bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical Simulation of Subsea Wellhead Stability for Deepwater Drilling
Authors: Guan Zhichuan , Su Kanhua , Qing Chong , Su Yinao 
Published: July 2010

Abstract
Subsea wellhead bearings complex stress because it joint with the marine riser and casing string. According to mechanical analysis of subsea wellhead for deepwater drilling, a comprehensive stability of subsea wellhead analysis method was established. The marine environmental loading, drilling vessel drifting, riser mechanical behavior, nonlinear behavior between casing string and formation were considered. A numerical method was adopted to solve this model. Example analysis illustrates, in order to improve the condition of riser, riser top tension is ordinarily increased. The lateral displacement and bending moment of wellhead nearly linear enlarged with the mean drifting offset. The greater TTR may cause wellhead instability because of the wellhead has a limited bearing moment capacity, and then need to disconnect the LMRP and BOP connection promptly. The affection of lateral load is focus on the upper string section, more depth of casing string is almost no affecting on its lateral bearing capacity. With drilling vessel offset or TTR enlargement, the lateral displacement, bending moment, shearing force and the soil reaction along string increased obviously, and acting depth deepened gradually. The measures such as enhance the conductor bending strength, control scour depth on seabed, get geological data sampling of shallow formation can strengthen the stability performance of wellhead.
Hydraulic Pulsed Cavitating Jet Assisted Deep Drilling: An Approach to Improve Rate of Penetration
Authors: Li Gensheng , Shi Huaizhong , Niu Jilei , Huang Zhongwei , Tian Shouceng , Song Xianzhi 
Published: July 2010

Abstract
Hydraulic pulsed cavitating jet drilling is a new combined drilling technology. In this technology the hydraulic pulsed cavitating jet generator is installed upon the bit in the drilling process. Based on modulating pulsed jet and cavitating jet, a new drilling tool is designed which couples advantages of both pulsed jet and cavitating jet. When drilling fluid flows through the tool, fluid is modulated to pulse and cavitation. Thus, pulsed cavitating jet is formed at the outlet of the bit nozzle. Because of jet pulsation, cavitating erosion and local negative pressure effect, bottom cuttings cleaning efficiency is enhanced and the rate of penetration (ROP) is improved. This paper studied the mechanisms of improving the ROP and cuttings cleaning efficiency in hydraulic pulsed cavitating jet drilling. Hydraulic pulsed cavitating jet drilling technology has been applied in 8 oil fields in China, such as Tarim oil field, Xinjiang oil field, etc. The tests in more than 40 wells showed good applicability of the tool to bit types, formations, drilling fluid densities, etc. Hydraulic pulsed cavitating jet can mate with helicoid hydraulic motor and Power V system drilling technology, this technology also can be used in underbalance drilling. The test well depth is 1274 ~ 6162 m. As the result, ROP was improved by 10. 1 to 104. 4 percent and the maximum operation time is about 260 hours in wellbore. Pulsed and cavitating jet coupling can afford an effective approach to improve ROP in deep and ultra-deep well.
Flow Regimes and Transition Characters of the High Viscosity Oil-water Two Phase Flow
Authors: Wang Wei , Gong Jing 
Published: July 2010

Abstract
With the fast development of the offshore oilfield in china, field engineers are now facing with a new challenge, which is the flow assurance of crude oil-water two phases flow in the submarine pipeline. Since the existence of natural surfactants in the crude oil, as resin, asphaltene and etc, crude oil and water two phases tend to form stable water-in-oil (w/o) emulsion and therefore greatly influence their flowing characteristics, as flow patterns and transition characters and especially the pressure drop character.
These have shown obvious differences from the flow of mineral oil-water two phases, which are commonly and widely used for indoor experiments, even when the density and viscosity properties of the mineral oil and crude oil phase are approximately the same. For the guidance of the design and operation of the offshore crude oil-water pipeline, high viscosity mineral oil / crude oil-water two phase flow through horizontal pipe were conducted in a steel laboratory pipe loop (1 inch inner diameter, 52m length). Major similarities and differences are compared between their flow patterns and transition characters.
How Variable Fluid PVT Model Affects the Performance of an Integrated Production System
Authors: Nnochiri Michael , Lawal Kazeem A. 
Published: July 2010

Abstract
Contrary to general assumption, the composition and saturation point of a petroleum fluid system rarely remain constant throughout its production lifetime or transportation path. Consequently, for reliable forecasts of long-term system performance, the initial isothermal model describing the pressure-dependency of fluid properties may no longer be valid. This may warrant pressure-volume-temperature (PVT) model update(s). Ideally, such updates should necessitate regular re-sampling and re-characterisation of reservoir fluid (mixture). However, this may not be pragmatic because of frequency of changes, both between sampling periods and sampling points, in an integrated production system (IPS).
For an IPS, this paper investigates "possible" reference conditions for approximating these PVT variations without recourse to fluid re-sampling and re-characterisation, yet achieving reasonable results. Initial, bubble-point and abandonment conditions, as well as intervals between them, are studied as possible candidates. As a measure of relative performance of these approximate models, recoverable volumes (discounted and undiscounted) of oil, gas and water are compared against those whose hydraulic models are based on the full suite of initial PVT deck. A coupled subsurface-surface system of undersaturated black oil was studied.
By retaining the initial PVT model throughout the network, predicted oil recovery could be optimistic, up to 38% in this example. However, where a water injection scheme is implemented, corresponding volume of recoverable water could be significantly underestimated, as much as 40% in this example.
In conclusion, the effects of PVT variations might be significant, and for realistic simulation of life-cycle performances, it is recommended that such anticipated variations be incorporated, consistently and efficiently, for the reservoir, wellbore and other subsystems of an IPS. As a future work, the investigation should be extended to the more dynamic volatile oil and gas condensate systems.
Uniform Steam Injection Technology Used in Thermal Horizontal Wells
Authors: Pingyuan Gai , Yongxin Du , Guocheng Lu , Xiaonan Li , Zhiyong Luan , Shulan Li 
Published: July 2010

Abstract
Horizontal well technology is very effective to enhance oil production rate of single well in heavy oil reservoirs because of its large oil drainage area compared with vertical wells. However, since the influence of steam injection parameters and reservoir heterogeneity, length of steam absorption section in thermal horizontal wells is only 50m~70m by using conventional steam injection pipe string. Nowadays, length of completion section in thermal horizontal wells is generally about 200m, therefore controlled reserves in 130m~150m horizontal section can't be effectively produced by using conventional steam injection technology. In order to improve recovery effect of thermal horizontal wells, adaptive uniform steam injection technology is developed in Shengli oilfield. Based on studying and designing adaptive uniform flow regulator, steam injection parameters, number and arrangement of adaptive uniform flow regulators are optimized according to steam equipment capacity and reservoir properties, thus realizing uniform steam absorption in long horizontal sections. Reservoirs of whole horizontal section in thermal horizontal wells can be effectively produced and producing degree of controlled reserves in horizontal wells can be increased. Not only oil recovery rate of thermal horizontal wells is enhanced, but also oil recovery ratio.
The Use of Monte Carlo Simulation for Uncertainty Estimation in Gamma Densitometry Measurements
Authors: Arubi I. M. , Yeung H. 
Published: July 2010

Abstract
Measurement uncertainty is increasingly seen as essential in quality assurance for industry. The uncertainty associated with a value of a physical quantity provides a quantitative measure of the reliability and trustworthiness of that value. The ISO Guide to the Expression of Uncertainty in Measurement (GUM), which provides international agreed recommendations for the evaluation of uncertainty, recommends an approach based on the propagation of distribution using Monte Carlo Simulation (MCS). Uncertainty in multiphase flow measurement results from the uncertainty in the fluid density, phase volume fraction and velocity measurements.
In this work, the application of MCS as flow measurement uncertainty estimation method for gamma densitometry in multiphase flow is presented. A response database was obtained by pulling up Polyvinyl Chloride (PVC) ‘blobs’ in a static column of water/oil. Phase volume fractions and velocities measurement were obtained from the energy attenuation data of a caesium-137 radioisotope-based densitometer. MCS is then used to estimate the uncertainties in these measurements.
We present preliminary results and demonstrates the simplicity and reliability of this approach to uncertainty assessment. We opined that this method is suited for radiation-based metering technique because of its reliance on randomness, as such it does capture the natural stochastic process inherent in the interaction of gamma rays and multiphase flow.
Successful Application of the New Double-effect Protector in Deep Well Drilling
Authors: Zhu Xiaohua , Liu Shaohu , Shi Changshuai , Tong Hua , Nie Rongguo 
Published: July 2010

Abstract
This paper discusses a new double-effect protector (DEP). The serious wear of casing and drill pipe brings huge economic losses in drilling. On the basis of the traditional technology, a new DEP is designed, to reduce the wear of casing and drill pipe. The DEP's volume, which can be worn, increases 14% than the traditional protector's. As design and optimization by CAE software, the maximum stress, which is caused by the contacting collision&friction, is greatly lowered. As design and optimization by using CFD software, the fluid pressure loss of the DEP's annulus space, is decreased 17.5% than the traditional protector's. A new composite has been synthesized firstly, and has excellent mechanical performance, for example, abrasion resistant performance at high temperature. By using the Nonlinear Drillstring System Dynamics Simulation and Torque & Drag forecasting software, the study has been completed, which is about installed number and position of DEPs, for reducing wear on casing and friction on drill string in the typical deep well, and then the scheme, that the DEP is reasonably mounted, is applied while drilling. This document describes the first application of the DEP in X301 on Southwest oilfield, Sichuan, China. From the practice, the DEP's average working life has been enhanced 200 hours. Because of the use of the DEP, the wear of casing and drill pipe is effectively reduced, the quality of wellbore is improved, and the drilling period is shortened. The DEP and matching technology can provide effective technical support for deep well drilling and post-mining.
Cyclic Preheating Test in SAGD Horizontal Wells of Liaohe Oilfield
Authors: Songliang Peng , Aiwu Yuan , Hua Jiang , Shoujun Zhang 
Published: July 2010

Abstract
In the super heavy oil reservoirs of Liaohe Oilfield, the cyclic preheating of SAGD horizontal wells can only be achieved by mechanical lifting due to the deep burial depth and low formation pressure. The cyclic preheating of SAGD horizontal wells becomes even more complicated in terms of injection and production technology due to the limitation of wellbore space, the complexity of the wellbore structure of horizontal wells and the high temperature of produced fluids, leading to great difficulty in controlling the injection and production parameters. Therefore, the test was conducted to enable the injection/production ratio to be 1: 1, meeting the requirement in the reservoir design by optimal pipestring design, optimal selection of injection and production parameters and controlling the backpressure at the wellhead. At the same time, some supporting techniques, such as a new type of dual pipe wellhead for simultaneous injection and production and high temperature lifting technique have been developed, effectively ensuring the success of the cyclic preheating test of SAGD horizontal wells. By monitoring the temperature profile in the upper horizontal well, it was observed that more than 85% of the horizontal interval has been evenly heated. The success of the test has provided valuable experiences and strong technical support for conducting cyclic preheating of SAGD horizontal wells in similar reservoirs in Liaohe Oilfield and other oilfields in China, and even in foreign countries.
Simulations of Asphaltene Deposition in Submarine Pipelines by CFD
Authors: Hongjun Zhu , Jiaqiang Jing , Qingping Li , Xichong Yu , Junwen Chen 
Published: July 2010

Abstract
The transportation of heavy or waxy crude oils presents some special design problems, which must take into account the requirements for the control of asphaltene deposition on interior surfaces of the pipeline. With the asphaltene deposition of the crude oils, the effective cross-sectional area or flow passage of the pipeline will be shrunken continuously, which influences their flow properties and threatens their safe transportation. Therefore, the influence of asphaltene deposition on their flow properties should be known well to safely design and operate the pipeline. The focus in this paper is on the asphaltene deposition rate and the influence of the asphaltene deposition on flow properties.
Simulations of heavy crude oil flow in different structural pipelines after various deposition patterns are presented using 3D CFD. The flow velocity of heavy crude oil increases with the reduction of the effective cross-sectional area of the pipe, which leads to its vibration and shorter service life. In the other hand, pressure and temperature in the shrunken effective cross-sectional area decrease with the increase of velocity, intensifying the asphaltene deposition and transportation difficulty. While flow properties vary depending on deposition patterns, flow rates and the pipe geometry. So the influence of asphaltene deposition on flow properties in different structural pipelines with various deposition patterns is diverse. The impact of deposition in bending and reducer pipelines is greater than that in straight ones. And the impact in serious deposition pipelines is greater than that in slight deposition ones. So flow properties change drastically in bending and reducer pipelines with serious asphaltene deposition, leading to rapid blockage of the pipelines. The results of this paper can provide a guide for safe design and transportation of heavy crude oil pipeline.
Design of Water-based Drilling Fluids for an Extended Reach Well with a Horizontal Displacement of 8000m Located in Liuhua Oilfield
Authors: Jienian Yan , Jiaojiao Geng , Zhiyong Li , Deli Gao , Jianhua Wang , Shengying Zhao 
Published: July 2010

AbstractDesign of drilling fluids is crucial to extended reach drilling (ERD) with the challenges including borehole stability, hole cleaning, lubricity and equivalent circulating density (ECD) management. Normally, oil-based drilling fluids would be the best choice for an extended reach well with a horizontal displacement of 8000m. However, the Liuhua Oilfield is located in the South China Sea, an environmentally sensitive area. It is necessary to develop the high performance water-based drilling fluids which offer the performance to match oil-based drilling fluids.The integrated design proposal of water-based drilling fluids for the well Liuhua 11-1-B3 ERW4 with a horizontal displacement of 8000m (26247ft) is discussed in this paper, including design criteria, the formulations and the parameters of performance of the drilling fluids in each interval of the well. The more attention is paid to the 12 1/4-in. open hole section, where a kind of high performance water-based mud (HPWBM) is prepared. The two newly developed chemical additives, an amine polymer and an aluminum complex, are added in the KCl/polymer drilling fluid which was successfully used in the extended reach wells with a horizontal displacement of 6000m in this oilfield. In addition, a membrane-forming agent is added in this mud system and an optimized combination of lubricants was used to improve the lubricity of the drilling fluid.Numerous experiments were conducted to evaluate the various properties of this novel water-based drilling fluid. The experimental results indicate that it has excellent rheological properties, very low filtration rate, good lubricity and strongly inhibitive character to shale, which are very close to the commonly used oil-based drilling fluids.The results of risk analysis show that the design proposal of this water-based drilling fluid is feasible and can meet the drilling requirements of ERD with a horizontal displacement of 8000m open hole section in this area with less pollution of the sea and without increasing more cost.
Mechanisms and Prevention of Damage for Formations with Low-porosity and Low-permeability
Authors: Jiaojiao Geng , Jienian Yan , Zhiyoong Li , Zhong He 
Published: July 2010

Abstract
The protection of target formations with low-porosity and low-permeability is an advanced research project in petroleum engineering and has important significance for the increase in reserves and production. Conventionally, the core flooding tests have been adopted for determining the mechanism of formation damage. However, the permeability is too low to be carried out the core flooding tests easily for this type of formations, furthermore, the typical core samples are hard to get in some reservoirs.
Focusing on the typical formations with low-porosity and low-permeability, the mathematical models for predicting five kinds of sensitivities of formations and the damage induced by water blocking quantitatively were established in this study on the basis of numerous experimental results, applying the theory of petrophysics and interfacial chemistry for reservoirs and the intelligent method of ANN (Artificial Neural Network).
The practical software has been developed to predict the degree of sensitivities and water blocking of formations, so as to determine the mechanisms of damage and guide the design of drilling fluids. This software is very convenient for use only by inputting the related formation parameters. It can be instead of the complicated and time-consuming laboratory tests. Extensive applications show that more than 85% of predicted results are in agreement with the measured results, indicating its satisfactory reliability.
In this study, the methods for preventing the damage caused by water blocking effectively have been discussed by virtue of selecting proper surfactants. In addition, the novel drilling fluid suitable for protecting the reservoirs with low-porosity and low-permeability are developed.
Pressure Transient Analysis with a Dual Changing Wellbore Storage Model
Authors: Suzuki Ikkou , Nomura Masahiko 
Published: July 2010

Abstract
This paper presents a new model for analysis of changing wellbore storage during pressure transient testing. The model accounts for the combination of instantaneous change of wellbore storage with wellbore phase redistribution effects. Both wellbore effects are incorporated mathematically into a new solution of diffusivity equation. Type curves for various combinations of related parameters are generated to develop an insight into pressure transient behavior. The practical utility of the new model is demonstrated through application to the actual field data.
Successful Application of the Sand Removal Technique by use of Concentric Tubing Jet Pump in Karamay Shallow Heavy Oil Horizontal Well
Authors: Jia-huai Wang , Bin Xie , Xiang-jie Luo , Hong Zheng , Xin-ming Ma 
Published: July 2010

Abstract
The punched or slotted screen pipe is used for the well completion of the shallow heavy oil horizontal well in Xinjiang oilfield. But the sand is still produced significantly in some wells Because the permeability is high, the formation pressure is low, the oil sands cementation at normal temperature is strong, it is hard for the conventional hydraulic sand washing to shatter the oil/sand bed, the sand washing fluid is lost substantially, the sand carrier fluid cannot reverse out which cannot effectively remove the sand deposition in the horizontal section. Therefore, the Jet Negative Pressure Sand Removal Technique by Concentric Tubing and assorted tools were designed and developed. The computational software of sand-washing optimization was developed. The application results in 14 wells proves that this Technique can efficiently and completely remove the sand deposition in the wellbore of heavy oil horizontal well which solves the production reduction and off production problem caused by sand deposition along the wellbore in the heavy oil horizontal wells.
Operational Geological Uncertainties and Improvement Plan for 2km Dual-lateral Horizontal Well within Tight Gas Reservoir in Changbei Tight Gas Field, Ordos Basin, West China
Authors: Xiumei Gong , Kwong-Yin Soo , Wu Su , Singh Navpreet 
Published: July 2010

Abstract
Changbei field, as one of the largest onshore sedimentary basin in China, is situated at North Shaanxi Province, Ordos basin. The main tight gas reservoir deposits in the Upper Paleozoic, Lower Permian Shanxi clastic Formation (P1S2). The combination of 2km long single and dual-lateral barefoot horizontal wells is successfully used to drill from surface location "clusters" into the lower Permian Shanxi (P1S2) Formation to maximize the gas production. Several key geological uncertainties which control the optimal landing of the 12¼" well trajectory and placement of the 8 ½" hole in the reservoir along with the delivery of the 2 km horizontal well length have been identified: 1. Top reservoir prognosis, 2. Reservoir thickness prediction and 3. Spatial distribution of unstable carbonaceous claystone bodies within and along marginal reservoir areas. And relevant improvement plans that have been put in place to mitigate the operation challenges had been analyzed.