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.
The electric motor for the Gas Lift Compressor is 9.2 MW, 4-pole construction, and induction type. The motor rated voltage is 11kV, fed from 33kV switchgear via a captive 33/11.5 kV, 15 MVA transformer. A review has been performed to examine the feasibility of the gas lift compressor (GLC) motor starting with below starting methods, and to highlight advantages and disadvantages among the starting methods: - With pony motor during motor startup - Direct On Line (DOL) - With additional auto-transformer The study results indicated that the GLC motor is able to start up successfully with either type of above motor starting methods. Motor starting with pony motor is technically feasible. However, the pony motor starting method is not a common practice for induction motor, it requires additional equipment including pony motor, 415V VFD for the pony motor and MV Panel with Capacitor Bank.
The oil and gas industry is in continuous look out of innovative means to improve the efficiency of its energy-intensive oil- and gas-processing operations through improved energy use and waste-heat recovery. This paper details about an integrated pilot application of two waste-heat-recovery units designed and implemented in an Offshore platform off Caspian Sea. Actual results are compared with simulation / design results. A thermodynamic analysis of a gas generator engine waste-heat-recovery cycle is carried out.
The offshore platform has a water injection plant supporting water flooding project for reservoir pressure maintenance. The Sea Water Lift and Main Injection Pumps are powered by multiple Gas Engine Generators of @ 1000 kW power rating. The exhaust gas from each of these gas engine contains approximately 10 million Btu/hr recoverable heat. Also the heat energy from the jacket cooling water used for engine cooling is used for heating the waxy crude oil and natural gas. A Shell & Tube Heat exchanger is used for recovering the heat energy.
By utilizing the heat energy of flue gas and jacket cooling water the energy efficiency of gas engine can be doubled from 35% to 75 %. Two such Gas Generators with Heat Recovery system has been introduced which collectively creates an energy saving of approximately 1500 KW daily for crude oil heating. Approximately 8000 bbl oil with 100 scf/bbl gas oil ratio was able to heat to get a temperature differential of 25-35 degree C. The cooling water temperature was dropped to 60 degree C.
With rising fuel costs, energy conservation has taken on added significance. Installation of waste heat recovery units (WHRU's) on gas turbines is one method used in the past to reduce gas plant fuel consumption. More recently, waste heat recovery on multiple reciprocating compressor engines also has been identified as having energy conservation potential. This paper reviews the development and implementation of a WHRU potential. This enhance hydrocarbon recovery, and reduce utility cost in a plant.
In an era when energy conservation and fuel shortages are not uncommon, mechanical systems designed to improve the thermal efficiency of fuel-consuming equipment have become a necessity. This paper presents an energy efficient process and mechanical design along with footprint saving.
Designing neutral grounding systems for Generators require careful consideration of various aspects, which are mainly related to the Generators themselves and, also with respect to other aspects of the overall system design. More importantly, when the Generators to be operated in parallel have dissimilar design, the neutral grounding design must address a whole array of issues and technical requirements. While there are solutions to mitigate these issues, some of them are not appropriate for offshore installations. Introduction This paper is intended to explore in detail the various factors that influence neutral grounding design, various options available for neutral grounding and the mitigation methods for various issues associated with Generator neutral grounding. The challenges for mitigating the issues assume greater proportion when the Generators that are to operate in parallel are dissimilar in design.
It becomes evident today's Oil&Gas projects in average have higher electrical power demand than years back. In most cases technical decisions are to simply increase current to compensate power needs. Design ratings for operating and short-circuit currents of medium-voltage switchgear on generator voltage level are limiting grid design. This is the case especially for power islands. Stepping up generator voltage can be a perfect solution in particular for power grids feeding extended oil fields.
Installing step-up transformers for each generator unit and working with a network voltage up to 33 kV or higher sometimes creates disposition to believe that this is a more expensive solution.
A load-flow and short-circuit calculation for the main substation is required to properly size the switchgear and the other distribution equipment derived from planned grid arrangement and oil field process specific operation modes. It has also to be considered expected power supply quality, reliability and availability.
A cost comparison will be based on total cost of ownership between the solution with main substation on generator voltage level of 11 kV and the solutions with step-up transformers up to 22 or up to 33 kV. This comparison will also include the additional heat losses of overhead lines or cables to and between the wellpads for a year of operation.
When using higher voltages, there should be no limitation with respect to grid design and grid operation. Generally, the voltage level has to be adequate for the supply purpose. A network should be designed to avoid use of current limiters. With proper voltage level selection the bus sectionalizers can remain in NC position. It is possible that generator units are operated that loss of one set can be compensated to avoid any interruption of power supply.
Power generation can be increased when feeding via transformers to higher voltage levels of switchgear. The Power Plant Switchgear will require only a reduced short-circuit level and lower design currents for busbars and feeders to achieve optimized grid design. Unit transformers between generators and switchgear will prevent any negative influence of ground faults from the grid to the generators. Also with respect to heat losses, maintenance, grid availability and reliability as well as aging the advantages are clearly on the higher voltage level. The required power grid will be assessed based on different voltage levels. The optimized solution for the oil field will be discussed in detail.
Solution approach with higher voltage levels and optimized grid design will have reserves to deliver additional electrical power for extensions and also for operation in depletion mode.
There are now oil fields which do not allow bridging distances between wellpads by means of overhead lines but by underground cabling because of environmental conditions. Considering this aspect in cost comparison between different grid designs and voltage levels the advantage for higher voltage levels with optimized grid design will be even clearer.