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SPE Member Abstract This paper presents a concept for diverting and controlling a subsea blowout to prevent major pollution in shallow or deepwater ocean areas. The pollution in shallow or deepwater ocean areas. The concept has been developed, model tested, and several of the concept components have been utilized in the field. Several blowouts have occurred which have resulted in oil and/or gas flowing from a subsea well or BOP. The flow, when it reaches the ocean surface, must be collected. The concept reported in this paper diverts the subsea well flow to a collection vessel before the flow reaches the surface. A funnel with riser suspended from a barge is positioned over the subsea well. The well flow, which contains gas, lightens the fluid column inside the riser and the well fluids flow up through the riser to the collection barge. Once the well flow is diverted, a method of entering and stopping the well flow from the well bore is available via the funnel and riser. This complete system, the model tests, the field application, and the future use of the diverting and controlling procedures are reported in this paper. General This paper presents new technology in diverting and controlling offshore subsea blowouts. Offshore floating drilling increased by more than 500% between 1960 and 1984. In comparison with the wells drilled in 1960, the wells drilled in 1984 were drilled in more severe environments, they were deeper, in deeper water, and in areas where less is known of subsurface conditions. Exploration drilling in areas where minimum data is available on subsurface pressure has been increasing. The equipment and trained personnel the industry has drilling these new exploration areas are the best available. The number of blowouts per wells drilled has decreased in recent years. Figure 1 illustrates statistics on various features of blowout cases. Note from this data the type fluid, time to control, and the number of wells that require drilling a directional well to control the blowout. tiny conventional methods have been developed to control subsea blowouts and to direct and control the well flow either at the ocean floor or at the ocean surface. There are several wells that blowout each year which require special diverting and control techniques. SEDCO investigated a special technique for wells where the well flow was coming out of the subsea BOP or from a casing leak below the BOP where the BOP was intact but not controllable. An example of the above blowout which required a special diverting and control technique is illustrated on Figure 2. Consider that to mobilize and drill a directional well before pumping for the well kill operations, would require a minimum of 60 to 90 days. During this time, the uncontrolled well flow would be flowing to the ocean surface where it would be necessary to add dispersants, channel hydrocarbons to a cleaning system, and burning oil and gas residue. Depending upon the types of hydrocarbon and the wind/wave conditions, the surface collection and disposal can be 50% and less efficient. Figure 3 illustrates several ocean surface views of subsea blowouts. This paper presents a method which can be used to collect and dispose of a subsea well blowout effluent with a 90% collection efficiency rate. Figure 4 illustrates a subsea funnel which can be fabricated at any site, installed on an offshore boat or barge, and then the funnel positioned over the subsea blowout. The well flow (oil/gas) will aerate/expand and move the funnel directly over the well. The gas from the subsea blowout will flow up the funnel/riser to the surface and lighten the column to the point which water and well fluids (oil) will enter the funnel and flow to the surface. At the surface the fluids flowing through the pipe will be directed to a large separator. The three phase separator will direct fluids to a storage or disposal facility. This funnel method of diverting and controlling a subsea well is the subject of this paper. The model tests and a proposed full scale unit are included in this paper. The MMS has funded a study of the funnel method of controlling subsea blowouts. p. 189
- Well Drilling > Pressure Management > Well control (1.00)
- Health, Safety, Environment & Sustainability > Safety > Operational safety (1.00)
- Health, Safety, Environment & Sustainability > HSSE & Social Responsibility Management > Contingency planning and emergency response (1.00)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems (1.00)
Abstract In the shadow of low oil prices, it is necessary to develop economically and environmentally friendly solutions. In oil and gas industry, majority of the production stream is water. This water is produced with the hydrocarbon to surface. This requires the separation of the fluids produced and then treating those streams to abide with environmental regulations and clients' specifications. CDOWS (Centrifugal Downhole Oil Water Separator) technology is believed to provide high separation quality, high oil recovery with reduction of operating costs and less surface facilities. The development process involves simulation of tubular centrifuge using a computational fluid dynamics (CFD) software to analyze the parameters affecting separation. After that, an experimental set up is erected which mimics in-well CDOWS. The novel design of the tool involves specially designed weir to collect the oil and water through concentric tube configuration. The parameters tested through simulation include; flow rate, RPM, tubing length, tubing diameter, API and oil/water ratios. The experimental set-up is used to confirm the sepration in the rotating tube as it is made of acrylic material. The CFD model involves a rotating cylinder (tubing) in which oil and water are introduced from the inlet. The feed of oil and water exhibits high centrifugal forces resulting in their separation through and to the outlet of the tubing. The experimental design mimics the actual in-well design which can be implemented in a well. The design can be configured easily to change the tubing parameters. After conducting the studies, a sensitivity analysis using design of experiment approach (DOE) and response surface plots is produced to emphasize on parameters and their interaction effects. Findings include better separation using higher RPM, ID, L, water salinity, API. The most influential factor is RPM which can be controlled and thus will define costs for later stages of the project. This paper presents the first work on CDOWS which is analogous to in-well configuration aiming for a solution with reduced costs.
- Research Report > Experimental Study (0.64)
- Research Report > New Finding (0.50)
Taking Advantage of Multiphase Flow Reversals Enhances Downhole Gas and Solids Separation for Artificial Lift
Saponja, Jeff (Oilify) | Hari, Rob (Oilify) | Brignac, Justen (Oilify) | David, Sean (Oilify) | Jaszan, Dayley (Oilify) | Coyes, Corbin (Q2 Artificial Lift Services) | Nagoo, Anand (Nagoo and Associates LLC) | Penner, Brandon (Calyx Energy III LLC)
Abstract Downhole separation of gas and solids for sucker rod pumping (SRP) and electrical submersible pumping (ESP) continues to be a significant challenge, particularly for horizontal wells. A major advancement in downhole separation has been achieved by realizing there was an opportunity to intentionally take advantage of transient multiphase flow conditions where liquids phase reversals or fallback exists. Multiple case studies demonstrate that designing of a downhole separator that takes advantage of liquid phase flow reversals can enhance downhole separation performance and capacity, while at the same time lower operational risk. Improving downhole separation without undesirably increasing operational risk and cost has been challenging. A separator design that requires a packer or annular seal, such as a cup, is inherently more operationally risky from an installation and retrieval perspective. Further, a separator design that imparts pressure drops or increases flow turbulence faces the reliability risks of scale deposition and erosion. Flow turbulence can increase the entrained gas foaming tendency in the liquid and reduce gas bubble size in the liquid, consequently lowering separation efficiency and increasing pump gas interference. It is generally understood that separation capacity, in terms of gravity separation principles, has been physically limited by a separator's cross-sectional area for separation. It is less understood that separation capacity has also been limited by the location and orientation of a separator's intake, as well as the shape of the conduit in a separator's separation region, and that it has been limited by a common mechanical design practice of a concentric or centralized pump intake dip tube or mandrel. Technical literature, industry research and transient multiphase flow simulations have revealed, under certain conditions, that liquid phase flow reversals are not only present, but also occur at high frequencies. Such reversals or liquid fallback also occurs at much higher velocities than gas bubbles can rise, which suggested there is an opportunity to improve downhole separation. Industry research also disclosed that gas-liquid separation in an eccentric annulus is more efficient than in a concentric annulus and that separation efficiency is greater in a conduit shaped as an open tube versus an annulus. Such gains in separation efficiency are primarily due increased liquid hold-up, meaning increased liquid phase flow reversals or liquid fallback. It was hypothesized that downhole separation could be significantly improved by a separator engineered to take advantage of liquid phase flow reversals, thereby avoiding the limitations of downhole separators that are governed by gas bubble rise velocity. A separator was then designed, built, extensively flow loop tested and successfully field implemented. This paper describes the design process and results of the field implementation of an enhanced downhole separator. Flow loop testing results and comprehensive analytical transient multiphase flow simulation will be shared. A set of case studies, in multiple basins, reviews the field installations and presents the results of improved downhole separation performance and lowered operational risks, resulting in lowered operating expense and increased production.
- North America > United States > Colorado (0.46)
- North America > United States > Texas (0.28)
- North America > United States > Oklahoma (0.28)
- North America > United States > Wyoming > Niobrara Formation (0.99)
- North America > United States > West Virginia > Appalachian Basin (0.99)
- North America > United States > Virginia > Appalachian Basin (0.99)
- (41 more...)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Multiphase flow (1.00)
- Production and Well Operations > Well Operations and Optimization > Downhole fluids separation, management and disposal (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- (2 more...)
Installation of GRE Pipeline in Bunduq Offshore Field. Abstract Production losses of up to 100,000 STB per year were created by the need for testing at an offshore wellhead platform with multiple wells. This led the operator to take a course of action to reduce these losses. Todays paper covers investigation of the alternatives considered. The selection and installation of a Glass Reinforced Epoxy (GRE) test flow line as the solution to the problem. Introduction A remote multi well platform, located in an Abu Dhabi Offshore Field and having a 270 meter ion flow line to a Central Collector Platform had no test facilities. Consequently when one well was to be tested the other wells had to be shut down leading to significant losses in production. As future plans are for additional wells on the Wellhead Platform, production losses would increase with an increase in flow testing requirements. A number of options were assessed. Installing a separate GRE flow line was considered the most viable both economically and technically. Options Considered 1. Installation of a Multiphase Flow Meter This option appeared to be the most economical. However, at the time of evaluation the equipment was unproven and not considered to be sufficiently accurate (10%). Extensive piping modifications would have been required to install a test header facility as well as a data link to the main complex. 2. Use of Barge Mounted Test Facilities This option was considered and rejected as a viable alternative. The system is too dependent on weather conditions and was not considered to be cost effective in the long term. 3. Installation of a Test Separator on the Wellhead Platform. The installation of a test separator on the Wellhead Platform was found to be the highest cost option, as major modifications would be required. P. 118
- Asia > Middle East > UAE > Abu Dhabi Emirate > Abu Dhabi (0.36)
- Asia > Middle East > UAE > Abu Dhabi Emirate > Arabian Gulf (0.24)
- Well Completion > Completion Installation and Operations (1.00)
- Facilities Design, Construction and Operation > Processing Systems and Design > Separation and treating (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers (1.00)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems (1.00)
ABSTRACT: The motion characteristics of a towed collector for a manganese nodule mining system which consists of a mining ship, lifting pipes, flexible hoses and the collector are investigated by realistic computer simulations. The collector is controlled by the ship" s tow only. Three typical scenarios are simulated: collector towed at sea, collector towed at sea bed, and collector landing on the sea bed. Some ship speed is important to avoid kinks in the hose at landing. Current from abaft removes landing problems. Two tugs may be necessary to operate safely in adverse wave and wind conditions. INTRODUCTION The Agency of Industrial Science and Technology, the Ministry of International Trade and Industry Japan, started a large-scale project entitled "The Research and Development Project of Manganese Nodule Mining System" in 1981. Much research and development for the mining system has already been performed, e.g. Wakabayashi (1986), Oyama (1990). The mining system in the project is a hydraulic mining system in which nodules are collected by a towed collector on the sea bed and transported in a slurry of sea water and nodules through the lifting pipes onto the mining ship, Fig.1. The pipe strings are suspended by the gimbals on the mining system. The lifting pump modules and the air inlet nozzles are installed in the pipe strings. Flexible hoses are connected to the lifting pipes to assure flexibility near the sea bottom. Fig.2 shows a bird" s eye view of the investigated collector. The collector has sleds as traveling mechanism and a fin to keep stable in currents. It is connected to the end of the flexible hoses. Table 1 shows the principal dimensions of the collector and the stabilizing fin. This system is simple and reliable, but the efficiency of the sweep may be limited as the system is not self-propelled.