Research on the SimulationResearch on the SimulationSub sea DispersantSub-sea Dispersantp

An Weia b; Li Jian eia b; QiaAn Weia,b; Li Jianweia,b; QiaAn Wei ; Li Jianwei ; QiaS Sh hSong ShashSong Shash

a China Offshore Environmental Services La. China Offshore Environmental Services Lb C t f Off h Oil S f t d E i tb. Center for Offshore Oil Safety and Environmentay

Contact: anweiContact: anwei

IntroductionIntroduction

In recent years we have been faced with increasingly growing risks ofIn recent years, we have been faced with increasingly growing risks ofd il ill i h h id d l f ff h il ddeepwater oil spill with the rapid development of offshore oil and gasp p p p gindustry especially the oil & gas exploration and development projectindustry, especially the oil & gas exploration and development projectd l d b Chi i h d S b ill d il h ldeveloped by China in the deepwater area. Subsea spilled oil has severelyp y p p yimpaired both marine environment and mankind in the entire process inimpaired both marine environment and mankind in the entire process in

hi h it t t b d d ll th t fwhich it enters water body undersea all the way to sea surface.

In this paper the classic Lagrangian integral method and the particle trackingIn this paper, the classic Lagrangian integral method and the particle trackingare used to construct a deepwater oil spill model and a 3D visualizationp psystem for dynamic prediction of underwater oil spill has been developedsystem for dynamic prediction of underwater oil spill has been developed.Besides, on the basis of summarizing the state of art of oil spill dispersant, g p pdevelopment and the evaluation technology of its sea surface and underwaterdevelopment and the evaluation technology of its sea-surface and underwater

li i ff h h b di i h b i dapplication effect, research on the sub-sea dispersants using has been carriedpp , p gout in the laboratoryout in the laboratory.

Deepwater Oil Spill Numerical Simulation TechnologyDeepwater Oil Spill Numerical Simulation Technology

High-Resolution Hydrodynamic Prediction in South China Seag y yD li d i h S h Chi S h l idDue to complicated terrain, the South China Sea has a complex tide wavep psystem and high tidal dissipation In addition internal tide occurs frequentlysystem and high tidal dissipation. In addition, internal tide occurs frequentlyi th S th Chi S th f i ti l di i ti t f ll fl t thin the South China Sea; thus, frictional dissipation cannot fully reflect theactual conditions of tidal dissipation in the deep water Therefore an internalactual conditions of tidal dissipation in the deep water. Therefore, an internaltid l di i ti t i dd d t th t diti l 2D tid titidal dissipation term is added to the traditional 2D tide wave equation.

I d t i th i l ti it i i d t ti i thIn order to improve the simulation accuracy, it is required to optimize thebottom-friction factor and internal tidal dissipation factor if adjointbottom friction factor and internal tidal dissipation factor if adjoint

i il ti th d i d t d I i il t d i l ti h t h kassimilation method is adopted. In assimilated simulation , we have to checkhow to make the simulation results closest to the observed value.how to make the simulation results closest to the observed value.

Deepwater Oil Spill Simulation and Testp pA di h b h i f h il d l d b bbl i i i hAccording to the behavior states of the oil droplets and bubbles in rising, theg p g,deepwater oil spill can be divided into 3 stages: jet stage buoyant plume stagedeepwater oil spill can be divided into 3 stages: jet stage, buoyant plume stage

d d i diff i Th fi b ll i l dand advection diffusion stage. The first two stages can be collectively namedg g ynear-field stage and the third stage can be also named far-field stage At thenear-field stage, and the third stage can be also named far-field stage. At the

fi ld ll l h li b d d i fnear-field stage, pollutants along the center line can be regarded as a series ofg p g gindependent control units and each unit can be expressed with massindependent control units, and each unit can be expressed with mass,

t ti t t d li it t Th ti l ti f th t lconcentration, temperature and salinity, etc. The spatial motion of the controlunits reflect the spilled oil trajectory The concentration change of the controlunits reflect the spilled oil trajectory. The concentration change of the control

it i di t th d ti f th ill d il t ti Th f fi ld tunits indicates the reduction of the spilled oil concentration. The far-field stageis a stage after the pollutants reach the neutral buoyancy level At this stageis a stage after the pollutants reach the neutral buoyancy level. At this stage,

l l t l l th i iti l t d th il d bplumes completely lose the initial momentum and the oil and gas can beregarded as oil droplets and bubbles of different particle sizes which moveregarded as oil droplets and bubbles of different particle sizes which move

d th ff t f b d t flunder the effect of buoyancy and transverse flow.

In order to simulate the whole process of underwater oil spill acquire effectiveIn order to simulate the whole process of underwater oil spill, acquire effectivetest data and verify the accuracy of the built deepwater oil spill model, wey y p p ,produced a pressure device to simulate the HP/LT deepwater environmentproduced a pressure device to simulate the HP/LT deepwater environmentconditions. This device can carry out deepwater oil spill simulation at differenty p ppressure temperature and jet velocity and further study the behavior and fate ofpressure, temperature and jet velocity and further study the behavior and fate ofdeepwater oil spill. The main body of the device is a 2m (height) ×0.3m (innerp p y ( g ) (diameter) cylinder with a bearing pressure of 10MPa which is composed ofdiameter) cylinder with a bearing pressure of 10MPa, which is composed oftank, jetting system and data collection system (Fig.1)., j g y y ( g )

Fig 1 Design Sketch of Deepwater Oil Spill Simulation DeviceFig 1. Design Sketch of Deepwater Oil Spill Simulation Device

Development of 3D visualization system for deepwater oil spillp f y f p pBased upon the offshore hydrodynamic prediction model and the results ofBased upon the offshore hydrodynamic prediction model and the results ofdeepwater oil spill simulation we simulated the whole dynamic motiondeepwater oil spill simulation, we simulated the whole dynamic motionprocess of deepwater oil spill and developed a 3D visualization system forprocess of deepwater oil spill and developed a 3D visualization system fordeepwater oil spill This system can calculate the trajectory of each spilled oildeepwater oil spill. This system can calculate the trajectory of each spilled oilparticle by using nonlinear rapid interpolation method based upon the locationp y g p p pparameters of the spilled oil substancesparameters of the spilled oil substances.

n for Deepwater Oil/Gas Spills andn for Deepwater Oil/Gas Spills andp pts Application Experimentsts Application Experiments pp p

an G odonga b ; Zhao Y penga b;an Guodonga,b ; Zhao Yupenga,b;an Guodong ; Zhao Yupeng ; a b Ji W i ia baa,b; Jin Weiweia,ba ; Jin Weiwei

Ltd Tanggu District of Tianjin 300452 ChinaLtd., Tanggu District of Tianjin, 300452 , Chinal T h l Qi d f Sh d 266061 Chial Technology, Qingdao of Shandong, 266061 , Chinagy, g g, ,

2@cnooc com cn2@cnooc.com.cn

Fi 2 I f f h 3D Vi li i S f D Oil S illFig 2. Interface of the 3D Visualization System for Deepwater Oil Spill

Experimental Research of Subsurface Dispersant UsingExperimental Research of Subsurface Dispersant Using In order to investigate the effect of oil spill dispersant on underwater spilledIn order to investigate the effect of oil spill dispersant on underwater spilled

il b il k f i l h f di b foil, we built a tower tank for experimental research of dispersant subsurface, p pusing according to the underwater oil spill characteristics and oil spillusing, according to the underwater oil spill characteristics and oil spilldi j i d Th k i h i Fi 4 Th fl idispersant jetting needs. The tower tank is as shown in Figure 4. The flume is ap j g gcompletely transparent glass channel with the physical dimensions of 2 m×1completely transparent glass channel with the physical dimensions of 2 m×1× 1 (h i h × l h × id h) hi h i bl h ld 2 3 fm× 1 m (height × length × width), which is able to hold 2 m3 of seawater.( g g )

The tank bottom has two orifices one for crude oil blowout and another forThe tank bottom has two orifices, one for crude oil blowout and another fordi t i j ti ll i t i l t il ill di t i j ti ddispersant injection, allowing to simulate oil spill dispersant injection underthe subsea blowoutsthe subsea blowouts.

Fig 3. Tower Tank for Subsurface Dispersant Using ExperimentFig 3. Tower Tank for Subsurface Dispersant Using Experiment

Th i i h i j i ifi i l i i kThe experiment starts with injecting artificial seawater into experiment tankp j g puntil the water depth reaches 1 7 m The oil tank is then filled withuntil the water depth reaches 1.7 m. The oil tank is then filled with

i t l d il hi h j t f th b tt i t t b d ith thexperimental crude oil which ejects from the bottom into water body with thehelp of the pressure pump Next an oil spill dispersant jetter is used to injecthelp of the pressure pump. Next, an oil spill dispersant jetter is used to inject

il ill di t i t th il j t t ll th di t t il ti (DOR) toil spill dispersant into the oil jet to allow the dispersant-to-oil ratio (DOR) toreach a specific valuereach a specific value.At th h i ht 1 5 f th b tt i d t it th jAt the height 1.5 m from the bottom, a camera is used to monitor the majorprofile of spilled oil from a side of the tank At the adjacent side of the flume aprofile of spilled oil from a side of the tank. At the adjacent side of the flume, a

i i d t it di t d t f il d l t N t d tmicroscope camera is used to monitor diameter data of oil droplets. Next, dataare extracted from the oil droplet diameter information pictures and the oilare extracted from the oil droplet diameter information pictures and the oild l t i di t ib ti i l d Aft i t l t ldroplets size distribution is analyzed. After an experiment cycle, water samplesare collected to determine oil concentration and surface tension data. Theare collected to determine oil concentration and surface tension data. Theeffect of subsurface dispersant injection on subsea blowoutseffect of subsurface dispersant injection on subsea blowouts.

i 4 h ff f S b f i j i S b lFig 4. The Effect of Subsurface Dispersant Injection on Subsea Blowouts

ConclusionConclusionThe model of deepwater oil spill & 3D visualization system has beenThe model of deepwater oil spill & 3D visualization system has beend l d d b di t li ti i t h b i ddeveloped and sub-sea dispersants application experiments has been carriedout to provide technical support for deepwater oil spill emergency response.

R fout to provide technical support for deepwater oil spill emergency response.

ReferenceJohansen, Ø. 2003. Development and verification of deep-water blowoutJo a se , Ø. 003. eve op e t a d ve cat o o deep wate b owoutmodels Mar Pollut Bull 47 360 368models. Mar Pollut Bull. 47, 360-368.Zheng, L., Yapa, P.D., Chen, F., 2003. A Model for Simulating Deepwater Oilg, , p , , , , g pand Gas Blowouts Part I: Theory and Model Formulation Journal ofand Gas Blowouts-Part I: Theory and Model Formulation. Journal ofHydraulic Research 41, 339-351.y ,