The electrical system of a typical oil field consists of power generation, power distribution, electric motors, system protection, and electrical grounding. The power is either generated on site or purchased from a local utility company. Various organizations in the U.S. and other countries have developed many electrical codes and standards that are accepted by industry and governmental bodies throughout the world. These codes and standards provide guidelines or rules for design and installation of electrical systems. Also, U.S. regulatory agencies have established some requirements for the design, installation, and operation of offshore production platforms.
The required power for the oil field is either generated on site by engine- or turbine-driven generator sets or purchased from a local utility company. The engines or turbines may use diesel or natural gas as a fuel. Some units are dual-fueled, using natural gas and diesel. Natural-gas-fueled prime movers are most practical for normal power generation for most applications. Diesel is used where natural gas is unavailable and for units that provide black-start and emergency power.
One of the options for gas monetization is gas to power (GTP), sometimes called gas to wire (GTW). Electric power can be an intermediate product, such as in the case of mineral refining in which electricity is used to refine bauxite into aluminum; or it can be an end product that is distributed into a large utility power grid. This page focuses on electricity as the end product. The primary issues related to GTP are the relative positions of the resource and the end market and transmission methods. The scale or volume of gas and/or power to be transported influences each of these issues.
Treatment evaluation leads to problem identification and to continuously improved treatments. The prime source of information on which to build an evaluation are the acid treatment report and the pressure and rate data during injection and falloff. Proper execution, quality control, and record keeping are prerequisites to the task of accurate evaluation. Evaluation of unsatisfactory treatments is essential to recommending changes in chemicals and/or treating techniques and procedures that will provide the best treatment for acidizing wells in the future. The most important measure of the treatment is the productivity of the well after treatment.
Zhang, Tuanfeng (Schlumberger-Doll Research) | Tilke, Peter (Schlumberger-Doll Research) | Dupont, Emilien (Schlumberger-Doll Research) | Zhu, Lingchen (Schlumberger-Doll Research) | Liang, Lin (Schlumberger-Doll Research) | Bailey, William (Schlumberger-Doll Research)
This paper proposes a novel approach for generating 3-dimensional complex geological facies models based on deep generative models. It can reproduce a wide range of conceptual geological models while possessing the flexibility necessary to honor constraints such as well data. Compared with existing geostatistics-based modeling methods, our approach produces realistic subsurface facies architecture in 3D using a state-of-the-art deep learning method called Generative Adversarial Networks (GANs). GANs couple a generator with a discriminator and each uses a deep Convolutional Neural Network (CNN). The networks are trained in an adversarial manner until the generator can create "fake" images that the discriminator cannot distinguish from "real" images. We extend the original GAN approach to 3D geological modeling at the reservoir scale. The GANs are trained using a library of 3D facies models. Once the GANs have been trained, they can generate a variety of geologically realistic facies models constrained by well data interpretations. This geomodelling approach using GANs has been tested on models of both complex fluvial depositional systems and carbonate reservoirs that exhibit progradational and aggradational trends. The results demonstrate that this deep learning-driven modeling approach can capture more realistic facies architectures and associations than existing geostatistical modeling methods, which often fail to reproduce heterogeneous nonstationary sedimentary facies with apparent depositional trend.
Liu, Yigang (CNOOC China Ltd, Tianjin Branch) | Zou, Jian (CNOOC China Ltd, Tianjin Branch) | Han, Xiaodong (CNOOC China Ltd, Tianjin Branch) | Wang, Qiuxia (CNOOC China Ltd, Tianjin Branch) | Zhang, Hua (CNOOC China Ltd, Tianjin Branch) | Liu, Hao (CNOOC China Ltd, Tianjin Branch) | Wang, Hongyu (CNOOC China Ltd, Tianjin Branch) | Wu, Wenwei (China University of Petroleum, Beijing) | Wang, Cheng (China University of Petroleum, Beijing)
Steam and flue gas stimulation technology has been applied for heavy oil exploitation in Bohai Oilfield for almost ten years. For the special fuel and water requirement of the current thermal generator, large amount of diesel and desalinated seawater are needed during the thermal injection process. Besides, treatment of the produced oily wastewater on the platform becomes more difficult as the oil output increases.
Aimed at solving the existing problems and taking the advantage of characteristics of the supercritical water, a new type of supercritical steam and flue gas generator for offshore oilfield is proposed and studied. The newly proposed generator is mainly consisted of two sections, which are the supercritical water gasification reactor and combustion reactor, respectively. The produced oily wastewater could be directly used for steam generation. A series of experiments are carried out for its feasibility research and structure optimization.
A prototype of the generator is made for indoor experiment. During the gasification process, wastewater and the organic material mixed inside is placed in the supercritical conditions in the gasification reactor whose temperature and pressure are about 600-700°C and 23MPa, respectively. And the reaction product would be mainly H2, CO2 and water. Gasification Experiments of both the diesel and oily wastewater are conducted. And the combustion experiment is also conducted and the gasified gas is reacted with O2 under conditions of 25MPa and 500-550°C. Composition of the produced fluid in each experiments are analyzed. Besides, the structure of the generator is also designed and optimized for improving its working efficiency.
The proposed new-type supercritical steam and flue gas generator has the characteristics of high efficiency, waste water treatment and higher temperature and pressure delivery capacity. And there would be a promising perspective for its application on offshore platform.
High levels of drag, especially in horizontal and extended-reach operations, can be a major concern during sliding or rotating. Drag reduces drilling efficiency by requiring increased energy input, primarily through increasing torque and weight on bit, to achieve the desired rate of penetration (ROP). Reduced drilling efficiency results in excessive tool wear, lower ROP, and poor directional control. Of the several methods the industry uses to combat drag, the scope of this study was focused on the use of a pulse generator paired with a displacement generator, which makes up a drilling agitator tool (DAT). A DAT is commonly used in extended lateral formations to improve weight transfer to the bit in vertical and nonvertical drilling applications. The operational principal of the DAT is the production of a pressure pulse that causes a repetitive axial motion in a shock tool. This paper compares offset run data between two DAT cases—one run with a traditional DAT and the other on a new, efficient, "high-energy" DAT (HE DAT). The run performance in similar portions of vertical and horizontal sections was compared between the two systems.
This study was based on data collected from a pressure pulse and axial displacement data recorder from horizontal wells in the STACK play drilled by Devon Energy. The objective of this study was to observe the performance of the HE DAT and determine if there was a noticeable gain in performance in terms of drilling efficiency and ROP as compared to a standard DAT. These results are discussed in detail and supported by high-resolution data collected during drilling.
The data analysis presented here provides an in-depth look into the operation of the HE DAT's performance as compared to the standard DAT in a very similar offset well. Overall, a 20 to 25% increase in ROP with the HE DAT was expected, effectively validating the enhancements made to the tool. This study collected data using data recorders—novel, small, self-contained devices measuring axial vibration, internal pressure, temperature, and axial displacement—located directly above and below the DATs to make a comparative assessment and deliver information about drilling data that was otherwise not available via conventional downhole measurement tools.
The porosity response of four proposed generator-based neutron tool concepts is studied using Monte Carlo simulation of the radiation transport. The objective is to examine, at a fundamental level, the potential of these sources to replace americium-beryllium (Am-Be) sources primarily in openhole applications and, briefly, in a through-casing application of interest to a number of operators. The accelerator-based sources include a dense-plasma focus (DPF) alpha-particle accelerator and deuterium-tritium (DT), deuterium-deuterium (D-D), and deuterium-lithium (D-7Li) neutron generators. The DPF uses the (a-Be) reaction to generate a neutron spectrum that is nearly identical to that from an Am-Be source. D-T and D-D neutron generators use compact linear accelerators and produce, respectively, 14.1 and 2.45 MeV neutrons. The D-7Li neutron spectrum resembles the Am-Be spectrum at lower energies, and has a neutron peak at 13.3 MeV
Simple spherical-geometry models that do not include tool and borehole are used to explore the basic physics. An openhole tool-borehole-formation configuration is used to explore key observations from the simpler model. In both models, the responses at various detectors are examined to understand the behavior of the ratios constructed. Sensitivity to formation conditions, such as lithology, presence of gas, low porosity and presence of thermal absorbers, and operational conditions, such as tool standoff, are examined. A casedhole configuration is also analyzed where neutron counts are the only method for zonal correlation.
The state of neutron-generator technology is discussed in terms of neutron yield, target properties, power demands etc., which are important considerations for implementing such generators in nuclear logging tools.
This paper addresses the need and challenges associated with the energy harvesting methods in the downhole multilateral openhole horizontal well environment. The need for downhole energy harvesting is discussed and the functional requirements are established. Different means of energy harvesting that are available in either or both flowing and shut-in conditions are presented and the possibility of using them in the downhole horizontal wells for long-term monitoring and control systems is evaluated.
Variable Frequency Drives (VFDs) are employed in the heavy industry like oil rigs, refineries and mills etc., as they result in efficient plant operation. However, with the increased penetration of VFDs, the power quality problems have become significant. The focus in this thesis s is to study the power quality problem in the oil rigs of ADNOC Drilling. ADNOC Drilling has different types of variable speed drives in their on shore and off shore rigs. The purpose of this study is to collect field data, check the harmonic distortion and suggest other suitable solutions to improve the power quality in offshore oil rigs. Most of the old rigs are set up in 1970s and they use variable speed DC drives. The new offshore rigs use VFDs. Some these new rigs are equipped with series inductors in VFDs. Generator voltage distortion, overheating of generators, poor power factor, unwanted tripping are the common problem faced by these rigs.
This thesis investigates the harmonic problems in VFDs, reduction in harmonic due to the usage of series inductance. Detailed investigation is carried out to check if the series inductance is able to reduce the harmonics to acceptable levels or not. The typical oil rig power system simulated using ETAP and necessary harmonic distortion data generated from MATLAB. It is observed that series inductor will keep the THD within acceptable limits if the generator is oversized. For better utilization of generators and harmonic mitigation other alternative solutions such as tuned passive filters are required. This study is significant for oil rigs and other industries as it will help the industry in studying the harmonic problems and mitigation techniques. The suggested solutions will help the industry in better utilization of generator and efficient operation of the plant.