Ivaschenko, D. (RN-UfaNIPIneft LLC) | Davletbaev, A. (RN-UfaNIPIneft LLC) | Baikov, V. (RN-UfaNIPIneft LLC) | Bulatov, I. (RN-UfaNIPIneft LLC) | Seidl, G. (Montanuniversität Leoben) | Simon, E. (RN-Purneftegaz LLC)
The pdf file of this paper is in Russian. To purchase the paper in English, order SPE-166909-MS.
Gas well testing (GWT) is one of the principal methods for estimating its flow potential and to determine reservoir properties and bottom-hole area conditions. Further, it allows to make use of non-linear filtration influence. Reliability of GWT results is important for the choice of field development strategy and production stimulation.
The paper focuses on non-linear filtration research, but unlike to well-known purely theoretical results, we developed a set of guidelines designed to conveniently process and interpret field data. We state that modern mathematical methods such as wavelet analysis and accurate planning of field experiments are key in order to acquire more reliable information about reservoir and well properties. This approach can further be applied to lay out the Arctic shelf gas reservoir engineering and planning the well intervention techniques.
The pdf file of this paper is in Russian. To purchase the paper in English, order SPE-168659-MS.
Over the last years there is a great progress in the dynamic simulation approach to wellbore processes modeling. First of all, it is explained by the reason that classic modeling method (nodal analysis) is unable to take into account every wellbore transient processes completely. The processes, in their turn, constitute an integral part of the well performance during the start-ups - shutdowns, changes of well operation mode.
The main objective of this study is to develop qualitative and quantitative understanding of well transient processes and opportunity to optimize the well operation as well. This problem is important today because there is no reliable instrument enabling to estimate and optimize well operation under the transient processes.
Well bore and reservoir modeling methods
Classical method for multiphase flow in pipes (or well bore) is static correlations. This is rather simple and not a lot of CPU time consumption approach. However there are some problems which demand transient conditions. In this case the only method is to use dynamic simulation. Computer developing in our days gives us possibility to solve such problems.
For this study special "OLGA?? software ("SPT Group??) is used. It takes into account:
- three-phase flow;
- unsteady flow regime;
- impact of surface and subsurface equipment;
- comprehensive fluid model;
- impact of the heat losses in the well and detailed well construction;
More detailed information can be found in references section.
After choosing well bore simulator the issue about reservoir modeling is appeared. The simplest method is to use inflow performance relationships (IPR). But there is a strong limitation due to impossibility to take into account transient process near the well bore in this case. This is fully static method.
That's why "ROCX?? software was chosen. "ROCX?? is the simplified near-well zone simulator - is used for the reservoir modeling. This simulator allows for a transitivity nature of the well-reservoir interference. It uses input parameters, such as porosity-permeability, PVT model, relative permeability, boundary and initial conditions.
Tskhadaya, Nikolay D. (Ukhta State Technical University) | Buslaev, George V. (Ukhta State Technical University) | Buslaeva, Olga N. (Ukhta State Technical University) | Molokanov, Denis R. (Ukhta State Technical University)
The article offers scientific solutions regarding drilling of horizontal extended reach wells for the Arctic development. In particular, ground-based drilling complex of XXI century with tipping tower was developed. The article describes constructions of its overland and borehole components. A lot of attention is paid to load transfer from the well head to its bottomhole. The article describes solutions made for addressing problems connected to additional loads on the bottomhole and well head; in particular, even drilling bit feed need. The article also includes calculation of the well profile and load characteristics of the drilling complex for the well of 15 km and horizontal borehole depth of 1.5 km. The author proves perspectives of field's application and data about testing of downhole drilling thrusting device; offers a horizontal borehole subsea depth estimating method, according to fracturing prevention and sea bed pollution. The article shows a mathematical model of heat and weight transfer in the well for foundation of managerial parameters of formation exposing, drilling and casing in permafrost.
A Steamflooding study has been doing to extract the bitumen and improve oil recovery in a heterogeneous light oil reservoir of South Rumaila oil field. It has been investigated also that Steamflooding is an effective way to handle the formation's heterogeneity by decrease the degree of fluid spread and distortion. It has been considered the design of experiments methodology and streamlines-based simulation to study the most sensitive factors affecting the cumulative oil production response and also to determine the optimal future reservoir performance. This paper is an extension work of the papers (SPE 165345 & SPE 165935) to evaluate the Geomechanical deformation associated with the production processes through steamflooding and water injection scenarios. The reservoir under study is a sandstone formation in South Rumaila oil field located in Iraq. This field, with a 59-year production history, has 40 production wells and is surrounded by an infinite active edge water aquifer from the east and the west flanks. Because of some discontinuous series of bitumen at the east flank, the strength of east flank is much effective less than the west one. In this study, a comparative thermodynamic simulation study has been conducted to show the feasibility of Steamflooding to extract the bitumen and improve oil recovery and to determine the optimal future development scenario in addition to locally estimating the associated reservoir deformation due to steamflooding processes and the base case of water injection.
In this paper, the black oil & thermodynamic reservoir simulator have been used to evaluate the reservoir performance through the base case and steamflooding scenarios, respectively. Later, full factorial design and streamlines-based simulation have been conducted to figure out the most factors affecting the response (recovery factor) through Steamflooding with distinct levels. The factors are steam injection rate, quality, temperature, and number of steam injectors.
SuperSonic gas Separation technology (3S-technology) was designed to prepare the gas for transportation and to extract different fractions from gas, such as hydrocarbon condensate, propane-butane and ethane. The technology is based on cooling of swirling gas in supersonic Laval nozzle. Due to the implementation of high speed in the nozzle, the temperature of gas can be reduced by 70°C and more, thus ensure conditions needed for condensation and separation of heavy fractions contained in gas. A device, realizes this process, is called "3S-separator??. It comprises a stationary swirl body, a supersonic nozzle and a diffuser with selection of condensed fluid.
It has been proved that usage of 3S-separators instead of Joule-Thomson valves makes it possible to ensure higher operating efficiency of associated gas processing devices in any parameters. And it can reduce dew points of water and hydrocarbons of a tank gas and increase the amount of gas recoverable from unstable condensate.
3S-separators make it possible to extract target components from natural gas in wide gas input pressure range from 1.0 MPa to 16 MPa. To ensure the optimum gas temperature at 3S-separators inlet recuperative heat exchangers should be used.
At present 3S-technology is successfully used by several industrial plants in Russia ("Rosneft" JSC, "Gazprom" JSC) and abroad (PetroChina Company Ltd.). The use of this technology in subsea processing plants will enable to carry out gas conditioning in accord with sales gas qualifying standards. Thus, as opposed to currently existing gas cooling technologies, based on using of expansion turbines and refrigerator sets, 3S-technology makes it possible to ensure high equipment reliability and enables to install equipment on the seabed. The more promising area - is use of 3S-technology in projects of getting a high pressure (100 and more atmospheres) sales gas. It is impossible to use conventional gas cooling technologies, because of supercritical conditions of natural gas, under which gas additives condensation is not possible at any temperatures. By ensuring high-speed gas flows in supersonic nozzles, there could be a condensation and separation of natural gas target fractions in 3S-separators, even in a high gas pressure conditions.
The pdf file of this paper is in Russian. To purchase the paper in English, order SPE-166870-MS.
A method and an apparatus for killing of uncontrolled oil fountains include a series of rods with the first rod having the smallest diameter and successive rods having increasing diameters. Such telescopic assembly of rods is lowered into the well to cause gradual reduction in cross-sectional area available for oil flow discharge. Once sufficiently large rods are lowered into the well, the oil fountain discharge will be greatly diminished. A method of monitoring the conditions of lowering the rods into the well may utilize a weight measuring device mounted at the surface platform. In the case of killing the oil fountain based on the present method, such device will show the difference between the weight of the rods (pushing the entire assembly down) and the combination of various forces acting to push it up, including the reservoir pressure and the drag force from the flow of oil or a multiphase flow of various gases and fluids coming out from the well. Final sealing may be accomplished by pumping cement into a space formed between the well pipe and the rod assembly. A novel system for aligning the rods to the center of the well is also described. The present method is aimed at making killing of the well safe, fast and inexpensive so as to prevent heavy environmental and financial losses typically associated with dealing with offshore well blowouts.
The pdf file of this paper is in Russian. To purchase the paper in English, order SPE-166824-MS.
The Alaska North Slope, within the Arctic Circle, is a challenging environment to operate seismic crews. The company has operated land and marine seismic programs on the North Slope since 1979. We present a review of the summer 2012 Simpson Lagoon seismic survey, outlining the safety, operational and technical challenges faced in an arctic transition zone environment. Ocean Bottom Seismic (OBS) data on the North Slope is essential for the effective development of the hydrocarbon fields, providing improved and accurate subsurface imaging. The arctic open-water season provides a short window of opportunity to collect OBS data, bounded by the seasonal break-up and freeze-up of the sea ice and subsistence whale hunting. These factors constrain the quantity and influence the quality of the data collected, however sufficient resource allocated to pre-season planning is critical to the success of the seismic project. We demonstrate the planning and decisions made were influenced by the safety of the seismic crew, minimizing impact to the environment, and the collection of quality seamless subsurface seismic data. Key successes of the survey include: 24 hour operations completed within 45 days; completion of the seismic objectives equating to 88 square miles of data; enhanced imaging below the lagoon barrier islands carried out by safe and efficient helicopter operations utilizing autonomous land nodes; and innovative techniques for burying receiver sensors into the surf zone which significantly improved data quality.
CJSC "Rospan International", a subsidiary of OAO "NK" Rosneft ", is currently engaged in the preparation for full-scale development of oil fields in Yamal and the north of the Krasnoyarsk Territory.
One of these fields - Tagulskoye, located in the north of the Krasnoyarsk Territory. Infrastructure and road network in the area of the field is absent. Transportation of goods is carried out on the winter road in the summer - water and helicopter transport. Developed by the near field - Vankorskoye, located 45 km to the north.
Active research field began in 2009 with the implementation of the pilot area number 1 (section pilot development). In 2009-2010, drilled five wells, including four with horizontal shaft. Conducted in 2010-2013 set of studies aimed at reducing the geological, technological risks, optimize system design to improve the reliability of the forecast of technical and economic indicators.
The article summarizes the main results of pilot projects, analyze their performance. A comparison of predicted and actual characteristics of reservoirs, mining potential wells. The approach to preparing the fields to infrastructure constraints.
The aim of this paper is to review the challenges of onshore and offshore welding operations in Arctic extreme environments in terms of:
It lists the key elements to ensure successful onshore and offshore welding operations meeting both project productivity and quality targets in extreme cold areas.
Qualification of equipments either in cold chamber or in extreme cold conditions is a pre-requisite. It must be ensured that batteries, materials (metallic and non metallic), fluids (hydraulic and engine oils …) are suitable for the working conditions. Due to logistics issues, preventive maintenance on all equipments is very important before starting any operation.
Work organization is highly impacted by workers exposure to very low temperature. High performance protective clothes are helpful but harsh external conditions mainly promote the use of automated, reliable and high deposition rate welding processes.
Finally, welding quality is a major concern to avoid pipeline leak or failure in very sensitive environments with difficult access for emergency repairs. It relies on qualified welding procedures, a limited number of manual operations, narrow ranges of welding heat inputs, strictly controlled preheating conditions and real-time monitoring of welding parameters during operations.
The main contributions of this paper are: