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Nediljka Gaurina-Me?iumurec,Katarina Simon,Davorin Matanovi?,Borivoje Pa?i?
Rudarsko-Geolo?ko-Naftni Zbornik , 2006,
Abstract: Historically, most underbalanced drilling (UBD) projects were undertaken to eliminate drilling problems and cost. However, recently, the reduction of formation damage has become a main focus for underbalanced operations. This has the greatest potential in directly increasing the profit to the operating company. Potential benefits include increasing of production rate, the ultimate recovery, and enabling accelerated production. Underbalanced technology, while still on a sharp growth curve, is finally becoming accepted as a normal method for handling the drilling and completion of wells. This paper details the benefits and limiting factors of UBD technology, underbalanced fluid system selection, and UBD techniques, as well as candidate screening and selection.
Experimental Study of Formation Damage during Underbalanced-Drilling in Naturally Fractured Formations  [PDF]
Siroos Salimi,Ali Ghalambor
Energies , 2011, DOI: 10.3390/en4101728
Abstract: This paper describes an experimental investigation of formation damage in a fractured carbonate core sample under underbalanced drilling (UBD) conditions. A major portion of this study has concentrated on problems which are often associated with UBD and the development of a detailed protocol for proper design and execution of an UBD program. Formation damage effects, which may occur even if the underbalanced pressure condition is maintained 100% of the time during drilling operation, have been studied. One major concern for formation damage during UBD operations is the loss of the under-balanced pressure condition. Hence, it becomes vital to evaluate the sensitivity of the formation to the effect of an overbalanced pulse situation. The paper investigates the effect of short pulse overbalance pressure during underbalanced conditions in a fractured chalk core sample. Special core tests using a specially designed core holder are conducted on the subject reservoir core. Both overbalance and underbalanced tests were conducted with four UBD drilling fluids. Core testing includes measurements of the initial permeability and return permeability under two different pressure conditions (underbalanced and overbalanced). Then the procedure is followed by applying a differential pressure on the core samples to mimic the drawdown effect to determine the return permeability capacity. In both UBD and short pulse OBP four mud formulations are used which are: lab oil, brine (3% KCL), water-based mud (bentonite with XC polymer) and fresh water. The return permeability measurements show that a lab oil system performed fairly well during UBD and short OB conditions. The results indicate that a short overbalance pressure provides a significant reduction in permeability of the fractured formations. In most tests, even application of a high drawdown pressure during production cannot restore the initial permeability by more than 40%.
A Simple Analytical Approach to Simulate Underbalanced- drilling in Naturally Fractured Reservoirs—The Effect of Short Overbalanced Conditions and Time Effect  [PDF]
Siroos Salimi,Ali Ghalambor,Johan Tronvoll,Knut Inge Andersen
Energies , 2010, DOI: 10.3390/en3101639
Abstract: This paper describes an analytical approach to investigate the nature of short overbalanced conditions and time effects during underbalanced drilling (UBD) in a naturally fractured reservoir. This study uses an analytical model which is developed for kinetic invasion of mud into the fractures. The model is based on fluid flow between two parallel plates, which is further extended to model the fluid flow in a fractured formation. The effect of short overbalanced pressure and the time effect during UBD as well as the aspects of well productivity and flow efficiency are explained. This model is an Excel-based program and provides a fast and convenient tool for analysis and evaluation of drilling conditions (mud properties, time, and pressure of drilling) in a fractured formation. The model can also predict the impact of the fracture and mud properties on the depth of invasion in the fractured formations.
The Outline and General Comments about the Advance of the Resevoir Geophysics Project Implemented in Daqing Oilfield

LI You-ming,

地球物理学进展 , 2006,
Abstract: Shortly after the constitution of this project,in order to verify the feasibility of the theoretical research implementation,we proposed an additional requirement of direct involving in the production of oil and gas reservoirs in the outer part and deep part of Daqing,so that the overall merit of both theoretical research and practical application of this project can be improved.With the successful construction of PC-clusters and development of the seismic data parallel processing system plus assistant software packages in 1998,we built up the 3D wave equation pre-stack depth migration algorithm and the corresponding software in 2000,which is synchronous with international seismic exploration community.Such an achievement greatly improves the capability of seismic imaging in China.In the year of 1999,we assembled an eight-node PC-cluster and processed 150 km-long seismic profiles.In paticular,on the depth map of line 82,we clearly imaged the internal structure and fault character of an uplift in a depression area.After a rearrangement of 3D seismic exploration and with many research works,a great break through was achieved accomanying the drilling of the Xushen No.1 well and leading to the discovery of the huge gas field in Daqing.This success remarkably improves the continuable development foreground of Daqing oilfield.We have also built up two reservoir geophysics research centers in Beijing and Daqing,respectively.It has been proved that proper and reasonable research organization and activity will benefit the integration and application of the products of a great scientific project,and is key to make progress with combined efforts consecutively and efficiently.
A Study on Alkali Consumption Regularity in Minerals of Reservoirs During Alkali(NaoH)/Surfactant/Polymer Flooding in Daqing Oilfield
Zhenhai JIANG,Qingjie ZHANG,Jianguang WEI,Yunsong GAO
Advances in Petroleum Exploration and Development , 2012, DOI: 10.3968/2404
Abstract: In the process of oil displacement of ASP (Alkali/ Surfactant/Polymer) flooding , when Alkali interacts with the fluid and minerals of the reservoir, the alkali is subject to be consumed. The consumption regularity is the key factor affecting ASP ingredient, injection plan, scaling regularity for production wells and oil displacement effectiveness. Therefore to study the alkali consumption is of great significance in guiding ASP ingredient, injection project design, and the analysis for oil displacement mechanism. In this paper, aiming at the main components of minerals in the reservoir in Daqing Oilfield, the laboratory study on static alkali consumption for five kinds of minerals (kaolinite, grundite, chlorite, feldspar and quartz) in ASP system and single component NaOH solution are done respectively. The alkali consumption regularities for five kinds of minerals in ASP and single component NaOH solution are concluded. The research indicates that the amount of alkali consumption for kaolinite, grundite, chlorite, feldspar and quartz is changing from larger to less accordingly, but is mainly caused by clay minerals; the average alkali consumption is 18.3% higher than that by matrix minerals. In single component NaOH solution, the alkali consumption styles of clay minerals and the matrix minerals take the chemical reaction as the lead, and the physical adsorption as the second. In ASP system solution, the alkali consumption style of clay minerals, takes the physical adsorption as the lead, and of matrix minerals takes the chemical reaction as the lead. In ASP solution, compared with single component solution, polymer and surfactant have the functions of restraint to alkali consumption in minerals of the reservoir, and the amount of alkali consumption decreases evidently. Key words: Alkali; Surfactan; Polymer; ASPl; Oil displacement
The Performance of Polymer Solution Added with Viscosity Stabilizer and the Evaluation of Its Oil Displacement Efficiency in Daqing Oilfield  [cached]
Jianguang WEI,Qingjie ZHANG,Zhenhai JIANG,Haijun ZHANG
Advances in Petroleum Exploration and Development , 2012, DOI: 10.3968/2401
Abstract: Aiming at the low viscosity of polymer solution, which is compounded with fresh water but diluted with produced water, and at the problems concerning oil displacement efficiency, an onsite test on polymer solution with viscosity stabilizer (PSVS) is carried out. As a result, it has great and guiding significance to the application and popularization of viscosity stabilizer by studying the performance of polymer solution with viscosity stabilizer and its influence on oil displacement efficiency. In this paper, aiming at two different kinds of polymer solutions among which one is compounded with fresh water but diluted with fresh produced water and the other with aerated produced water, two laboratory evaluative tests concerning viscosity stabilization, anti-shear stability, fluidity, and absorbability of polymer solution as well as its oil displacement efficiency are done. The results of onsite application of PSVS are traced and analyzed. The viscosity stabilization of the polymer solution adding with viscosity stabilizer becomes much better than that of the normal polymer solution. The resistance and the residual resistance factors, the static oil sand adsorption rate and the dynamic core adsorption rate of the solution are all increased markedly. The working viscosity and oil displacement efficiency are improved markedly as well. In comparison with the polymer solution diluted with fresh produced water, the polymer solution diluted with aerated produced water is much better in terms of viscosity stabilization. Comparing with the normal polymer solution with viscosity stabilizer before sheared, the polymer solution which is sheared before adding with viscosity stabilizer performs obviously better in terms of viscosity stability. In contrast to the adjacent block injected with normal polymer solution, the block under onsite flooding test with injection of PSVS features that the average injection pressure increases slightly but keeps steady, the recovery speed of the average monthly water cut of production wells slows down, the thickness of the absorptive layers increases, and the periodic recovery rate improves as well. Key words: Polymer solution; Viscosity stabilizer; Daqing oilfield

CHEN Lin,SUI Xin-guang,TAO Jia-sheng,LI Fu-jun,

腐蚀科学与防护技术 , 2007,
Abstract: By chemical examination in laboratory and test in situ, we found that the CI^- content and SO^2-4 content are higher in Daqing oilfield, and the variation of the soil resistivity is bigger. The soils show strong corrosivity along longitudinal depth to steel equipments. By means of contact test with a reference electrode underground, we measured the distribution of casing protection potential along vertical depth. The results indicate that the casing protection potential curve is smooth, and the protection potential is lower than -850 mV. The casing protection current can polarize up to 10000 cm in depth. The bracelet anode and the casing can installed or repaired simultaneously in the fled with no additional troubles and cost to the conventional field operation, therefore, it is of applicable value.
Cooperation System of Oilfield Exploration Well Operation Management

JIN Gang,MIN Jie,SU Qing-Lin,WU Jun,YANG Ji-Bin,

计算机系统应用 , 2010,
Abstract: Exploration well operation management system standardizes management norms of work nodes and information criteria by reorganizing and optimizing operation management workflow of pre-exploration wells, regional exploration wells, and appraisal wells in Daqing Oilfield under the framework of Daqing cooperation work platform. The system involves not only worksite design, exploration well drilling, geological logging, geophysical logging, seismic VSP logging, reservoir testing, reservoir stimulation and oil and gas well production test, but also scientific research and step-by-step approval of each design before and after engineering implementation and final acceptance of research achievement. The system integrates all specialties together into a platform, and combines work flow and data flow of exploration well operation management, so as to realize unified operation management, database building and data application of exploration wells and also achieve generation, integrated application and sharing of data. This is the first system in China for exploration wells operation management.
Scientific Drilling of the Terrestrial Cretaceous Songliao Basin
Yongjian Huang,Cheng-Shan Wang,Terrestrial Scientific Drilling of the Cretaceous Songliao Basin Science Team
Scientific Drilling , 2008, DOI: 10.2204/iodp.sd.6.11.2008
Abstract: Investigations of critical climate changes during the Cretaceous have the potential to enhance our understanding of modern global warming because the extreme variances are the best-known and most recent example of a greenhouse Earth (Bice et al., 2006). Marine Cretaceous climate archives are relatively well explored by scientific ocean drilling programs such as the Integrated Ocean Drilling Program (IODP) and its predecessors. However, Cretaceous terrestrial climate records are at best fragmentary (Heimhofer et al., 2005). The long-lived Cretaceous Songliao Basin of NE China is an excellent candidate to fill this gap and provide important ocean-continent linkages in relation to environmental change (Fig. 1). This basin, located within one of the largest Cretaceous landmasses (Scotese, 1988), acted for about 100 million years as an intra-continental sediment trap; the present-day area of the basin is about 260,000 km2. It provides an almost complete terrestrial sedimentary recordfrom the Upper Jurassic to the Paleocene (Chen and Chang, 1994). Large-scale geological and geophysical investigations of lacustrine sediments and basin structures demonstrate that a rich archive of Cretaceous paleoclimate proxies exists. For example, the basin includes the Jehol Biota, a terrestrial response to the Cretaceous oceanic anoxic events (OAEs), and a potential K/T boundary (Qiang et al., 1998). An ongoing drilling program is supported by the Ministry of Science and Technology of China and by the Daqing Oilfield. It allowed for recovering of nearly complete cores from Upper Albian to the Uppermost Cretaceous in two boreholes (SK-I, SK II; commenced in 2006, Fig. 1). However, the older Cretaceous sedimentary record of Songliao Basin has not yet been cored. For that reason, a scientific drilling program has been proposed to the International Continental Scientific Drilling Program (ICDP) to sample the deeper sedimentaryrecord of the Songliao Basin through a new drill hole (Figs. 1 and 2).

LI Fu-jun,REN Cheng-feng,ZHANG Jian-jun,CHEN Yue-xun,

腐蚀科学与防护技术 , 2007,
Abstract: In view of the fact that corrosion induced leakage of casings gets much severe year by year of oil - water wells in Daqing oilfield, we put forward the anticorrosion methodology of sacrifice anodes, and the technology is the serial anodes are buried on the flank of the working casing of oil-water wells. Through simulation experiment in the laboratory, it follows that in case the water electric resistivity is appoximately egual to the cathode-anode area ratio, anodes should be buried underground with a depth of 3000 cm-5000 cm, the way of anodes combination is connection in series-parallel, and it would come into being the bigger electric current output and the good potential distribution. The suitable spacing between of anode and cathode ranges around 900 cm.
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