Soares, P. D. (State University of Northern Rio de Janeiro) | de Oliveira, C. M. (State University of Northern Rio de Janeiro) | Morales, G. (State University of Northern Rio de Janeiro) | Arica, J. (State University of Northern Rio de Janeiro) | Matias, I. (Universidade Cândido Mendes) | Ferreira, A. S. (Fluminense Federal University) | Carneiro, V. (I-dutto)
Maintenance shutdown tasks on offshore platforms generate large revenue losses for companies in addition to high costs, partially caused by environmental adverse conditions, distances from workplaces, and large volume of materials. The use of an efficient asset controlling and monitoring system reduces these costs and improves their resource management. This work describes the development of a web/mobile architecture system integrated with radio frequency identification (RFID) transponders for asset tracking in maintenance shutdown processes on offshore platforms.
For this study development, we visited an oil and gas company, located in the city of Macaé, Rio de Janeiro, Brazil to analyze its processes. The company was facing problems on its asset management, and tracking material processes. The former takes place in two different sites. It is performed not only on-shore, but also offshore (on oil and gas platforms). Therefore, it was developed a web/mobile system integrated with RFID transponders to tackle these problems.
This system enhances efficiency in processes, reduces costs and losses because of production downtime. Its tracking is able to save up to 5.5 (five and a half) days at the laydown yard and approximately 7 (seven) days on the platform. Besides that, it ensures greater assertiveness, thus decreasing the level of materials’ replacement in the tasks, which was one of the main causes for delays in these processes. Other results are related to its managerial processes. They became automated once the RFID system integrates data in real time, and all the items from tasks defined as priorities were identified. The experimented efficiency suggests to use open source tools to reduce the system development costs, and analyze the use of RFID throughout the oil and gas supply chain, as well as studying other applications and systems in different supply chains, focusing on ways to optimize costs for the company. Additionally, it enabled the monitoring of assets and processes throughout the supply chain, besides providing information and knowledge for companies.
This paper presents the solution developed by Petrobras to support oilfield development in Campos and Santos (pre-salt) Basins. This system solution consists of a ship fitted with specialized topside and improved production string design, which together allow for quick XMT installation avoiding slickline or wireline operations, thus completely dismissing drill rigs after production or injection strings.
Well testing is a proven method for reservoir characterization, which is important for well-completion design, future development strategies, stimulation needs, and determining the commercial feasibility of the reservoir. This paper presents a surface data-acquisition system and its applications for rigless well-testing operations.
Drill-stem testing (DST), which is classified as a temporary completion of a well, typically involves a large and complex operation. A key activity during DSTs is collecting downhole pressure and temperature data using gauges at the bottom of the well that monitor pressure changes throughout the operation. Particularly crucial are the shut-in and initial build up, which provide insight into major reservoir properties. While shutting in the well at the bottom reduces the effects of wellbore storage, providing the most accurate downhole measurements, it also requires a rig and numerous personnel to prepare the well and run in hole (RIH) the test string. A rigless DST operation using a surface closure and surface data-acquisition system has been used in several wells to optimize data acquisition recovery as a non-invasive alternative to running downhole pressure gauges for pressure-transient well testing.
The effectiveness of the data-acquisition system provides advantages and accountability by avoiding the cost and risk of running equipment downhole and monitoring tests in real-time at surface.
The surface gauges acquire high-resolution pressure data at the wellhead during flowing and shut-in, which are then converted to bottomhole conditions using proprietary models. Because this technique is nonintrusive, it can be used to test wells in which downhole gauges are impractical or cost prohibitive, such as highly deviated, horizontal wells with tubing restrictions, sour-gas, high-pressure wells with high bottomhole temperatures, and low-cost evaluations. For mediumto high-permeability formations, a three-day test is typically sufficient to calculate basic near-bore and reservoir properties, including skin, permeability, and initial pressure. Longer tests that track pressure changes to reservoir boundaries can also be used to calculate the reservoir size.
The data-acquisition system has proven its efficacy after enabling a low-noise response and low-pressure changes resulting from temperature effects. Based on data provided by the data-acquisition system, the operator designed a well-testing campaign and achieved results typical of those expected using a conventional approach.
The heterogeneity of carbonate rocks results from their origin and their sensitivity to physical, chemical and biological alterations, such as dissolution, cementation and recrystallization of their minerals. These phenomena lead to pores with different shapes, origins and sizes, and, consequently, makes it difficult to predict the porosity and permeability distributions of these rocks. In addition, the high heterogeneity of carbonates affects the flow of fluids inside the reservoir and, therefore, the final oil recovery, evidencing the importance of an exhaustive petrophysical characterization of these rocks.
In the present paper carbonate rocks from the same formation were investigated, grouped into two sets: Low Permeability set (LP), with a permeability range between 5 and 15 mD; and High Permeability set (HP), with a permeability range between 90 and 150 mD. Besides basic petrophysical properties (porosity and permeability), other properties, such as pore size and pore throat size distributions, surface area, capillary pressure and relative permeability curves of each set were studied in order to correlate their properties with rock heterogeneity.
Nuclear Magnetic Resonance (NMR) was used to evaluate pore size distributions and the Mercury Intrusion Porosimetry (MICP) was used to determinate pore throat size distributions and capillary pressure curves. It was observed that HP set presents predominantly macropores and macro-throats (about 90% of the porous structure), whereas the LP set presents about 80% of macropores, but approximately the same distribution of mesoand macrothroats (from 40 to 50 %). The lack of macro-throats strangles fluids flow, and it may be one of the factors responsible for lower permeability of LP set samples. Furthermore, when the pore size and pore throat size distributions are similar, it is possible to convert the T2 distribution data to pore throat size with an acceptable correlation. Capillary pressure curves obtained by MICP were normalized with saturation data obtained by High Speed Centrifuge (HSC) tests. Initial water saturation was higher in LP set, as expected. Capillary pressure curves were compared with the data obtained by the two methods, presenting very comparable results. In the same way, the relative permeability curves also presented similar results by the two methods.
In this study we could observe the association that different permeabilities of rocks from the same formation have with petrophysical properties, such as pore size and pore throats distributions, capillary pressure and relative permeability curves.
Kimura, T. (Japan Agency for Marine-Earth Science and Technology) | Araki, E. (Japan Agency for Marine-Earth Science and Technology) | Yokobiki, T. (Japan Agency for Marine-Earth Science and Technology) | Kawaguchi, K. (Japan Agency for Marine-Earth Science and Technology) | Fujiwara, N. (NEC Networks & System Integration Co.) | Hishiki, K. (NEC Networks & System Integration Co.) | Yonezaki, Y. (NEC Networks & System Integration Co.)
We have been developing ocean bottom hybrid joint box system for real-time communication and monitoring in deep seabed. The joint box can provide high voltage power and large data transmission used in seabed as a part of seafloor cable network system. We installed first generation joint boxes in the Nankai Trough area, Japan as a part of DONET (Dense Oceanfloor Network System for Earthquake and Tsunamis)project. 12 joint boxes have been deployed in seabed with depth of up to 4000 m from 2010 to 2016. Backbone submarine cables, which provide main power and communication lines from land station to seabed joint boxes, have been deployed before the installation of the joint boxes. Each port of joint box can supply 45 Watts/port and transmit 50 Mbps data for geophysical instruments including broadband seismometer, pressure gauge (tsunami meter), thermometer, etc. 53 seafloor observation systems were connected to the joint boxes for real-time monitoring in the wide area, approximately 200 × 250 km. Observed long-term data confirmed that the joint box has high stability and reliability. There are almost no missing data except for during maintenance. We also applied a data processing method, seismic interferometry method, to long-term seismic data observed by broad-band seismometer. This method can estimate time variation of velocity structure below each seismometer by calculating auto- and cross-correlation. Obtained results confirmed that small change of seismic velocity, which would be generated by earthquake events, is detectable. Since 2014, we have developed modified joint box, which can provide high power and large data transmission, 250 Watts/port and Giga bps rate, respectively. The new joint box can transmit high density information, for example, real-time video image, and operate large seismic observation system with several hundred channels.
Multiphase measurement is still a complex process and involves an important analysis of the produced fluids in the oil industry. Intense research and technological developments in the field have been gaining important breakthroughs in the onshore sectors and especially in the offshore industry. Many companies have already developed meters that are able to read more accurately the multiphase flows and this way these developments have brought a significant number of advantages to measurement processes. The present work aims to list the important concepts that allow understanding the operation of the meters, the advantages that the multiphase measurement presents for the oil industry, including regulatory aspects for of this technology.
Nuclear Magnetic Resonance (NMR) is a powerful tool for measuring and estimating several reservoir data. This technique provides rock properties such as porosity, pore size distribution and permeability that are indispensable for accurate reservoir characterization and modeling. However, besides the importance of estimating those properties, how fast it is estimated is crucial, especially considering the large amount of money involved in the oil and gas industry. The NMR technique associated with others tools have been extensively used in standard core analysis, but despite offering reasonable results, they are very time consuming. Therefore, in order to save time and money, this article proposes an alternative and more effective core analysis workflow, so that the acquired parameters are reliable and faster measured.
A method for determining the ocean current normal to and tangentially to a seismic streamer is introduced. High resolution real time estimation of ocean currents is valuable for optimal lateral steering of seismic streamers. With optimal steering, crossflow noise caused can be reduced. Additionally, improved steering can reduce line-change times. Further, estimated ocean currents can contribute to world current oceanographic models.
A PID controller approach is used in the estimation process. The controller adjusts the ocean current normal to the streamer tangent for minimizing offsets between simulated and measured streamer positions. The streamer model is 3-dimensional and incorporates cable stretch, tension, steering devices and tailbuoy.
The current estimation method has been tested on 50 line-change data from a seismic survey. Especially on line-changes, cable steering, and hence current estimation, contribute to steering efficiency. Line-changes are time consuming, typically 3 or more hours. Efficient lateral steering could reduce this time, resulting in time and cost savings for seismic surveys. Unfortunately, steering wing angles were not available in the study data set; hence the estimation assumes zero wing angles. However, only large currents could account for the magnitude of streamer displacement relative to the zero current model result. This implies that the algorithm is capturing a significant current effect and translating it into current force quite well, as simulations given the estimated currents show good agreement with the actual streamer positions. Computational time of the algorithm is much less than real time. Hence current predictions can be made available to the streamer control system with little delay. Further, streamer prediction can be performed using the simulator with the updated ocean currents. Additionally, the estimated current can be transmitted in near real time to oceanographic research institutes.
To the authors' knowledge the present approach of current estimation has not been attempted previously. Since there exist small scale local variations in current, measuring the current only at the vessel and some stationary positions has limited value. As the current estimation algorithm can be run continuously in real time, it would provide more accurate and higher resolution information to the steering system, facilitating improved steering efficiency.
Urkedal, H. (Statoil ASA) | Selle, O. M. (Statoil ASA) | Seime, O. J. (Statoil ASA) | Brandal, Ø. (Statoil ASA) | Grøstad, T. (Statoil ASA) | Todosijevic, A. (Wintershall Holding GmbH) | Dillen, M. (Wintershall Holding GmbH) | Prasad, D. (Wintershall Holding GmbH) | Ernst, B. (Wintershall Holding GmbH) | Lehr, F. (BASF) | Mahler, E. (BASF)
A single well polymer injection and back-production test has been performed at Heidrun, an offshore oil and gas field in Norway. The objective of the test was to verify at field conditions the properties measured in the laboratory for the biopolymer Schizophyllan. This test was part of a polymer qualification program. This paper will give an overview of the single well test and lessons learned.
To ensure high quality data from the test, all elements in the test required detailed planning and following up, including an extensive quality check. The successful execution of the test was possible through a joint active collaboration between the operator, the biopolymer supplier and the service providers. The first focus was on the logistical chain from production of biopolymer, transportation and quality checking prior to injection. The second focus was on the injection, including qualifying polymer mixing equipment for offshore use and preparation for using an injector for both injection and back-production. The third focus was on sampling and analysis where high quality sampling and analysis was a prerequisite for getting conclusive results.
The test was an operational success with no HSE incidents and delivery of an extensive data set, including pressure, temperature and flowrate data as well as of fluid samples. A total of 3,500 m3 of polymer solution including biocide was injected as planned, followed by a short back-production period of 195 m3 for baseline sampling. The remaining polymer solution was shut-in for 39 days before final back-production of 365 m3. Both during injection and back-production samples were taken for later analysis and evaluation of results.
The data confirms that the biopolymer is not being biodegraded during the shut-in period due to efficient application of the biocide injected simultaneously with the biopolymer. The rate and pressure data also supports that the injectivity is maintained during the test compared to water injectivity.
Venero, Germain (Hugues Corrignan - Wood Group) | Muniz, Leandro (Hugues Corrignan - Wood Group) | Diezel, Alexandre (Hugues Corrignan - Wood Group) | Gomes, Victor (Hugues Corrignan - Wood Group) | Fachini, Rafael (Hugues Corrignan - Wood Group)
This paper presents the procedure for the calibration of a soil model represented by P-Y curves in the global finite element model of a drilling riser system using onboard measured data.
In the case of lack of real data or data uncertainty regarding the soil properties of one specific well location, the soil model can be calibrated using measured data during the drilling campaign.
The calibration procedure improves the accuracy on the prediction of the wellhead bending moment and stresses along the conductor pipe based on global riser analyses performed during the operation to assure the integrity of the well structure and thus, safe operations.