Giant CBM Field Proven in Shanxi

Qinshui Coalbed Methane Field, the largest one in China, was recently found in the southern part of Qinshui basin in Shanxi Province. Based on the appraisal by experts organized by Ministry of State Land and Resources, the field has a CBM-bearing area of 164.2 square kilometers with the proven geological reserves of 40.210 billion cubic meters and the recoverable reserves of 21.839 billion cubic meters. The field can establish a production capacity for 1 billion cubic meters per year. The CBM field has a stable distribution of CBM layers and abundant reserves. Currently,a total of 29 well have been drilled, of which the highest single-well production is 16000 cubic meters per day. The tested well group is under trial production.……     

Sinopec to Acquire Maoming Petrochem Giant

Sinopec Corp. is considering a plan to purchase Maoming Petrochemical Company from its parent company next year, said Zhang Jiaren, director and vice president of Sinopec Corp. Maoming Petrochemical Company in Guangdong Province is one of the country's two oil refining enterprises with the production capacity exceeding 10 million tons.Zhang Jiaren said three companies under Sinopec-Maoming Petrochemical Company, Tianjin Petrochemical Company and Luoyang Polyester Company are the targets for acquisition, but Maoming is most mature for acquisition at present time because of its normal production and promising     

Multistring analysis of wellhead movement and uncemented casing strength in offshore oil and gas wells

This paper presents a theoretical method and a finite element method to describe wellhead movement and uncemented casing strength in offshore oil and gas wells.Parameters considered in the theoretical method include operating load during drilling and completion and the temperature field,pressure field and the end effect of pressure during gas production.The finite element method for multistring analysis is developed to simulate random contact between casings.The relevant finite element analysis scheme is also presented according to the actual procedures of drilling,completion and gas production.Finally,field cases are presented and analyzed using the proposed methods.These are four offshore wells in the South China Sea.The calculated wellhead growths during gas production are compared with measured values.The results show that the wellhead subsides during drilling and completion and grows up during gas production.The theoretical and finite element solutions for wellhead growth are in good agreement with measured values and the deviations of calculation are within 10％.The maximum von Mises stress on the uncemented intermediate casing occurs during the running of the oil tube.The maximum von Mises stress on the uncemented production casing,calculated with the theoretical method occurs at removing the blow-out-preventer （BOP） while that calculated with the finite element method occurs at gas production.Finite element solutions for von Mises stress are recommended and the uncemented casings of four wells satisfy strength requirements.     

Large Oil Field in Bohai Bay Put into Production

The first-stage project of Qinghuang-dao 32-6 oil field,located in the central part of Bohai Bay and about 130 kilometers east of Tanggu, has been put into production in October this year. A total of 29 production wells went on stream. CNOOC holds a 51 percent stake in this oil field while Texaco and BP have the remaining 49percent, each with 24.5 percent.……     

Advance in Novel Resin Catalyst for Manufacture of Bisphenol A

The project ＂Preparation of novel resin catalyst for manufacture of bisphenol A＂ jointly undertaken by the Jiangsu Technology College and Tianjin Shuangfu Fine Chemicals Company, Ltd. has made great strides. Bisphenol A is an important raw material for manufacture of epoxy resins, polycarbonates and combustion retarders, and the global output of this chemical is around 3.2 Mt/a. For a long time several foreign companies have monopolized the technology for production of bisphenol A, and China has to import a large amount of bisphenol A. Till now the bisphenol A production capacity in China is merely 50 kt/a.     

Simplified graphical correlation for determining flow rate in tight gas wells in the Sulige gas field

The Sulige tight gas reservoir is characterized by low-pressure, low-permeability and lowabundance. During production, gas flow rate and reservoir pressure decrease sharply; and in the shut- in period, reservoir pressure builds up slowly. Many conventional methods, such as the indicative curve method, systematic analysis method and numerical simulation, are not applicable to determining an appropriate gas flow rate. Static data and dynamic performance show permeability capacity, kh is the most sensitive factor influencing well productivity, so criteria based on kh were proposed to classify vertical wells. All gas wells were classified into 4 groups. A multi-objective fuzzy optimization method, in which dimensionless gas flow rate, period of stable production, and recovery at the end of the stable production period were selected as optimizing objectives, was established to determine the reasonable range of gas flow rate. In this method, membership functions of above-mentioned optimizing factors and their weights were given. Moreover, to simplify calculation and facilitate field use, a simplified graphical illustration （or correlation） was given for the four classes of wells. Case study illustrates the applicability of the proposed method and graphical correlation, and an increase in cumulative gas production up to 37% is achieved and the well can produce at a constant flow rate for a long time.     

CNOOC Maintains Sustainable Business Development

CNOOC Limited, China＇s top offshore oil producer, announced in mid-May that a new oil field in South China Sea area has been successfully brought on stream with the daily oil production exceeding 2100 barrels. Weizhou 11-1, an independent oil field located in the western part of South China Sea and southwest of Weizhou Island in the Beibu Gulf, is adjacent to other two producing oil fields-Weizhou 11-4 and Weizhou 12-1, with the water depth ranging from 30 meters to 40 meters. Currently, there is only one platform in Wizhou 11-1. Its development and production are mainly based on the facilities and submarine pipelines of the adjacent oil fields.     

To Overseas Readers

Natural Gas Industry is China's only comprehensive periodicalwhich specially reports the technical theories and field experlences athome on the exploration, development, and surface construction ofgas fields, drilling and production technology and equipments of gaswells, storage, transportation, processing and utilization of gas, energysaving, environmental protection, management and administration as     

Modeling optimal oil production paths under risk service contracts

Due to the rigorous fiscal terms and huge potential risk of risk service contracts,optimizing oil production paths is one of the main challenges in designing oilfield development plans.In this paper,an oil production path optimization model is developed to maximize economic benefits within constraints of technology factors and oil contracts.This analysis describes the effects of risk service contract terms on parameters of inputs and outputs and quantifies the relationships between production and production time,revenues,investment and costs.An oil service development and production project is illustrated in which the optimal production path under its own geological conditions and contract terms is calculated.The influences of oil price,service fees per barrel and operating costs on the optimal production have been examined by sensitivity analysis.The results show that the oil price has the largest impact on the optimal production,which is negatively related to oil price and positively related to service fees per barrel and operating costs.     

Estimation of the current stress field and fault reactivation analysis in the Asmari reservoir, SW Iran

Knowing the current condition of the faults and fractures in a reservoir is crucial for production and injection activities.A good estimation of the fault reactivation potential in the current stress field is a useful tool for locating the appropriate spot to drill injection wells and to calculate the maximum sustainable pore pressure in enhanced oil recovery and geosequestration projects.In this study,after specifying the current stress state in the Gachsaran oilfield based on Anderson's faulting theory,the reactivation tendency of four faults(F1,F2,F3,and F4)in the Asmari reservoir is analyzed using 3D Mohr diagrams and slip tendency factors.Results showed that all the faults are stable in the current stress state,and F2 has the potential to undergo the highest pore pressure build-up in the field.On the other hand,F3 has the proper conditions(i.e.,strike and dip referring to σHmax orientation)for reactivation.Stress polygons were also applied to show the effect of the pore pressure increase on fault stability,in a graphical manner.According to the results,the best location for drilling a new injection well in this part of the field is the NW side of F2,due to the lower risk of reactivation.It was found that both methods of 3D Mohr diagrams and slip tendency factors predict similar results,and with the lack of image logs for stress orientation determination,the slip tendency method can be applied.The results of such studies can also be used for locating safe injection points and determining the injection pressure prior to numerical modeling in further geomechanical studies.     

油气田(井)开发生产全过程分析新方法

基于油气田（井）开发过程中产量数据的变化形态，提出了一种由高等数学理论公式推演出的适合于油气田（井）开发全过程拟合及预测分析的方法。认为已发表的拟合及预测油气田（井）产量的文章中，所引用的计算实例大多经过精心挑选，而现场实际生产数据是有波动的，特别是油气田（井）开发过程中含有开发战略思想调整等人为因素时，产量数据的上下波动更显著。作者采用前苏联北塔夫罗波夫佩拉基阿金气田１９５７～１９７７年的生产数据和我国白杨河油田（开发４０余年，已进入枯竭期）的生产数据，未作任何校正和修改，直接用于文中的实例计算。白杨河油田生产数据的拟合效果参数为５．４％，表明该方法计算简便快捷，拟合预测的准确性较高，平均相对误差仅１．０５％，具有较强的实用价值。表２参３（陈志宏摘）     

四川气田气井产量递减规律探讨

文中对影响气井产量递减的因素进行分析,在不同类型递减气藏中选出一批井,根据油气井递减基本规律,进行产量回归研究,得到一些新的认识,即四川气田大多数气井产量递减不仅符合指数递减,同时也符合双曲线递减;在产气量预测中,双曲线预测结果好的井几乎为气水同产井,指数式预测结果好的井几乎为纯气井,这将为四川气田气井以后的产能预测工作起到积极的指导作用。     

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油气田产量和可采储量的预测是油藏工作中一项十分重要的任务，它是编制油气田开发规划部署，进行油气田开发（调整）方案设计，以及油气田开发动态分析的重要内容。基于对大量油气田开发实际动态资料的统计研究，建立了一种预测油气田产量、累积产量、可采储量、最高年产气量及其发生的时间的新模型。该模型还可以预测剩余可采储量、剩余可采储量的储采比或采油速度等参数。油气田实际应用结果表明，该模型不仅适用于油气田产量存在单峰的情形，而且也适用于油气田投产之后持续递减的情形。     

基于Gompertz的灰色模型预测油田产量

随着我国合作开发的海外油田项目日益增多,从目前和长远来说,快速预测油田产量,对于项目的正确评估是一项重要任务。基于Gompertz模型可以很好表征和描述“S”型曲线的特点,以及灰色模型建模适用数据点较少的优点,提出一种基于Gompertz的灰色模型用以预测油田累计产量的新方法。经实例验算,该模型回归拟合历史数据具有强的抗干扰能力,拟合精度高;利用基于Gompertz的灰色模型预测油气田产量具有一定的准确性和可靠性。     

油气田产量预测的新模型

基于累积产量随时间递增的信息特征及对以往产量预测模型的研究，建立了一种预测油气田产量、累积产量和可采储量的新模型。该模型可以对油气田开发全过程的开发指标进行拟合与预测，并可简化为Logistic模型和胡一陈模型。用前苏联巴夫雷油田和北斯塔夫罗波尔一佩拉基阿金气田的实际数据验证的结果表明，该模型预测精度较高。表2参10     

低渗透气藏产量递减规律分析

从 Arps 的基本递减规律出发,提出了一种低渗透气藏递减规律的简单分析方法。指出了低渗透致密气藏气井递减率并非恒定不变,对衰减递减方程进行变形并推导出产量预测模型,对模型中的系数进行修正,使其能很好地拟合实际生产数据。此方法以月为单位使计算更加准确、合理。通过油田实际应用表明,该方法简单、可靠、实用,对于产量波动较大的低渗透和特低渗透气藏尤为适用。     

油气田剩余可采储量、剩余可采储采比和剩余可采程度的年度评价方法

剩余可采储量、剩余可采储采比和剩余可采程度是判断油气田当前开发形势的重要指标,是决策是否进行开发调整的重要基础,因而受到全球各石油公司的高度重视。根据中国行业标准,评价可采储量的方法主要包括水驱曲线法、产量递减法和预测模型法。水驱曲线法仅适用于水驱开发的油田,而产量递减法和预测模型法则适用于已经进入递减阶段的任何储集类型、驱动类型和开采方式的油气田。DeGolyer and MacNaughton和Ryder Scott两家评估公司对中国境内油气田的剩余经济可采储量进行年度储量资产价值评价所使用的方法是由美国证券交易委员会多部门团队提供的Arps指数递减的变异公式。利用适用于不同开发模式的广义指数递减法,推导得到了油气田年度经济可采储量、剩余经济可采储量、技术可采储量、剩余技术可采储量、剩余可采储采比和剩余可采程度的计算公式,并对DeGolyer and MacNaughton公司使用的变异指数递减法进行了说明和评价。通过8个油田实际应用结果表明,笔者提供的计算方法实用有效。     

预测页岩气井产量和可采储量泛指数递减模型的建立及应用

随着中国页岩气工业的发展和大量页岩气井的投产,如何有效地预测页岩气井的产量和可采储量已成为油气藏工程的重要课题,也是页岩气资源的生产和管理部门极为关心的问题.由于页岩气是以吸附状态和自由状态分别储存于超致密页岩基质和次生裂缝系统中,而页岩气井在钻井、完井、测井和压裂过程中受到泥浆的多次污染.因此,投产后的页岩气井表现出...     

油井压裂前后产量递减规律预测方法

采用非线性回归和多元线性回归数学方法,建立了以指数递减规律来描述油井压裂前、后产量递减规律的数学模型。利用该方法所建立的模型,可实现对特定区块压裂油井的产量历史拟合及预测。为确定油井压裂增油效果和有效期,以及评估整个油田开发经济效益提供理论依据。将该方法应用于南一区块,结果表明,由于单井按指数回归的曲线能较好地描述采油指数的动态递减规律,因此模型拟合结果压前符合率为71．4％,压后符合率为74．7％。     

油气田产量预测模型的理论研究和应用

分析了Arps递减模型的递减特征和Weibull预测模型在递减阶段的递减特征,提出了一种预测油气田产量的通用模型:Q_t=at^q-1/(1+pbt^q)^1/p,当q=1时,该模型可简化为Arps递减模型;当p→0时,该模型又可简化为Weibull模型。该模型可用以描述开发全过程的产量变化规律和递减率变化规律,因此,适用于各类油气田产量的预测。