bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fracture Geometry Inversion Technique in Low Permeability Reservoir for Horizontal Well
Authors: Wenjun Wang , He Liu , ying Yu , Bing Wang 
Published: July 2010

Abstract
The validity and pertinence of hydraulic fracture performance of horizontal well is important issues. How to combine multi disciplines such as reservoir engineering and logging and so on to implement the research project is a critical concern. Also, how to optimize the orientation and magnitude of parameters in analyzing fracture treatments is one of key steps to produce low permeability reservoirs in fields. Based on practical examples, fracture shape inversion technique of horizontal well fracturing was carried out by analyzing logging data, monitoring fracture data, and running 3-D fracture numerical simulation computer tools. Fracture spreading characteristics were analyzed and fracturing effect was verified. This fracture inversion technique is able to optimize fracturing design, evaluate and establish feasible development program for the region.
Drilling Technology of HTHP Ultradeep Well and the Crucial Technique Application
Authors: Zhankui Liu 
Published: July 2010

Abstract
There are many difficulties in HTHP ultradeep well drilling, drilling technology of HTHP ultradeep well is still the focal point of drilling researching and developing at present. This paper introduce drilling technology of HTHP ultradeep well moshen-1 well. Specially, this paper give information of the crucial technique application in Xinjiang Karamay Oilfield. Moshen-1 well is an important exploration well of CNPC, the designed well depth was 7380m, the actually completed well depth 7500m. Drilling engineering encountered huge challenges for instance high bottom hole temperature and high formation pressure coefficient, no reference data below depth 5300m. By optimizing drilling design, the construction of every drilling section was successfully finished. By optimizing BHA and using Power-V vertical drilling system, combine a large-sized PDM with PDC bit, using turbodrilling, all helped controlling wellbore quality effectively. By optimizing bit design and PDC bit selection increased drilling bit footage. Specially, 35MPa high pressure jet drilling technique had effectively increased bit hydraulic horsepower and improved the drilling ROP, reduced drilling cycle, achieved success contrast with neighboring well. The success of Moshen-1 well drilling and the application of high pressure jet drilling technique provide valuable experience for other ultradeep wells drilling and for other wells ROP enhancement.
Mesoscopic Simulation of Rheology of Polymer Solution
Authors: Li Xiaobo , Song Jie , Yuan Jiangru , Dai Yang 
Published: July 2010

Abstract
The need for high performance polymers used in chemical EOR is increasing in some oil fields, especially in China. It is a challenging issue to simulation the flow of polymer solution through pores. What make the complexity of this problem are the multiple physical phenomenons that the transformations of macromolecule interact with the macroscopic flow. Both molecular and hydrodynamic effects are of important at this scale, but not all of which can be resolved by the traditional continuum-based approaches that involves solution of the Navier-Stokes equations with a phenomenological constitutive equation. Microscopic molecular dynamics, on the other hand, requires excessive calculation time before macroscopic effects become visible, and therefore dissipative particle dynamics (DPD) is used to simulate the rheological properties of polymer solution in our work. As a particle-based mesoscopic method, the DPD method is appropriate to study complex fluids including polymer or surfactant [1]. In this study, the polymer molecule was represented with a chain of beads connected with finite extensible nonlinear elastic (FENE) springs that led to viscoelastic flow, and the periodic Poiseuille flow method proposed by Backer et al [2] was applied to measure the viscosity of simulation system. The rheological properties of linear, branch- and star- polymers solution were simulated, and some factors including molecular weight, molecular topology and concentration were evaluated quantitatively. Besides that, the radius of gyration of polymers was recorded in simulations. In our opinion, the numerical instabilities of many conventional methods can be avoided in this approach, and the simulation results gave a clear physical insight into the flow of polymer solution.
New Cementing Technologies Successfully Solved the Problems in Shallow Gas, Low Temperature and Easy Leakage Formations
Authors: zhen Nie , Dong benjing , Xia boru , Zheng xiu shan , Xie chengbin 
Published: July 2010

Abstract
The buried depths of reservoirs in North Buzachi oilfield range between 400~500m, but Its geologic structure is very complex due to the existence of shallow gas and aqueous layer within 20~160m and a HP gas layer at 300m(1.30–1.50 g/cm3). In addition, the reservoir is easy to leak for its high permeability and low fracture gradient (1.6g/cm3), and the ground temperature is −40□ in winter. All these factors bring great challenges for the cementing jobs here and often result in poor cementing quality such as shallow water & gas channeling from wellheads and serious leakage in reservoirs. 72 out of the 97 wells cemented during 1974~2000 were abandoned due to poor cementing jobs. Gas and water channeling were found from 15 wellheads that were cemented from 2003 to 2004. This paper focuses on how we develop a new cementing technology to improve the cementing quality in this oilfield. Based on the High Packing Theory, we developed the High Performance Low Temperature No-waiting & Low Density Cementing ™ technology(NLDC) whose slurry density can as low as 1.20g/cm3, which includes high performance cementing additives, superfine active mineral materials, Super-low temperature accelerator, and Anti-migration additive, etc. This technology are characterized by good anti-channeling & Anti-leakage & early strength development ability under the temperature 20~30□. Up to now, more than 300 wells have been cemented successfully with this technology, 97% of which are with excellent bonding quality. Those problems which have puzzled the North Buzachi for long have been radically solved, such as bad isolation, annular migration, shallow gas and water blowing off from wellheads and leakage during cementing. This NLDC cementing technology has been widely applied in North Buzachi oilfield for 5 years and also a good solution to shallow gas & water cementing and low pressure-easy-leakage formation cementing.
The Study of Fracture in Volcanic Reservoir
Authors: Fang Jie , Jia Chengzao , Ran Qiquan , Hui Gang , Zhou Xinmao 
Published: July 2010

Abstract
The 1'st members of Yingcheng formation, lower Cretaceous in Xingcheng development area, Songliao Basin mainly have rhyolite gas reservoirs. The 1'st member of Yingcheng is belong to the low-porosity and low-permeable reservoir, the reservoir space are mainly fracture-pore. By the means of field out crops observation, core description, thin section analysis, well logging identification and the seismic forecasting, the fractures of 1'st member of Yingcheng volcanic reservoir was analyzed in three aspects: the genetic, the attitude and the width. The dominate fracture type of 1'st member of Yingcheng are the tectonic related fractures(78.5%), then the diagenetic related fractures(17.0%), corroded fractures(4.2%) are the last. The high angle fractures and the vertical fractures are most common in tectonic related fractures; the oblique fractures are the following. The dominate type of diagenetic related fractures are level fractures, followed by high angle and oblique fractures. The fractures in the reservoir were mainly wide fractures (width&gt;1mm) and narrow fractures (0.1mm&lt;width&lt;1mm), the fractures of middle width are the minority. The distributions of the fractures were mainly controlled both by the regional stress field and the activity of the faults, the fractures are displayed by belts in coincident with the strike of the main faults.
Scour and Deposit Analysis of Artificial Island in Nearshore Oilfield Development
Authors: Wang Shipeng , Qin Yanlong , Yao Zhiguang 
Published: July 2010

Abstract
In nearshore oilfield development, artificial island is the better method because of the economic and technical convenience. But compared with the traditional way of reclaiming land from beaches, the construction of artificial island should be given with more attention to the ocean hydrological and dynamic changes, the mutual implication between engineering zone and marine environment. It will spend more time and money to deal with the sedimentation scour and deposition around the island. So the island construction should consider the sedimentation transportation and environmental safety.
In this paper, a preliminary analysis on marine dynamic variation was presented based on the analysis of available data. Numerical model of tidal currents with wave effects was established in order to analyze the influence of nearshore oilfield artificial island on the environment. Sedimentation transportation under the coactions of wave and tide was investigated in order to analysis the stability of artificial island and marine dynamic geomorphology.
By taking a practical example of a typical artificial island, the effects of the construction of artificial island on environment and sand transportation were investigated. The artificial island should build with appropriate plane layout and make full advantages of the existing topographic and hydrodynamic condition. The construction of artificial island must minimize impact on environmental condition to reduce sedimentation scour and deposition and enhance the safety of oilfield.
A Downhole Blowout Preventer with the Equipment of Pressure Measurement
Authors: Gao Benwen , Chen Ruoming , Song Zhaohui , Li Xiaojun , Mu Zongjie 
Published: July 2010

Abstract
With the rapid development of Under-balanced Drilling (UBD) technologies, more and more people come to realize that the UBD is one of the most effective drilling technologies in reservoir exploration. However, the conventional Underbalanced Drilling Technology has its own faultiness. Take tripping pipe and liner for instance, we have to operate the well killed for well-control safety. The kill weight mud (KWM) will increase Bottom Hole Pressure (BHP) and make the down hole overbalanced. This will decline the effectiveness of reservoir protection in UBD technology.
The present paper aims to provide a new type drilling tool, named Downhole Blowout Preventer (DBOP), developed by Xinjiang Drilling Technology Research Institute of Western Drilling Engineering Corporation of CNPC, which could achieve a wellbore full-procedure underbalanced effectively. There’re some advantages in DBOP, such as hydraulic control, reliable gas/ liquid sealing property, pressure real-time transmission of valve, etc. Moreover, the DBOP can save drilling cost enormously and guarantee the behavior of barren bore safely.
The DBOP tripping in wellbore as one of intermediate casing, is in open condition during the running casing procedure. When tripping occurs, the DBOP, which has a valve, will isolate the wellbore into two sections (upside section and underside section) by closing its valve. For the sake of well isolation, the DBOP has perfect sealing property to isolation fluids which may include drilling mud and formation fluids. During the procedure of coming out of the hole, when the bit arrives at the upside section, the DBOP will close its valve timely; while, during the procedure of going in the hole, the DBOP's valve will be unclosed when the bit closes to the DBOP.
Because of DBOP's coordinating with Rotating Blowout Preventer (RBOP), the full-procedure underbalanced drilling achieves efficiently.
The Downhole Blowout Preventer (DBOP) has been used in some oilfields successfully, such as Xinjiang Oilfield, Huabei Oilfield, Sichuan Oilfield, etc. The effectiveness of DBOP has been proven to be efficient and successful.
Genesis and Prediction for Overpressure Carbonate Reservoir-Case study of Kenkiyak Sub-salt carbonate reservoir in Kazakhstan
Authors: Yefei Chen , Lun Zhao , Zifei Fan , Yunjuan Li 
Published: July 2010

Abstract
The genesis of the overpressure carbonate reservoir is not controlled only by lithofacies, karstification and tectonic movement, but also by overpressure. The hydraulic fractures formed under overpressure and its connection and expansion to early solution vugs and structural fractures are the key factors to the high productive zones.
Kenkiyak Pre-salt Oilfield is the carbonate reservoir with a burial depth of more than 4300 meters. The matrix permeability is only 0.98md. It was considered as a very low permeability porous-type reservoir and was defined as the oilfield without economic benefit. According to this study, under the overpressure condition, that the pressure of the porous liquid is up to 80Mpa, the carbonate reservoir cracks to form natural hydraulic fractures. Reticulate hydraulic fractures combined with structural fractures and solution vugs make very good spatial configuration, and then form the pore-fractural dual- media reservoir. The high productive reservoirs form under the condition of the favorable sedimentary facies, karstification cells and structural locations.
Because of the overlying salt-dome with 120–3800 meters in thickness, the imaging of the seismic data is very poor and it is very difficult to predict reservoirs. The seismic processing techniques such as kirehhoff prestack time migration, diving wave tomo and CIP grid tomography are applied to improve the migration image and signal-noise ratio. Based on analysis of the control factors to the carbonate reservoir, using the data of the drilling, logging and dynamic test data, the lithofacies, palaeokarst and the fracture system are predicted and the distribution of the high productive zone is successfully predicted by applying the techniques of the seismic muti-attribute clustering analysis and seismic inversion. The average productivity of the new drilling wells in the predicted high productive zones is up to 300t/d, and the oil rate per day of the 2 wells is over 1000t.
New Development and Application of Underbalanced Drilling Technology in China: A Critical Review
Authors: Cheng R. C. , Wang H. G. , Ge Y. H. , Cui M. , Ma G. Z. , Fei H. M. 
Published: July 2010

AbstractMost of mature oil fields in China have been developed for decades of years, the majority of hydrocarbons being exploited today are found in pressure depleted formations or complex and lower quality reservoirs. Underbalanced drilling (UBD) is identified as an effective way to address problems associated with conventional overbalanced drilling, but its development and application in China is still on the preliminary stage. To cost-effectively serve for the complex exploratory situation, CNPC (China National Petroleum Corp.) initiated a large-scale UBD campaign from 2007 as a major change of its economic growth pattern.This paper is a critical summarization of the ongoing campaign, with its purpose to explain where we are and what to do next. It highlights the new developments in techniques and auxiliary equipments in: 1) the whole process UBD, in which self-made equipments like the liquefied gelling valve and casing valve were particularly introduced; 2) underbalanced horizontal drilling, which plays a more important role in developing fractured reservoirs; 3) gas drilling, which gains further enhancement in air hammer, circulated medium diversion, water production prediction and reduction, and significantly improves drilling speed in deep formations; 4) managed pressure drilling (MPD) based on UBD equipments, which more precisely controls the annular pressure profile and effectively eliminates lost circulation in highly fractured zones; 5) bottom hole pressure measurement while drilling, which provides necessary information for the design of equivalent circulating density (ECD) as well as the control of bottom hole negative pressure in UBD. Case histories show that the UBD campaign not only improves drilling speed, reduces non-productive time (NPT), protects reservoir, but also enables comprehensive characterization of the reservoir while drilling, making smaller-reserves targets viable and previous low quality formations producible. In addition, the development trend of UBD in CNPC was discussed, and recommendations were proposed.
Detailed Hydraulic Simulation of MPD Operation in Narrow Pressure Windows
Authors: Cui Longlian , Wang Haige , Ge Yuhua 
Published: July 2010

Abstract
Hydraulic simulation is an integral part of any Managed Pressure Drilling (MPD) operation. Engineers rely on hydraulic calculation throughout an MPD project. A very detailed wellbore hydraulic analysis will not only foretell the success of various MPD methods but may also guide the drill engineer in real-time while contenting with difficult hydrodynamcis scenarios. Most MPD operations are conducted in narrow pressure windows formation, which require the pressure in "precise control". However, there are many parameters that play a part in the managing of wellbore pressure during circulation. Bottom hole pressure are impacted by fluid density and rheologic properties, injection rates, temperatures in annular and pipe, casing and drilling string configuration. The effects of these parameters on the bottomhole pressure are different, but interact with one another. A good understanding of the effects of these parameters on bottomhole pressure is essential in the hydraulic simulation.
In the paper, detailed hydraulic analyses of MPD operation in narrow pressure windows are presented. The detailed inform collecting is the first step for hydraulic simulation. According the drilling fluid used in the MPD operation, the rheology models of drilling fluid were compared and determined. The Roberston-Stiff model was employed in this paper. Based on experiments and theoretical analysis, the effects of temperature and pressure on ESD and shear stress of drilling fluid were considered. Some often overlooked parameters such as tool joint parameters, pump feed efficiency etc., were also considered Integrated into account the above factors and other conventional factors such as hole geometry, drilling string configuration, etc., the hydraulic simulations of MPD were conducted. The simulation results were compared with on-site real time PWD data. The hydraulic simulation results are in good agreement with on-site real time PWD data.
New Development on Expandable Casing Hole Liner and Expandable Open Hole Liner
Authors: Gao Xiangqian , Li Yiliang , Zhang Lixin , Han Weiye 
Published: July 2010

Abstract
High-temperature Expandable casing hole liner (ECL) was unsuccessful. The rubber element can not sustain the temperature higher than 160 °C, and steel bevel elements can not meet the requirements for sealing and hanging. In our research copper bands were inlayed on the steel pipe; an optimal manufacture process made the welding of copper had little effect on the mechanical behaviors for both steel and copper, which insured the lower expansion pressure and better sealing. These were tested by the expansion experiments and the following cycled temperature loading and hydrostatic test, the sealing elements can sustain the external pressure 20MPa. We designed an ECL for casing remediation in horizontal well, in which the expansion cone moves downwards. This design avoided the gravity and fraction of oil tube, which leads to the lower expansion pressure. Expandable open-hole liner (EOL) was a well completion plan for sidetracking well for its bigger inner diameter (I.D.), but decentralized EOL led to the cementing failure. In our plan the reamer was not used after the sidetracking, the expansion cone expanded the tubular up to the open hole together with swelling rubber elements for zonal isolation. The most important aspect that affects the intensity of Expandable Tubular was the thread. We modified the structure of thread: increasing the wall thickness at both ends before threads are done, upsetting or welding thicker pipe at the ends are both applicable.
Implement Fine Redevelopment to Keep Old Oilfield Sustainable Development —A Case from the T2k1 Reservoir of the Eastern District No.1 Block of Karamay Oilfield
Authors: Yang Shengzhen , Xiao Chunlin , Lin Jun , Yuan Shuwu , Wu Rangbin 
Published: July 2010

Abstract
The redevelopment of the T2k1 reservoir of the Eastern district NO. 1 Block of Karamay Oilfield is a pilot tracey of II conglomerate reservoir of Karamay Oilfield. Through a variety of technologies of detailed descriptions of reservoir, recalculating the amount of resources and the dynamic flow lines as well as evaluation of watered out zone etc, optimize simulation model, refine and quantify the remaining oil and recognize the potential reservoir comprehensively. Based on the evaluation of well pattern in history, combined with reservoir engineering, numerical simulation methods, optimize wellnetwork and well-spacing and rebuild well-network structure, implementing the secondary development. After adjusting reservoir development plan, carry out research of rational exploitation limit, fine water injection and reasonable regulation of pressure field, achieving stable production of secondary development. Through the fine secondary development succeeded in making an already developed 50 years and nearly abandoned oil reservoir once again rejuvenated. Furthermore, yearly oil production of the old oilfield rose from 1.5 × 104t to 7.1 × 104t, the ratio of adjustment wells obtain the design rate is up to 94%, the proportion of achieving production capacity is 107%. Successful explore and form a series of technologies to make the production steady after redevelopment of the II conglomerate reservoir of Karamay Oilfield, which have a very important significance for old oilfields to achieve sustainable development.