooding following water injection; however it is interesting to observe that the difference in the oil recovery is minimal at the start of CO2 injection after water injection. The oil recovery then showed vast increase in oil recovery with CO2 injection after the initial period.
The second part addresses the effect of the temperature on non-asphaltenic and asphaltenic oils showing the preferential water composition on enhancing asphaltenic oil recovery from matrix. The study demonstrates the effect of CO2 and the preferential water composition on recovery from the matrix, which concluded that the CO2 reversed the ranking of the water composition on oil recovery suggesting asphaltene/ionic interaction.
Improvement and Application of Bowers’ Velocity Effective-Stress Method in Pore Pressure Estimation
Authors: Ji Rongyi , Fan Honghai 
Published: July 2010

Abstract
In pore pressure estimation, Bowers’ velocity effective-stress method has always been a kind of computing model can not be ignored, use it to estimate pore pressure with high accuracy. Bowers pointed out that rock properties change or overpressure could cause velocity reversal data to diverge from the main compaction trend, and overpressure results from undercompaction or fluid expansion mechanisms. In the process of continued increase in effective stress, velocity-effective stress relations define the original compaction curves. As the effective stress decreases, a sharp decline in sonic velocity, velocity-effective stress relations define the rebound curves.
According to this theory, Bowers set up loading and unloading two pressure models, but in the study, we found a shortcoming in the Bowers’ unloading model. After Improvement, we arrived at a more reasonable theoretical model. In the application of well Moshen-1, we have verified its validity, and have achieved remarkable results.
Seismic Acquisition Techniques for Loess Area in Western China
Authors: Li Dajun , Sun Jianku , Chen Kaiming , Zhang Xiaobin 
Published: July 2010

Abstract
The obduction zone of Kunlun mountain foreland in southwest Tarim basin in China is covered with thick loess whose thickness changes from several decade meters to 500m, even up to 600m in some area, so, the S/N of seismic data acquired in this area is very low due to serious absorption and attenuation of seismic wave and develops strong secondary interference. Being extruded and compressed by Kunlun Mountains, the topography of this area changes rapidly, the subsurface structure is steep and complex, and the faults are very developed, which lead this area to be one of the most difficult areas to do seismic exploration in the world. The conventional seismic exploration techniques used previously can't meet the requirements of the oil/gas exploration any more, and in the area since 1978, after the Kekeya oilfield was discovered, there has been no breakthrough made. Since 1999, several seismic technique tackling studies on Kekeya edge have been carried out, and wide line receiving and source array with deep holes have been applied, but the effects are not good. In recent years, on the basis of the previous rounds of seismic exploration tackling results in the thick loess area, new research has been conducted, and seismic data with relatively high S/N been acquired, which can meet the requirements for geological interpretation. Moreover, aimed at this thick loess area, seismic acquisition technique series have been developed, and great breakthroughs have been obtained for seismic exploration in loess area, and the first-grade rate of the seismic data increased by about 20%, all of which made a solid foundation for seismic exploration of loess area in southwest Tarim, and these technique series have some reference values for seismic exploration in the similar areas.
The paper introduces some new technical achievements and knowledge for seismic acquisition in loess area of southwest Tarim basin, mainly including: (1) wide-line survey technique with high fold and long receiving spread is applied to increase the effective fold on the target horizons, and improve the quality of the seismic section; (2) source array technique with long pattern length and small charge size is applied to enhance the downgoing energy of the seismic wave; (3) long array receiving technique is applied to suppress the lateral interference and improve the signal sensitivity.
Estimate of Permeability of Fracture Corridors/Networks: from Data Acquisition to Reservoir Simulations
Authors: Zhang Xing , Koutsabeloulis Nick 
Published: July 2010

Abstract
An empirical flow model, based on the observed fracture networks and corridors of the deepwater clastic systems of Clare Basin, Ireland, shows that fracture enlargement at intersections increases the vertical flow through fracture corridors. In vertical fracture corridors, flow is dominantly controlled by fracture density and aperture, but this work also shows a significant influence from fracture intersection openings.
Only connected fracture networks contribute to field horizontal permeability, while both isolated and connected fractures contribute to vertical permeability. In this field, horizontal fracture flow needs a minimum fracture density about 4.5 m−1; below that critical density, no field horizontal fracture flow exists. For fracture aperture of 0.1 mm, field horizontal intrinsic fracture permeability can be estimated by an empirical equation: kIH(cm2) = 5×10−9d3.802 (m−1) for fracture density between 4.5 and 7 m−1; where fracture density is between 7 and 20 m−1, the empirical equation kIH (cm2) = 2×10−7d1.978 (m−1); where fracture density is above 20 m−1, kIH is close to field vertical intrinsic fracture permeability (kIV) because more and more fractures are connected to form flow channels.
The workflow introduced here estimates field scale-fracture permeability using discrete fracture networks (DFNs) for reservoir simulations from seismic and well logs. We estimated the vertical permeability of both simulated fracture networks and natural fracture networks from the sediment rock exposures in the English Lake District, estimating both vertical and horizontal intrinsic fracture permeabilties based on fracture density (d).
Seismic Prediction of Carbonate Reef or Oolitic Reservoirs in Central Sichuan Basin
Authors: Deng Ying , Li Yalin , Li Zhirong , Zhang Yanchong , Jiang Wei 
Published: July 2010

Abstract
According to previous geological achievements, the development of the reef or oolitic reservoir is closely related to sedimentary facies. The reef or oolitic reservoir belongs to hidden lithologic trap, and the sedimentary evolution process and palaeogeomorphology settings of open sea platform-ocean trough sedimentary facies belt formed in the Late Permian in Sichuan basin are very complicated. As the platform continuously increased, ocean trough gradually disappeared in Feixianguan Period. Furthermore the physical properties of the reef or oolitic reservoirs have features of lithologic traps, such as strong heterogeneity and complex gas-water relationships which make it very difficult for seismic prediction. In recent years, we developed sedimentary facies prediction technique as well as seismic prediction technique series of carbonate reef or oolitic reservoir by tracking on seismic prediction techniques of carbonate reef or oolitic reservoir based on seismic facies.
First, we made fine horizon correlation and sequence stratigraphy analysis, then simulated the multicycle sedimentary evolution process from the Feixianguan to Changxing period. After that, we applied the following techniques: forward modeling, layer flattening, ancient landscape restoration and seismic facies pattern. Finally we established different sedimentary facies belts and made seismic prediction. According to the analysis on the reservoir features of logging data, we established reservoir identification pattern which expressed low gamma and low acoustic impedance. Then we adopted facies-controlled inversion technology, carried out reservoir prediction in the favorable facies belts of reef and oolitic reservoir; finally made gas and water detection with such techniques as waveform decomposition and frequency alias attenuation and so on.
The carbonate reef or oolitic reservoir prediction techniques have been widely applied and good drilling effects have been obtained. In central Sichuan, 40 exploratory wells have been deployed after using these techniques prediction results. Presently, 22 wells have been completed and among them 20 wells have drilled reef or oolitic reservoir. By using these techniques, the distribution of reef or oolitic reservoir was ascertained further in the two banks of Kaijiang-Liangping trough, and the west bank of western Hubei trough. And the hydrocarbon exploration fields in Sichuan Basin were widened.
EOR of Superheated Steam Injection in Shallow Heavy Oil Reservoir: A Case Study
Authors: Wu Yongbin , Ma Desheng , Liu Shangqi , Wang Hongzhuang , Zhao Xin 
Published: July 2010

Abstract
This paper demonstrates a case study of the superheated steam injection methodology studied and utilized in the North Кенкияк oil field. The methodology is studied from its mechanisms of enhanced oil recovery by approaches of reservoir engineering, in-house experiment and numerical simulation, which indicate that by injecting the superheated steam, the advantages of rock wettability conversion, more heat enthalpy, larger specific volume and latent heat of vaporization of superheated steam would result in the better production and economic performance. Pilot test wells reinforced the study and the field application is planed and optimized.
Exact Non-Newtonian Flow Analysis of Yield Stress Fluids in Highly Eccentric Borehole Annuli with Pipe or Casing Translation and Rotation
Authors: Chin Wilson , Zhuang Xiaoying 
Published: July 2010

Abstract
Non-Newtonian flows in highly eccentric annuli with cuttings beds, washouts and fractures, encountered in cementing and managed pressure (and underbalanced) drilling, are solved without crude slot flow and hydraulic radius approximations. The nonlinear partial differential equations, written to customized, boundary-conforming, curvilinear coordinate grid systems providing high physical resolution in tight spaces, are solved exactly with no-slip conditions, and detailed velocity, apparent viscosity, shear rate and viscous stress fields are computed for pressure drop, hole cleaning and other applications. For fluids with yield stress, well known uncertainties related to plug zone size and shape are fully resolved using generalized Bingham plastic and Herschel-Bulkley relations applicable across transition boundaries (determined iteratively as part of the solution) reaching into and across the plug. Two-dimensional, single-phase, steady flow simulations, solved rapidly using finite difference methods, provide detailed numbers and color displays for all physical quantities within seconds, with excellent numerical stability for all fluid types with and without yield stress. Formulations for steady-state casing or drillpipe longitudinal translation and rotation are described, and extensions to model transient incompressible effects associated with starting, stopping and periodic movement, important in evaluating cement-mud displacement efficiency, axial-helical cuttings transport, swab-surge, and jarring remedies for freeing stuck pipe, are discussed. Practical problems are presented and the advantages over existing models are described. These methods extend those in the author's books Borehole Flow Modeling in Horizontal, Deviated and Vertical Wells (Gulf Publishing, 1991) and Computational Rheology for Pipeline and Annular Flow (Elsevier, 2001).
The Effect of Casing Eccentricity on the Casing Stability Analysis of a Wellbore Drilled in Gas Hydrate Bearing Sediments
Authors: Salehabadi Manoochehr , Jin Min , Yang Jinhai , Ahmed Rehan , Tohidi Bahman 
Published: July 2010

Abstract
Conductor pipe is a surface casing installed in the first few hundred meters in deepwater drilling operations (tens of meters in onshore operations) and it is used to prevent borehole collapse (and protect unconsolidated surface formations against washing out by drilling mud). Gas hydrate bearing sediments found typically near to the seafloor in deepwater environments are very soft and unconsolidated formations. Hole enlargement and wash-out are problems during the drilling these types of formation. As a result, the casing eccentricity is inevitable in the case of borehole washout (in particular if there are not enough centralizers placed on the casing).
The circulation of hot drilling mud during subsequent drilling operations or production of hot hydrocarbon after completion of the wellbore will dissociate gas hydrates in the formation behind the casing. Water and gas resulted from gas hydrate dissociation cannot flow away if the permeability of the formation is very low causing high pore pressure to trap behind the casing. The trapped pore pressure in combination with the casing eccentricity may endanger the stability of the casing depending on the magnitude of trapped pore pressure, degree of casing eccentricity and the mechanical strength of the casing. As a result, the development and drilling operations in deepwater environments can be challenging if there are gas hydrate bearing sediments.
In this communication, a numerical model is developed using a finite-element code in order to analysis the casing stability of the wellbores drilled in gas hydrate bearing sediments. The model is used to analysis the casing stability of the wellbore under uniform and non-uniform loadings. The non-uniform loading is introduced in the model by considering the presence of eccentric casing together with the pore pressure increase due to gas hydrate dissociation.
The results of the model show that the casing eccentricity is an important issue in the casing stability analysis of the wellbores drilled in gas hydrate bearing sediments in deepwater environments. The higher degree of casing eccentricity, the higher the magnitude of stress generated in the casing during subsequent operations, which may lead to casing collapse
A Fast and Efficiency Numerical Simulation Method for Supersonic Gas Processing
Authors: Dengyu Jiang , Eri Qitai , Wang Changliang , Liu Huoxing , Yuan Yao 
Published: July 2010

Abstract
Supersonic swirling separation technology is an innovative gas conditioning technology to separate heavy hydrocarbon and water vapor from the natural gas. The Laval nozzle, where the condensation occurs, is used to generate supersonic flow and achieved a high degree of supersaturation in natural gas dehydration unit. Therefore, the nozzle shape has a strong impact on the non-equilibrium phase transition and plays a decisive role to the distribution of the nucleation and the growth rate. To optimize the structure of the Laval nozzle and achieve higher separation efficiency, numerical simulation plays an important role in accelerating development cycles and cutting down the cost of experiment.
In this paper, to avert the complexity of using the multiphase models and real gas model, a quick and efficiency method is validated and used to determine the location of the nucleation zone and the droplet growth zone.
The corrected Internally Consistent Classical Theory (ICCT) model and Gyarmathy model (gya82) were employed to the numerical simulation of a condensing Laval nozzle flow by coupling the N-S equation and condensate mass equation at different nozzle pressure ratios (NPR) and initial supersaturations. The results show that, in a supersonic expansion Laval nozzle flow, high cooling rate results in a high value of supersaturation and nucleation rate. When condensation occurs, the flow is affected by the latent heat released and the total temperature is increased. This method can accurately predict the distribution of the condensing flow parameters, find an optimized flow state to obtain larger droplet, and assure the latent heat released is moderate to maintain a steady flow. Finally, this method is applied to the numerical simulation of a full-scale supersonic swirling separator flow field under different work conditions.
Comparison of the Penetration Rate Models Using Field Data for One of the Gas Fields in Persian Gulf Area
Authors: Rahimzadeh H. , Mostofi M. , Hashemi A. , Salahshoor K. 
Published: July 2010

Abstract
Estimation of the drilling rate of penetration (ROP) has always been a challenge for drilling engineers, since it is the key parameter in drilling optimization. There are many parameters which have significant influence on ROP. Relating penetration rate to these parameters result in defining a model for penetration rate. Hence, several rate of penetration models have been proposed. Among these models, the most well-known ones are Bourgoyne and Young, and Warren's models. In each of these models different parameters have been used to estimate the ROP.
The application of different parameters and their corresponding weights causes the models to predict the ROP with different accuracies. In addition, usage of different assumptions in developing the models results in quiet different areas of application for the two mentioned models. Hence, studying the models' applications and comparison of them would lead to the more successful model recognition.
In this paper, ROP equations are obtained for some depth intervals based on the two mentioned models. For this purpose, drilling data from two wells in one of the Iranian gas fields in Persian Gulf area is used. Based on the resulted equations, the two models are compared and the more suitable equation for future drillings in the same field is proposed.
The result of this study would leads to a large amount of saving in time and money in drilling the new wells. Although one of the models may excel the other one in some cases, it is not true in general. Therefore, some useful recommendations on the usage and application areas of each model will be worked out which leads to low cost drilling, real-time monitoring and optimization, and ROP enhancement.
Experimental Study of Hydraulic Fracturing Caused by Polymer Injection in Unconsolidated Heavy Oil Reservoirs
Authors: Zhou Jian , Dong Yufei , de Pater C. J. , Zitha Pacelli L. 
Published: July 2010

Abstract
Polymer flooding provides a better mobility ratio than water flooding, for a better sweep especially in viscous oil reservoirs that have been under water flood. During polymer injection, larger fractures may be induced compared with water injection. The geometry and propagation behaviours of fractures caused by the injection of viscous fluids in sands under bi-axial stress that simulated unconsolidated formation were studied. The results showed that the geometry of fractures induced by viscous fluids in an unconsolidated formation is a dominantly planar fracture, although it is very tortuous. In view of isotropic stress in the horizontal plane, multiple fractures were induced in several directions. Similar fractures were observed when the injection fluid viscosity was varied by a factor of 3, while keeping the mobility ratio constant. The tests confirm that the injection pressure should exceed the minimum stress by a factor of 2.5 to induce fracture propagation. Below this pressure only matrix flow occurred, although the permeability was enhanced by the injection.