bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reservoir Characterization of Fractured Volcanic Gas Reservoir in Deep Zone
Authors: Ran Qiquan , Yuan Shiyi , Xu Zhengshun , Hu Yongle , Wang Yongjun 
Published: December 2007

Abstract
Quite a few large-scale volcanic gas reservoirs have been discovered in deep zone in Songliao Basin of North-East China in recent years. The consequent issue is how to produce this kind of gas reservoir effectively. Reservoir characterization is essential for the effective production of volcanic gas reservoir, which provides the geological basis for gas reservoir development. The geological scenarios of volcanic gas reservoirs are extremely complex, which is featured by quick changes of lithofacies and its thickness, distributions of fractures and pores/vugs, strong heterogeneity, changes of gas well productivities among different wells, etc. The difficulties of reservoir characterization pose a great technological challenge on effective production of volcanic gas reservoir. In this paper a systematic methodology is proposed for characterization of fractured volcanic gas reservoir based on a large amount of laboratory experiments, theoretical studies and field practices. The proposed methodology is a multi-discipline integration, including identification of lithologies and lithofacies, eruption period analysis and stratigraphic correlation, identification and evaluation of fractures, identification of volcanic body and reservoir prediction, well log interpretation for the dualporosity volcanic reservoir, discrimination of gas and water layer, reservoir appraisal and geological modeling, etc. These studies provide a strong base for making decisions on the reasonable well pattern and development plan.
A New Completion Technology with Separate Layer Fracturing and Commingled Producing in Gas Field
Authors: Gangdan Fu , Zhenfeng Zhao , Fenxia Zhao , Jie Gui , Changhao Yan , Yong Ren 
Published: December 2007

Abstract
In Changqing gas field, it is very usual that a gas well contains many gas bearing beds, whose property is different with each other. Because of the low formation pressure and low permeability, the nature rate is so small that every well must be treated. However, when treating these multi-layer wells, the conventional separate fracturing is not effective or cost-effective, and needs long time. To make all the beds treated effectively, to improve individual well producing rate and enhance economic benefit, optimizing several kinds of separate layer treatment technology and analyzing the feasibility of commingled producing in Changqing gas field. Through 3 years research and piloting, a new completion string has been introduced.
This new technology is achieved by plugging of the packers and opening of the sand blast sleeve. Using the technology and completion string, three formations can be fractured continuously, but needn't kill well. Firstly, perforating all the three gas layers at a time, at the same time assembling the completion string, then tripping it in the gas well; secondly, launching a ball to make packers set down, and fracturing the lower most layer; thirdly, launching a ball again to open the upper sand blast sleeve so that the upper layer is connected with the tubing and isolated with the sub layer, so the second layer can be fractured. Similarly, and the last layer can be treated like this step. Finally, when all the layers have been treated, unloading liquids of all layers, blowouting and producing. During fracturing, if sand plug happens, it can be solved by reverse washing. The strong point of this technology is that all the processes are made in the same string and needn't exchange string.
The technology has been used in about 150 gas wells till 2006, which indicates that it has advantage of favorable mechanical plugging, easy to implement, high rate of delivery, no damaged to formation, high completion well rate, low operating cost for single well. Therefore, the new completion technology and string is very perspective, especially for low permeable, low formation pressure gas reservoir.
This paper describes the principle, the parameater and function of each tool, operation procedure, advantages and application of using the technology.
The Oil Well Casing's Anticorrosion and Control Technology of Changqing Oil Field
Authors: Xu Yonggao , Yang Quan'an , Li Qiongwei , Chen Bihai 
Published: December 2007

Abstract
With the increasing oil production of Changqing oilfield, the casing's corrosion and damage have became more and more serious in producing and injection well system. After long term research, the corrosion mechanisms of casing were made sure, and two main technologies were developed to prevent the external and internal corrosion, respectively (Cluster wells’ CP and Epoxyn-bond tape plus zinc anode, Inner polymer coating and Downhole inhibitor injection facility). Three types of control technologies of well damage casing have been applied. The large scale applications of those technologies in Changqing oilfield not only inhibit the casing's damaged, and also keep the newly opened wells in a good condition. At last these new techniques guarantee the stable production of Changqing oilfield.
The Discussion About Software Demand Management and Development Standardization Management in a Chinese Oil Field
Authors: Yu Haiyan , Lu Dongfeng , Jiang Hongfu , Wang Tong , Cui Juncheng , Yang Haiying , Yuan Wencui , Zhu Ying , Shi Guojun 
Published: December 2007

Abstract
The next certain years, the main duty of information construction of the petroleum enterprise will be the omni-directional support oil industry core business. The software development and management in oilfield also will be important content of the oilfield information construction. Chinese oilfield cannot rely on domestic Software Company or foreign Software Company completely and blindly because of the specialization of the oilfield exploration development and the particularity of Chinese oilfield production and management. Absorbing the advanced software development management idea of Software Company, the Chinese oilfield should rely on own specialist and go out a path that suits the Chinese national condition and Chinese oilfield software development and management. In this process, the software development of Chinese oilfield has two weak sides at present: One is the software demand management; the other is development standardization management. This paper takes the Chinese some oilfield as an example, discusses with emphasis in view of the two weak sides in order to obtain the oilfield actual demand and standardization development.
A High-Efficiency and Low-Cost Exploration Data Management System
Authors: Li Ning , Wang Caizhi , Qiao Dexin 
Published: December 2007

Abstract
An exploration data management system, on which geologists, geophysicists and log analysts can work together with the same data source, is developed based on the broad band intranet environment now commonly used in oil enterprises and companies. In most cases, it is demanded that the operation visiting seismic data, log curves and remote images should be as simple, direct and batch as possible. For this reason, the design of our system is not depended on any commercial database. It is based on a simple data structure called CIF. In this way, we not only improve the visiting efficiency, but also reduce greatly the cost of the system installation and maintenance. Obviously, it gives a knowledgeable choice for those upstream oil enterprises and companies for their exploration data management. The server served in our system is a SunFire V490 with its Solaris 8 operating system. The end users, with their PC and Windows XP operating system, visit the data saved on NetApp hard disk array through 1GB fiber cable intranet. It is convenience for using the system to query and visit seismic, logging and remote data as well as several of multimedia files (such as .doc, .xls, .ppt, .jpg and .mpg etc.), and to display or download them. In 2005, the system was successfully installed and put into production in Research Institute of Petroleum Exploration & Development of
PetroChina in Beijing, and in China Petroleum Logging Co., Ltd. in Xian.
An Innovative Method: Risk Assessment for Exploration and Development of Oil and Gas
Authors: Chang Yuwen , Dou Hong'en , Chen Changchun , Wang Xiaolin , Liu Kun 
Published: December 2007

Abstract
This paper presents a new method and flowchart of risk assessment for the oil and gas upstream industry to identify and evaluate the risks in the oil and gas investment activities. It integrates several commonly used risk identification techniques, including fault tree analysis, brainstorming, and Delphi and event tree analysis methods. This paper divides the risk factors into three categories: social environment, natural environment and resources, technology and management, there are several risk factors in each category; therefore, a risk assessment system of the three hierarchies is built up. In the third hierarchy, a risk grade standard is established according to expected economic loss, which is determined by the risk probability and the consequence of the risk factors. A new method of the risk assessment was presented, Fuzzy Analytical Hierarchy Process (Fuzzy-AHP). The integrated risk grade of oil and gas exploration and development project can be obtained. In this method, the influence weight and the consequence of risk factors are comprehensively considered. It gives a significant reference for decision-makers of the oil and gas upstream industry. At present, this method has been recommended to the exploration and development risk assessment projects in the oilfields, China.
Quantification of Overbalance-Induced Invasive Damage and the Estimation of Equivalent Skin Effect on Production
Authors: Ramalho John , Wu Zhan , Vaidya Ravi N. , Suryanarayana P. V. 
Published: December 2007

Abstract
An important premise of underbalanced drilling (UBD) is the productivity improvement it delivers through mitigation of invasive damage. Characterization and quantification of such damage, therefore, becomes a pre-requisite for assessing the value delivered by UBD. Several methods are available to quantify damage. In this work, we use a novel approach that combines dynamic micro-scale reservoir simulations calibrated to special core tests to model the extent of invasive damage, and its impact on flow-back during production. The approach is based on special tests conducted on reservoir core, and a dynamic "micro-simulator" to model invasion during drilling. Special core tests designed to measure effects of overbalanced exposure to drilling fluids are first conducted. Inputs to the simulation model are based on careful interpretation of the core test results, and thus are calibrated to observation. Details of the approach were presented earlier by Suryanarayana, et. al. (SPE 95861). In this paper, we apply this approach to two field cases, and use the results to quantify the damage and its impact on production. The two field cases are discussed in detail. Both relative permeability and permanent damage effects are described. The dramatic effects of invasion on clean-up and long-term production are illustrated, thus demonstrating the incremental value of UBD in these cases. Damage can be modelled as an equivalent skin, based on the saturation and permeability profiles within the zone of invasion. Since the saturation and permeability effects are a function of location along the productive length as well as time, we obtain time- and spatially-dependent equivalent skin. The equivalent skin can then be used in field-scale reservoir models to compare different drilling and development options. The use of these results in designing an optimal drilling and completion plan to lock-in the value of UBD is demonstrated for the two field cases.
Air Injection and Waterflood Performance Comparison of Two Adjacent Units in Buffalo Field: Economic Analysis
Authors: Kumar V. K. , Gutierrez D. , Moore R. G. , Mehta S. A. 
Published: December 2007

Abstract
Buffalo Field covers a large area on the southwestern flank of the Williston Basin, in the northwest corner of South Dakota. In 1987, 8,000 acres of the field were divided into two units to initiate improved oil recovery operations with two different methods: air injection and waterflooding. After collecting 18 years of production history a comparison has been made between the two projects to determine the relative success of both units.
In a previous paper (SPE 99454) the technical comparison of the projects was discussed and the superiority of the air injection project was demonstrated. This second paper addresses the economic analysis of both projects in terms of economic parameters such as net present value, payout time, incremental profit and rate of return. A sensitivity analysis on some of the key drivers of the project economics namely oil price, operating cost and capital investment was also performed.
In spite of being technically less successful, the West Buffalo "B" Red River Unit (WBBRRU) under waterflooding has shown greater economic benefit over its "twin" West Buffalo Red River Unit (WBRRU) under air injection. This results primarily from the low oil prices (less than $20/bbl) experienced during most of the life of the projects.
This case study shows that for an air injection project to be successful not only technically but also economically, a sufficiently high oil price (greater than $25/bbl) is needed due mainly to the high operating costs and capital investment.
Air injection can be an economically attractive IOR process in large prospects, particularly in deep, high pressure, low permeability reservoirs where water injectivity is limited and other recovery processes become uneconomic.
Huff 'n' Puff Recovery Technique on Waterout Horizontal Wells
Authors: Wang Chunhong , Li Gaoming 
Published: December 2007

Abstract
After the bottom water breaks into a horizontal well, the traditional way to recover the left oil above the horizontal well is to plug in the section below water level (the horizontal section) and re-perforate in the vertical section. However, this practice loses the advantage of horizontal wells. This paper proposes a Huff and Puff recovery technique for horizontal wells after water breakthrough and this technique utilizes the whole horizontal well instead of just the vertical section to further the oil recovery. Huff and Puff process is a cyclic gas injection process often used to recover attic oil, which involves three steps: gas injection, shut-in and production. Through a parametric study, the important control parameters towards a successful Huff and Puff recovery project are identified. In the analysis, we consider the impact of hysteresis on modeling the recovery processes through a historydependent-modeling method taking into account of the hysteresis of both relative permeability and capillary pressure. The results indicate that ignoring the hysteresis can overestimate the recovery predictions up to 16%.
Optimal Well-Testing Strategy for Production Optimization: A Monte Carlo Simulation Approach
Authors: Bieker H. P. , Slupphaug O. , Johansen T. A. 
Published: December 2007

Abstract
Well testing may be performed to support many decisions including ones related to production optimization of an oil production system. In production optimization information such as gas oil ratio and water cut/water oil ratio is used to decide on, for example, which wells to prioritize for choking back/opening to avoid over-/underutilization of the production capacity. Since the reservoir properties change with time, the uncertainties of their estimated values increase with time, and eventually a new well test will be required. As the uncertainty in the estimates grows, so does the risk for prioritizing the wrong well(s) giving lower oil production rate than possible. A computer program is developed to decide which well to test based on historical test data. The program uses a Monte Carlo approach for identifying which well test is likely to lead to highest increase in the total oil production rate after the well test information is utilized to optimize the oil production. The computer program is applied to field data quantifying the benefits when applied to this specific field.
Estimating Major and Minor Natural Fracture Pattern in Gas Shales Using Production Data
Authors: Gaskari R , Mohaghegh S. D. 
Published: December 2007

ABSTRACT
The U.S. Geological Survey estimates tight-gas sands and shales may contain up to 460 trillion cubic feet (Tcf) of gas in the U.S. alone - almost three times the amount of currently proven gas reserves - and that some 135 Tcf may be technically recoverable. Since natural fractures are the main source of permeability in gas shales, key to producing this vast resource is locating areas where natural fractures are abundant. By placing infill wells in such locations operators can significantly increase gas recovery.
In most cases, in fields that produce from gas shales, monthly production rate is the only data that is available. This paper introduces a new strategy for estimation of major and minor natural fracture using production data.
The framework includes the use of Geographic Information System as an environment to analyze the production data where the preliminary estimation of natural fracture trends is developed. Then by superimposing the results of the preliminary estimation on reservoir quality indices developed using a fuzzy pattern recognition technique, the uncertainty associated with the initial estimation is reduced. This technique is validated using a set of gas shale wells in Kentucky and West Virginia.
New Techniques for Plunger Lift in Conventional and Nonconventional Gas
Authors: Morrow Stanley J. , Hearn William , Cisneros Ramiro 
Published: December 2007

Abstract
The interest in and demand for natural gas has dramatically shifted the focus for many operators in the past few years. Plunger lift, which for many years was viewed as a last resort, and somewhat of a nuisance, has gained an all time high in popularity, and effectiveness and applicability. Most of the guesswork in evaluating candidates has been replaced with exotic programs that combine Nodal analysis with performance based calculations.
In recent years both equipment and applications have improved, and the production range of plunger lift now includes many wells previously not possible to produce with plunger lift. Here we will examine the new technology utilized in tracking, evaluating, and troubleshooting plunger lift wells. Also several case studies on where previously difficult production is now commonplace, will be presented.
Optimal Infill Drilling Design for Marginal Gas Reservoirs Using a Simulation-Based Inversion Approach
Authors: Cheng Y. , McVay D. A. , Lee W. J. 
Published: December 2007

Abstract
Infill drilling plays an important role in revitalizing marginal oil and gas fields by adding new reserves and accelerating recovery. However, design of an infill drilling program is often a challenging task for these kinds of reservoirs. First, most such reservoirs are mature fields where data are scarce and reservoir characterization is very limited. It is not uncommon for only production data to be available in a marginal, mature field. Second, the design often has to deal with a large number of existing wells and evaluate hundreds or thousands of potential infill drilling candidates. Given the marginal nature of these fields, a conventional evaluation approach, such as detailed reservoir characterization and simulation, is usually prohibitively time-consuming and costly. Furthermore, when designing an infill drilling program, well interference or acceleration effects have to be taken into account to reliably identify the potential for new reserve additions. Thus, an optimal infill drilling design procedure that adequately addresses these issues is extremely important.
In this paper, we present a systematic methodology for efficient design of an infill drilling scheme for marginal gas reservoirs. The approach consists of two major components. The first is a sequential inversion algorithm for rapid history matching. The algorithm is conditional to the correlation between permeability and porosity, if any. The inversion provides not only the spatial distribution of both permeability and pore volume, but also the spatial distribution of remaining gas in place. The second component of the approach is a successive selection strategy for infill candidate locations. The method fully addresses well interference effects between existing and infill wells, as well as interference between infill wells.
The approach is rapid and cost effective, and provides answers to critical questions such as: given certain economic criteria, how many wells should be drilled; where should the wells be drilled; what production performance can be expected; what will the incremental gas recovery be; and what will the acceleration effect be? Synthetic and field examples are provided to demonstrate the applicability and power of the method.
Improving Cement Bond in the Appalachian Basin With Adjustments to Preflush and Spacer Design
Authors: Newhall Chandler 
Published: December 2007

Abstract
Cement bond quality is imperative for all phases in the life of a well. Achieving a superior cement bond can be an engineering challenge in areas with naturally fractured formations. Often there is a driving force to lose the cement slurry to the fractures or for the slurry to be contaminated by formation fluid flowing into the wellbore from the fractures. Failure to effectively isolate these zones can be extremely costly over the life of the well. An inadequate cement bond can result in interzonal gas and liquids migration within the annulus, negatively impacting the recovery of hydrocarbons and increasing downhole scaling and corrosion tendencies. In severe cases, subterranean fluids can flow along the annulus all the way to the surface of the well, resulting in environmental contamination and expensive remediation.
This paper addresses how adjustments to pre-flushes and spacers have improved cement bond quality in the Appalachian basin. When drilling in the Appalachian basin, encountering hard sandstone, fractured shale, and coals with low pore pressure gradients is very common. The fractured shales and coals may present problems when cementing the well. These problems include cement dehydration due to excessive fluid loss or formation "breakdown," in which whole cement slurry is lost to a created hydraulic fracture. When this situation is encountered, it can be difficult to achieve proper cement tops and cement bond quality can be poor.
Field data was collected from Gilmer County, West Virginia. In the study area, the wells were drilled to the Alexander formation with compressed air. Cement jobs were historically pumped with the following schedule: gelled water, cement slurry and displacement. A re-engineered pump schedule now includes a dual chemical-spacer system ahead of the cement slurry. The leading spacer was a mixed cleaner/surfactant solution, and the trailing spacer was a filtrate-reduction solution that also enhances cement adhesion to pipe and formation. Approximately five days following the completion of both cement jobs, cement bond logs (CBL) were run on the wells and the results of each were compared.
As evidenced by the comparative analysis of the CBLs, the adjustment in the pre-flush/spacer design resulted in a marked improvement in the quality of the cement bond. These results are documented in the paper. The resulting impact of the modified design on well completion and operating costs are also reviewed. Mitigation of any environmental risks are quantified.