水淹层处理解释软件研究/

2019-04-17 15:59:41

method 测井 processing interpretation 解释



摘 要
大庆油田属河流——湖泊三角洲相沉积,储层非均质性严重,薄、差储层发育。在油田进入高含水期开发以后,剩余油分布类型复杂多样,呈高度分散状态。同时,由于储层经过长期注水冲刷,形成水淹通道,主力厚油层已经全面高含水。因此,开采对象已经从主力厚油层转向薄、差油层及对厚油层顶部剩余油进行三次采油。利用测井资料对中厚储层研究水驱后层间、层内的非均质性变化,进行厚层细分解释,准确划分未淹及低淹层段;对于薄、差层,要利用高分辨率技术提高测井资料识别薄、差层的能力,准确区分中低含水层与高含水层,提高水淹层剩余油饱和度解释精度,寻找剩余油相对富集区,为油田生产挖潜提供准确依据,已成为测井解释工作的重要任务和课题之一。
进入九十年代,已经研究成功了厚层细分层、薄差层水淹层解释方法。厚层细分层解释方法是利用测井资料和岩心分析资料建立解释模型。可以精细描述厚油层内不同部位的水淹状况及剩余油饱和度。解释模型采用先定性后定量的办法,可定量给出四个水淹等级并可提供一套较高精度的储层参数。薄层水淹层解释方法是针对薄差层平面延伸范围小、相变快,岩性物性极不稳定,统计分析方法不适用的情况,从理论分析入手,提出了双地层水电阻率模型,采用多重迭代递归方法来求解目前含水饱和度,并通过自由水饱和度统一不同岩性储层的水淹级别判断标准。受区域和层位限制小,适用范围广。
在测井资料处理解释软件方面,现有的测井资料处理解释软件主要还是以引进的处理解释系统为主,并主要是应用于探井资料处理与解释,缺乏能够满足水淹层处理解释特殊要求的软件系统。软件是方法的载体,已经研究完成的处理解释方法急需形成现实生产力。因此,针对油田开发面临的地质问题,结合测井技术的发展,开发测井资料水淹层处理解释系统,形成生产能力来满足油田日益迫切的生产需要已成为当务之急。
水淹层测井资料单井处理解释软件,采用 SUN 工作站作为硬件平台和 UNIX操作系统作为软件平台进行开发,用 C++和 Fortran 语言编程,以 X-Window 和 Motif 作为图形窗口系统和界面工具。完成了界面管理、数据管理、深度校正、厚度解释、分层取值、水淹层处理、交互处理解释以及成果图绘制等功能。充分的人机交互功能、友好的用户界面,可使测井分析家在调整井测井资料解释中无可替代的作用得到最大程度的发挥。
该软件系统在大庆油田采油1~7厂投入应用,累计安装软件近30套。经过大量生产井的实际生产应用,见到了明显的地质效果,提高了测井解释技术水平。实际生产情况统计表明,储层厚度解释精度在90%以上,水淹层解释也能够满足生产需要。处理解释结果可以方便的进入地质数据库。
测井资料水淹层单井处理解释软件在生产中应用后,缩短了测井资料处理时间,原来的厚度解释、水淹层解释及图纸上墨等工作现在由计算机一次完成,减轻了劳动强度,也缩短了资料的处理和周转时间,大大提高了工作时效。




Abstract
Daqing Oilfield is flvial-lake delta deposit. Thue heterogeneity of the reservoir is serious. Thin and bad reservoir develops commonly. After the oilfield entered the development period with high water-bearing, the type of remaining oil distribution is various and in high dispersion state. Meanwhile, the waterflood path is formed in the reservoir because of washout with long period of water injection and main thick oil layers are all in high water-bearing. The producing reservoir have shifted the third production from the main thick layers to thin, bad ones and on the top of thick layers gradually. It becomes important tasks and one of topics to research on heterogeneity of the inter layers and inner, interpreting on thick layers subdivision, identifying non-watered-out layers and low watered-out layers correctly with log data for middle/thick reservoirs, and to enhance the capability of identifying and interpreting the thin/bad layers by high-resolution technology, to identify different zones with high/low water-bearing, to improve the interpretation precision of remaining oil saturation, to seek the relative abundance zone of remaining oil for thin/bad reservoirs, to provide correct evidence for the production and potentialities of the oilfield.
In 1990s, we researched out the method for subdividing thick reservoirs and the interpretation method for thick and thin/bad reservoirs. The method for subdividing thick reservoirs is to establish the interpretation model on the basis of well logging data and core analysis data. This method can describe the watered-out degree and remaining oil saturation at different areas in thick layers precisely. By using the method of first qualitative analysis and then quantitative analysis, the model gives four watered-out degrees quantitatively and provides a set of reservoir parameters with high precision. For the thin watered-out zones, since the extension area is limited, the phase change frequently, the lithological properties vary, the statistical analysis method cannot be used properly. Therefore, a new model, double formation water resistivity model, has been proposed. Through this model water saturation can be described by the method of multi-iteration and recursion. The criterion for identifying watered-out degree of different lithological reservoirs can be unified by free water saturation. This method can be used in wide range of formations and not easily affected by conditions, such layers and areas.
For the log data processing and interpretation software, the introduced interpretation system for exploration wells has been the major interpretation software. It cannot process and interpret the data for the watered-out zones. Software is media of method. The processing and interpretation method is required urgently to turn into present productivity. New software needs urgently to combine with the mature data processing and interpretation method. Therefore, developing a processing and interpretation system on well logging data becomes crucial to meet the requirements of oilfield production.
The processing and interpretation software system on log data for single well in watered-out layers is developed on SUN work station as a hard base and UNIX operation system as a soft base, programmed by the language of C and Fortran, X-window and Motif as graphical windows system and interface. It can play roles on depth adjustment, thickness interpretation, processing by individual layers, watered-out zone processing, interactive processing and interpretation, etc.. This software system has powerful interactive functions and friendly user’s interface, enabling the well logging analyst to give full play to their professional knowledge.
After the completion of this project, more than 30 copies of this software have been installed and functioned in oil production companies from No.1 to No.7. The application on production wells has showed apparent geological effectiveness. Oil production companies have enhanced the technical level of well logging interpretation by transforming from manual method to computer processing. On-site production statistics shows that, reservoir thickness interpretation precision can be over 90% by processing automatically. For the watered-out layer interpretation, the conformity can meet the production requirements through interactive processing. The results can be input into geologic database conveniently.
The software application demonstrates that this method can shorten the data processing period. The thickness interpretation, watered-out layer interpretation and drawing drafting can be conducted on the computer almost simultaneously. It can reduce the labor intensity, also shorten the period for processing and turning over log data and improve the work productivity.