The goal of this paper is to present the philosophies for the qualification and flow loop testing of FCD nozzles as well as the macroscopic implementation and operations of FCDs in SAGD producer wells. A quantitative methodology to evaluate FCD nozzles to choke back steam will be presented. Flow loop testing data will be shown to illustrate the qualification process. We will also discuss if sand control screens should be put on the tubing deployed inflow control devices. Some modeling and field examples will be shown. In the end, field data of the SAGD producer wells installed with the FCDs will be presented. Experience to manage and operate the wells will be shared.
Li, Jiankuan (University of Alberta) | Sun, Chong (University of Alberta) | Roostaei, Morteza (RGL Reservoir Management Inc.) | Mahmoudi, Mahdi (RGL Reservoir Management Inc.) | Fattahpour, Vahidoddin (RGL Reservoir Management Inc.) | Zeng, Hongbo (University of Alberta) | Luo, Jing-Li (University of Alberta)
This study presents an investigation of the on-site corrosion of carbon steel pipes with stainless steel mesh screens in a steam flood well in the Athabasca oil sand reservoirs to determine the failure patterns and mechanisms. To mitigate the corrosion of carbon steel, several candidate materials were selected, and their corrosion resistance was investigated. In this work, the corrosion behavior and film characteristics of carbon steel pipes were studied by surface analysis techniques such as scanning electron microscopy, energy dispersive spetrocsopy and X-ray diffraction. Corrosion resistant alloys (proRSf and proRSc), anti-corrosion coating (proRA05a) and pretreated steel (proRAQa) were considered as alternative materials to carbon steel (proRAa and proRAb) and their corrosion protection performance in brine solution was evaluated by electrochemical methods such as potentiodynamic sweep and electrochemical impedance spectroscopy. Results show that severe erosion-corrosion occurred on inner wall of the pipes and caused significant wall-thinning of pipes along with localized corrosion damages, which is the dominant reason for base pipe failure. In spite of the slight corrosion on outer wall of the base pipe, severe localized corrosion appeared at the interface between the carbon steel pipe and stainless steel mesh screens due to the galvanic corrosion effect of dissimilar metals. The corrosion rates of the corrosion-resistant materials were two or three orders of magnitude lower than that of carbon steel.
The corrosion of carbon steel tubing, pipelines and process equipment during Oil and Gas production due to salt water saturated by corrosives gases, such as carbon dioxide and hydrogen sulphide, can lead to substantial environmental and economic consequences. A lot of different technics are used to reduce the corrosion in the pipelines: use of specific alloys, biocides or H2S scavenger. One of the proven and most widely used mitigation techniques is the addition of film-forming corrosion inhibitors into production streams. Those compounds have affinity with metals and will thus form a film at the surface of the metal, creating an electric resistance between the metal and the corrosive species. The products used offshore and released in the North Sea are currently controlled by OSPAR Convention requiring to meet environmental criteria on three different parameters: Biodegradability, Toxicity and Bioaccumulation. Passing 2 out of 3 criteria is enough to comply with the OSPAR Convention. This paper presents the performance results obtained with novel biodegradable compositions used as corrosion inhibitors for continuous injection with a thermal stability up to 135 C. A superior performance against sweet corrosion was obtained at 80 C in brines of different salinity, both in the presence and absence of a hydrocarbon phase. Additionally, new compositions exhibit low critical micelle concentrations and their structure can be further modified to adapt to various salinity conditions.
Equilibrium Pc-RI measurements on low permeability core plugs present the SCAL laboratory with some difficult challenges regarding the duration of measurements and the attainment of truly equilibrated resistance readings. A new empirical method is described that allows estimation of fully equilibrated resistance by application of a simple transient data linearizing transform and plot slope analysis. A small set of plugs from a conventional tight gas field in the Sultanate of Oman is used to demonstrate the method. The method may also be used by the lab to monitor and shorten the Pc-RI measurement duration without compromising the interpretation of saturation exponents or capillary curves. Transform plot transients and macro capillary number are examined to estimate a boundary where the plugs transition from shock front rapid desaturation to slow percolation desaturation behavior.
Repetto, Carmen (Eni) | Gorini, Simone (Eni) | Nutricato, Giacomo Andrea (Eni) | Torri, Lucia (Eni) | Cavassi, Paolo (Eni) | Zucchetto, Maria Ornella (Eni) | Guglielmo, Carmelo (Eni) | Gravante, Elpidio (Eni) | McIntosh, Neil (Maxtube Limited) | Balistrieri, Roberto (Mepeco)
The composite liner is made of a Glassfibre Reinforced Epoxy (GRE) resin, inserted in Carbon Steel tubing and it can be used in both production and water injection wells.
Different laboratory tests performed either by manufacturers and by operators, have been carried out in order to confirm and verify the material characteristics and reliability.
In particular, Eni in 2009 tested GRE in sour environment with CO2 and H2S to investigate the capability and service limits of the resin liner at different temperatures.
According to the positive results of the tests, Eni has firstly applied GRE in 2005 in Tunisia where it was successful in reducing onshore workover costs and extending the life of Carbon Steel tubing in oil producer wells with high CO2 and water cut.
The latest application was in Norway where it has been installed on water injector offshore wells, where, due to high corrosiveness of the injection fluid (raw seawater with antifouling chlorination), the liner was selected as cost effective alternative to high alloyed materials.
More recently, Eni was involved in particularly challenging deepwater development projects with highly productive gas wells in sour and harsh environment.
Typically, these applications require high grade Corrosion Resistant Alloys (CRA) production tubing with an important impact on the completion costs and operative run in hole issues. Following the positive experiences gained in the last 15 years in the application of glassfibre liner, it was evaluated the possibility to deploy the material as a corrosion barrier in well production tubings under more critical conditions.
Eni decided to perform some additional laboratory tests in collaboration with Milan Polytechnic. Direct impact test and straight pipe test were performed in order to characterize the erosion behaviour of GRE composite material, supplied by two different manufacturers, and simulating the case of wells with high erosion rate risk.
The results demonstrated GRE to have a good resistance to the solid particles erosion in comparison to very similar tests on Inconel Nickel Alloy material and confirmed the potential use of GRE as a corrosion resistance material when combined with Carbon Steel tubulars as an alternative to the usual high CRA materials in producer wells.
This paper will present the characteristics of the technology, the laboratory tests performed with their results and the acceptable range of field conditions.
Additionally, the paper will provide Eni field experiences, including feedback, lessons learned and economic evaluations.
Yang, Hongbin (China University of Petroleum, East China) | Kang, Wanli (China University of Petroleum, East China) | Zhang, Hongwen (China University of Petroleum, East China) | Zhou, Bobo (China University of Petroleum, East China) | Li, Xinxin (China University of Petroleum, East China) | Wang, Fang (China University of Petroleum, East China)
Profile control treatment is an effective technology to improve reservoir heterogeneity and decrease the watercut. Polymer gel has become the most widely used profile control agent. The most commonly used polymer in polymer gels is HPAM, which has poor adaptability in high temperature and high salinity reservoirs resulting in poor gel performance. Amphiphilic polymers have good viscosifying action in high temperature and high salinity reservoirs due to the polymer chain entanglement and hydrophobic chain association. In this paper, one amphiphilic polymer (PADC) was developed by introducing a betaine type functional monomer. In order to further improve the anti-temperature performance of PADC, the idea of using inorganic nanoparticles for enhancement was proposed. Based on this, a composite gel with good temperature and salt resistance was developed by adding crosslinking agent. The effects of nanosilica particle concentration, polymer concentration and crosslinking agent concentration on the gel performance of the composite gel were investigated systematically. The results showed that salt viscosifying action ability was related to the ionic strength. The higher the ionic strength, the larger the polymer molecular hydraulics radius. At the same time, the strength of hydrophobic association was improved and formed a denser spatial network structure. The synergistic effects made PADC have the characteristic of salt viscosifying action. It was also found that the viscoelasticity of the polymer solution changed from a viscous system to an elastic system by adding nano-silica, and apparent viscosity increased significantly. We have demonstrated that nano-silica surface will adsorb free polymer moleculesin solution, and form molecular brushes due to charge attraction and hydrogen bonding. The molecular brushes will adsorb and combine with the spatial network structure formed by the amphiphilic polymer. A significant improvement in the gel strength of composite polymer gel compared with organic polymer gel. Our work indicates that the composite gel based on amphiphilic polymer has significantly potential applications in high temperature and high salinity reservoirs, it has certain reference significance for stabilizing oil output and controlling water content for the similar reservoirs.
A jacket structure is designed to support a platform required for drilling and production facilities. The jacket is subjected to complex, multi-directional loading during installation. Overturning moments from wind, current and wave loads are skewed from overturning moments from pile and jacket weight eccentricity. The mudmat geometry can be simple with symmetrical mudmats at the four corners of the jacket base or can be complex due to full rectangular area with an off-center, open, rectangular bay for conductor installation. Mudmat geometry, loads during pile installation and soil conditions combined to produce a challenging overturning stability problem. Equivalent area methods of API RP 2GEO and ISO 19901-4 may not predict the low overturning resistance, and a typical righting moment analysis may not capture the soil-structure interaction. To address the geometry and complex loading, a plasticity analysis of overturning stability was performed and is described herein.
Partial safety factors as recommended by API RP 2GEO, ISO 19901-4 were used to assess stability so that overturning from the jacket dead weight could be treated separately from the wind, current and wave loading. Since the partial safety factors are lower for the stabilizing forces compared to the forces causing overturning moments, the resulting safety factors can be lower. Moment and force equilibrium were imposed, and the minimum overturning safety factor was found. Although the vector sum of the factored loads was oriented away from a principal axis of the mudmat, upper bound plasticity methods were used to investigate kinematically admissible failure mechanisms. The method of analysis easily accounts for irregular foundation geometry and complex, multidirectional loading with varying degrees of uncertainty. The method fills a gap in API RP 2GEO and can be implemented in a simple spreadsheet.
A case study is presented to demonstrate the safety factor variation using API RP 2GEO method and the proposed failure method with varying eccentricity in the gravity loads and overturning moments due to wind, current and wave loads.
Traditional internal coating systems relied on phenolic, novolac, epoxy or blended resin systems. These tended to provide good barrier properties in the environments they were developed for, but as with all materials, there were limitations. One of those limitations that had to be overcome during the development and application process was that during the curing process, they can tend to shrink, so greater surface preparation processes must be followed to ensure that the system adhesion far outweighs the residual stress in the coating system. In sweet applications, this residual stress offers little to no effect on a properly applied coating system provided its design parameters are not exceeded. In the presence of higher concentrations of hydrogen sulfide, there can be a negative effect on the adhesion of most of these resin type coating systems allowing the residual stress to play a role in blistering and disbondment. A new and novel resin system has been developed that does not shrink during the curing process and can be applied as a primer-less system. Coatings developed with this new resin, benzoxazine, allows the coating system to maintain good adhesion and barrier properties in H2S concentrations two to three times greater than the current leading H2S resistant coating systems on the market today. This paper will outline the technology behind this new resin system as well as the overall properties of the coating being delivered to market.
Ke, Xu (Research Institute of Petroleum E&D(RIPED), PetroChina) | Yongjun, Lu (Research Institute of Petroleum E&D(RIPED), PetroChina) | Xin, Wang (Research Institute of Petroleum E&D(RIPED), PetroChina) | Yang, Shi (Research Institute of Petroleum E&D(RIPED), PetroChina) | Minje, Xu (Research Institute of Petroleum E&D(RIPED), PetroChina) | Xiaohui, Qiu (Research Institute of Petroleum E&D(RIPED), PetroChina)
The early shale gas mining in North America mainly used linear adhesive fracturing fluid, and later, with the deepening of the research and the requirements of component control, the slippery water fracturing fluid system was gradually used. Because of its low viscosity, slippery water can easily communicate micro-cracks and layered seams at different scales, forming a complex volume of network cracks.
Hydraulic fracturing technology has been widely used in oil and gas industry to increase production since 1947. Linear and crosslinked guars are the most commonly used fracturing fluid system. Concerns over damage to conductivity caused by viscous fluids in unconventional reservoirs, the industry has developed an alternative fracturing fluid called slickwater, which consists mainly of water and the low concentration of linear polymer. Slickwater has the characteristic of poor sand carrying capacity, and it is necessary to develop a smart slickwater to improve sand carrying capacity.
The paper introduces a new smart slickwater with high proppant- carrying capability for shale reservoirs. The fluid system consists of linear self-assembled agent, which can improve the viscosity of slickwater at low concentration and maintain a high drag reduction rate. The advantage of the smart slickwater is that only one chemical additive is used, and when the concentration is 0.05%, the drag reduction rate can reach more than 75%, and when the concentration is 0.2%, the proppant ratio can reach 30%, replacing the linear and crosslinked guars.
Laboratory experiments were conducted using the smart slickwater to display excellent static and dynamic sand carrying capacity. The smart slickwater is used in Changqing Oilfield(China), compared with the traditional slickwater, the product is less expensive to use, less water for fracturing, less types and dosage of chemicals required, less equipment needed.
The new smart slickwater with high proppant- carrying capability can change the existing structure of fracturing fluid system.
Ju, Xuanze (COOEC Engineering Company Middle East Branch) | Liu, Zhigang (COOEC Engineering Company Middle East Branch) | Shi, Lei (COOEC Engineering Company) | Li, Gang (COOEC Engineering Company) | Xing, Guangkuo (COOEC Engineering Company)
Subsea manifold is a flow-routing subsea hardware (subsea flow router) that connects between subsea trees and flowlines. It is used to optimize the subsea layout arrangement and reduce the quantity of risers connected to the platform, the new engineering technology of subsea manifold to be studied in this paper. From the perspectives of safety, economy, constructability, installation, operability and maintainability, it is proposed to divide the subsea manifold into three parts: manifold module, protection structure module and foundation module, thus forms the new split-type subsea manifold engineering. On the basis of analyzing the functional requirements of subsea manifolds, the method of manifold design and piping stress check is given herein. The protection structure design mainly involves protection against dropped object impact, fishing nets and dropped object. The structure design and strength checking method of dropped objects impact and trawl-board impact are also given. There are mainly two types of foundation for subsea facilities: mudmat and suction pile. Mudmat is more cost effective, hence it is the preferred solution. The design calculation method of mudmat is given (including vertical bearing capacity, torsional resistance, sliding resistance, overturning resistance, settlement calculation, skirt penetration capacity). Finally, the three modules are combined to form a new split-type subsea manifold design, which has been successfully implemented in South China Sea, providing a reference for the application of the new split-type subsea manifold.