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RESERVOIR MONITORING Reservoir Monitoring is a new technology that has created growing interest over the pas two years. It is the application of multiple surveys of reflection seismology integrated with reservoir description and reservoir simulation, solved at each timelevel in an iterative manner, to track the movement of fluid saturations in a petroleum reservoir. Reservoir Monitoring includes both the measuxement of past and current location of fluids and the prediction of how the fluids will move in the future.
Yong, Li (Research Institute of Petroleum Exploration and Development, PetroChina) | Qi, Zhang (Research Institute of Petroleum Exploration and Development, PetroChina) | Chenji, Wei (Research Institute of Petroleum Exploration and Development, PetroChina) | Benbiao, Song (Research Institute of Petroleum Exploration and Development, PetroChina)
Abstract Understanding reservoir stacked styles is critical for a successful water injection in a carbonate reservoir. Especially for the giant carbonate reservoirs, different regions with different reservoir architecture stacked patterns developed may be applied to different development options. So reservoir stacked pattern characterization are especially important for the giant carbonate reservoir. This paper propose a systematic method of dynamic characterization on different reservoir stacked pattern, which applied to a giant carbonate reservoir in Middle East. This paper focuses on a giant carbonate reservoir, which is a Cretaceous carbonate reservoir in Middle East, with conducting waterflooding pilots currently. Thief zones are developed in this reservoir. Four patterns of reservoir architecture stacked style are classified based on geological study. Then the proposed systematic dynamic characterization method are applied, which mainly based on the dynamic data analysis (production data, formation test pressure, production logging test data etc.) and reservoir engineering methods (material balance analysis, well test analysis). Finally, distribution of the four patterns are mapped combined geological and dynamic understanding. The four patterns have distinctive geological features and dynamic characteristics. For example, pattern A are mostly composed by good quality reservoirs with high production rate for most intervals. Pressure gradient has almost no change from top to bottom, and well test log-log curve shows typical homogeneous reservoir characteristics. And OOIP of pattern A well is large with drainage radius mostly larger than 900m. While from pattern A to pattern D, poor reservoir and barriers increase, which change from massive reservoir to multi-layered reservoir. For pattern D, pressure gradient are separated as zigzag curve, and boundary response is clearly shown in well test log-log curve. Well OOIP and well drainage radius become smaller. After systematic dynamic characterization, reservoir architectures of all wells are calibrated and validated with geological results, and lateral distribution of architecture patterns are mapped. This paper offers a case study of systematic dynamic characterization of reservoir architectures for carbonate reservoirs. And understanding of reservoir architectures is much valuable for the next development options decision, which means different waterflooding well pattern, well type etc. are applied to different reservoir architectures. It also provides a methodology and reference case for engineers and geologists to investigate on other similar fields.
Petroleum reservoir simulation is the application of software designed to model fluid flow in petroleum reservoirs. I first encountered reservoir simulation while working on a project to store solar energy in an aquifer. During the first 3 years of my career, I performed a model study of a relatively small oil reservoir, reviewed the status of naturally fractured reservoir simulators, conducted an analysis of multidimensional numerical dispersion, evaluated the feasibility of developing geopressured/geothermal reservoirs, and compared the relative merits of different chemical flood processes. I thus found that a career in reservoir simulation would provide interesting challenges in a wide range of applications. The process of petroleum reservoir simulation is an aspect of reservoir management.
Abstract Effective Reservoir Management of a large gas condensate recycling field requires early recognition of the degree of communication between injectors and producers, aquifer strength and management of the key reservoir uncertainties. The objective of this paper is to communicate the requirement, acquisition, justification, applications and value of pressure data to improve reservoir management of the Goodwyn field. P. 251
Abstract The most prominent aspects of carbonate reservoirs are their heterogeneity, variable wettability and dual pore network, which collectively contribute to complex fluid flow and uncertainty in reservoir performance and recovery efficiency predictions. A review of ultimate recovery efficiency in 250 mature carbonate fields from around the world provides constraints for quantifying uncertainty in recovery efficiency predictions. Key determinants of ultimate recovery are fluid type, pore network, reservoir heterogeneity, drive mechanism and wettability. Development strategies and reservoir management techniques play crucial roles in maximizing expected ultimate recoveries for given reservoir/fluid parameters. Five main fluid type/carbonate reservoir classes, with characteristic ultimate recovery distributions and controls are:heavy and viscous oil reservoirs, in which recovery factor (RF) is controlled by fluid viscosity variations, field size and application of horizontal drilling, karstic/fractured carbonate oil reservoirs, in which RF is controlled by fracture intensity, matrix permeability, wettability and drive mechanism, conventional carbonate oil reservoirs, in which RF is controlled by reservoir connectivity, permeability and mobility ratio, organic buildup oil reservoirs, in which RF is controlled by nature and size of organic buildups and diagenetic modifications, and gas/condensate reservoirs, in which RF is controlled by aquifer encroachment and condensate drop-out. Examination of actual case histories reduces uncertainty in predevelopment recovery efficiency predictions and shows what is possible in new or old fields. Introduction Carbonate reservoirs are notorious for their generally low and variable recovery factors. This, together with unpredictability in reservoir geometry, continuity and quality, often leads to great uncertainty in evaluating the economic potential of carbonate prospects. Lack of consistent criteria and reliable data for the definition and calculation of recovery factors creates further problems. Historically, a large portion of the original geologic and reservoir engineering investigations in the petroleum industry dealt with physical principles involved in the production of oil and gas in clastic reservoirs with intergranular porosity. Most of this knowledge can also be applied to conventional carbonate reservoirs with interparticle or intercrystalline porosity. However, for carbonate reservoirs with a dual pore system, much of the theory and many of the practices developed for clastic reservoirs do not apply because fluid flow through cavernous, vugular, and/or fractured carbonates is fundamentally different from flow through clastic reservoirs with homogeneous pore systems. In order to understand the key geologic and engineering factors that control reservoir performance and recovery efficiency in various types of carbonate reservoirs, we have undertaken a systematic study of more than 250 carbonate reservoirs throughout the world. This paper examines 196 of these reservoirs in the fractured/karstic, conventional carbonate and organic buildup categories. Only reservoirs for which a comprehensive spectrum of parameters was available, were chosen for study. The effect on recovery of both inherent parameters and reservoir management techniques were examined, in order to achieve a thorough understanding of the relative importance of each variable. Recovery Efficiency in Carbonate Reservoirs C&C Reservoirs' DIGITAL ANALOGS System  currently contains nearly one thousand producing reservoirs worldwide. There are more than 250 carbonate reservoirs that can be analyzed and compared based on their depositional facies, diagenetic modifications, rock properties, fluid types, drive mechanisms, development strategies, EOR techniques and production histories. The advanced search engine provided in the DIGITAL ANALOGS System allowed us to easily find all of the carbonate reservoirs in the relational database and to group them into the five reservoir types defined in the abstract. Using this data, we were able to systematically evaluate genetically related reservoirs and identify the common factors that control reservoir performance and recovery efficiency in each group.