For decades, efforts have been made to automate the HAZOP process. The motivation has mainly been to displace expensive manual HAZOP approaches, that are furthermore known to suffer from systemic quality issues related to system complexity, uncertainty, vagueness and level of knowledge completeness. With offset in a review of the main historic arguments for automating the HAZOP analysis, and an outline of the particular benefits of employing Multilevel Flow Modelling (MFM) theory in this context, this paper emphasises the opportunity to redeploy the insights achieved by the HAZOP team to assist an operator facing an abnormal event years later. By means of a detailed analysis of an actual catastrophic failure of a FPSO compression module, the paper demonstrates how MFM enabled HAZOP captures explicitly tacit expert knowledge about the complex interdependencies between process design, equipment design, safety barriers and instrumentation. The paper further describes a methodology to interpret measurements online by means of the MFM analysis, thereby establishing real-time cause and consequence analysis in sufficient time to interrupt the escalation from a benign sensor malfunction to a topside explosion.
Wu, Jing (China National Offshore Oil Corporation (CNOOC) Ltd., Tianjin Branch) | Wang, Mingchun (China National Offshore Oil Corporation (CNOOC) Ltd., Tianjin Branch) | Gao, Lei (China National Offshore Oil Corporation (CNOOC) Ltd., Tianjin Branch) | Gao, Wenbo (China National Offshore Oil Corporation (CNOOC) Ltd., Tianjin Branch) | Jiang, Tao (China National Offshore Oil Corporation (CNOOC) Ltd., Tianjin Branch)
Summary Shaleitian uplift is a typical conjugate area controlled by the NEtrending faults Huanghua-Dongming (H-D faults) and the NWtrending faults Zhang-Peng (Z-P faults).The two sets of faults not only control the formation and evolution of the uplift but also influence the key factors of hydrocarbon accumulation of it and surrounding. The land part of Z-P fault is studied relatively more, but few studies on the seat part as the main reason is lack of 3D seismic data.Research shows that oil and gas accumulation is closely related with Tan-Lu fault and Zhang-Peng fault in Bohai Bay Basin.Therefore, It's necessary to do further research about Z-P fault and the conjugate area of the H-D and Z-P fault. By means of the horizontal and vertical characters in plane and seismic profile, we can be certain of the geometry characteristics of the H-D and Z-P faults. Although the strike-slip property of the faults makes stress mechanisms complicated, the physical simulation experiment about the typical faults helps to do more in-depth analysis. According to the geometry characteristics and the stress field that the faults have been experienced, we built simplified evolution model of the faults.
Fu, Qiang (M-OSRP, Physics Department, University of Houston) | Zou, Yanglei (M-OSRP, Physics Department, University of Houston) | Wu, Jing (M-OSRP, Physics Department, University of Houston) | Weglein, Arthur B. (M-OSRP, Physics Department, University of Houston)
The Inverse Scattering Series (ISS) internal multiple attenuation algorithm can predict the exact time and approximate amplitude of every internal multiple at all offsets at once. This algorithm does not require any subsurface information and it is model-type independent. When the primaries and multiples are isolated, the ISS internal multiple attenuation algorithm plus energy minimization adaptive subtraction can effectively eliminate internal multiples independent of the the medium model type (e.g. acoustic, elastic, anisotropic, inelastic, etc.). However, when internal multiples are proximal to and/or interfering with a primary, the energy-minimization adaptive subtraction can fail. In proximal /interfering cases the ISS elimination algorithm is needed for predicting the exact time and exact amplitude of multiples, and it would not depend on the energy minimization criteria to fill the gap between attenuating and eliminating the internal multiple. Thus M-OSRP proposed developing ISS internal multiple elimination algorithm to accommodate these proximal/interfering cases. We have an interest in examining the issue of the elimination of interfering internal multiples for increasingly realistic subsurface circumstances. We also recognize the benefit of studying each step of added realism and complexity in isolation. Absorption/dispersion can have a very significant impact on amplitude, often more significant than the acoustic/elastic differences. There is a line of research in the ISS initiative that extends the development and analysis to the absorptive/dispersive world by studying an acoustic absorptive medium. For example, Innanen and Weglein (2003, 2005); Innanen and Lira (2008, 2010); Wu and Weglein (2014). This paper follows that line of contributions and extends ISS internal multiple elimination to absorptive/dispersive acoustic medium, which is the simplest world with an absorptive/dispersive property. We test the current ISS internal multiple elimination algorithm on synthetic data (P-only events) from attenuating medium both analytically and numerically. The analysis and results of the tests show that the current elimination algorithm predicts P-only internal multiple in an absorptive/dispersive medium with both the exact time and amplitude if the absorption/dispersion (finite Q) is only located beneath the generator (which is where the the downward reflection occurs) of the first-order internal multiple, without knowing the medium and its absorptive/dispersive properties. Under this type of circumstances the current ISS internal multiple elimination algorithm is fully effective in predicting accurate P-only internal multiples in an absorptive/dispersive medium. That is positive news for the exploration plays where absorption is only significant below the major internal multiple generators. For instance, that can be the situation for a single absorptive salt body. In this case the major internal multiple generator is often either the water bottom or the top of the salt body and the major attenuation happens within the salt body. Thus the absorption is only existing below the generator, the current acoustic based elimination algorithm is sufficient for predicting an effective P-only internal multiple in this type of exploration play.
Presentation Date: Monday, October 15, 2018
Start Time: 1:50:00 PM
Location: 211A (Anaheim Convention Center)
Presentation Type: Oral
Dragoset, W., 2014, Challenges in data-driven multiple prediction and attenuation: KOC/SEG research workshop on Multiples, Kuwait City, Kuwait.
The Green’s theorem wave-separation methods (e.g., separating the reference wave and the reflection data, and deghosting) have an important property of naturally accommodating an arbitrary measurement surface. However, for non-horizontal acquisition, those methods cannot locate the output point on the surface where the input data is acquired. For example, in order to effectively predict the receiver-side deghosted data, the current algorithm originating from Green’s theorem wave separation has to output the deghosted result at a depth that is shallower than the actual acquisition location. If the measurement surface is horizontal, the Green’s theorem deghosting algorithm can be expressed in the wavenumber domain, and is equivalent to the widely used PVz method, and it can locate the output result on the measurement surface. However, the PVz method is not applicable with a non-horizontal acquisition surface. To overcome this drawback, this paper develops a two-step method that can achieve receiver-side deghosting right on the measurement surface and without assuming the measurement surface to be horizontal. Therefore, it can deghost the actual acquired data. The new method derives from both Green’s theorem based wave separation and one-way wave prediction. The shape of the measurement surface is assumed known. This idea is also viable for source-side deghosting. We develop the method and illustrate with synthetic examples, considering a towed streamer in the water column. It is worth noting that onshore and ocean-bottom acquisition can often have a significantly variable topography and can also benefit from the new method in this paper.
Presentation Date: Monday, September 25, 2017
Start Time: 2:40 PM
Presentation Type: ORAL
Wu, Jing (Department of Electrical Engineering, Technical University of Denmark) | Lind, Morten (Department of Electrical Engineering, Technical University of Denmark) | Asheim, Bjarne André (Eldor Technology AS) | Jørgensen, Sten Bay (CAPEC-PROCESS, Dept. of Chemical and Biochemical Engineering, Technical University of Denmark) | Jensen, Niels (Safepark)
Industrial processes contain inherent risks and to assess such risks the use of Process Hazard Analysis (PHA) are commonly applied. The benefits of first principles qualitative and quantitative models and empirical knowledge support for PHA are explored. The use of qualitative hazard analysis based on functional modelling to guide hazard analysis is emphasized.
The study proposes a framework for investigating potential hazard scenarios based on functional modeling, e.g. Multilevel Flow Modeling of process system. Subsequently quantitative hazard analysis is used to prioritize the hazard scenarios with highest potential. MFM represents the process on several levels of abstraction and supports logical inference. The potential hazard scenarios are ranked by likelihood and severity. Judgment about likelihood, severity and the tolerability of the resulting risk is made on a subjective basis using the empirical knowledge of the PHA team members. The potential hazard scenario generation procedure can be computer-aided. The proposed framework is applied for a water injection system to increase oil recovery from existing reservoir with better safety performance.
Qualitative functional models are efficient for detailed description of possible accident scenarios. Domino effects can be visualized in an MFM model. The possible major accident scenarios are selected by likelihood and severity of their effects. The major accident scenarios can be examined in detail through further quantitative analysis. The hazard analysis of a water injection system demonstrates the feasibility and applicability of the proposed framework.
In industrial practice, formulation of the major accident scenario is usually based on historical incidents and the outcome of HAZOP/HAZID type hazard identification studies. Such studies are dependent on the team and their collective knowledge rather than being systematic and objective in nature. The proposed framework performs systematic and comprehensive plant failure and consequence path generation by a computer-aided tool.
Weglein, Arthur (University of Houston) | Mayhan, James (University of Houston) | Zou, Yanglei (University of Houston) | Fu, Qiang (University of Houston) | Liu, Fang (University of Houston) | Wu, Jing (University of Houston) | Ma, Chao (University of Houston) | Lin, Xinglu (University of Houston) | Stolt, Robert (Retired)
There is an industry wide interest in acquiring lower frequency seismic data. There is also an interest in assuring that the broadband data provides added value in processing and interpretation, to better resolve structure and to provide improved amplitude analysis at the target and at the reservoir. There are industry reports that when comparing the new and more expensively acquired broadband lower frequency data with conventional recorded data, taken over a same region, that these two datasets have the expected difference in frequency spectrum and appearance, but they provide little or no difference in structural improvement or added benefit for amplitude analysis at the target and reservoir. The methods that take recorded data and determine structure and perform amplitude analysis are migration and migration-inversion, respectively. There are two objectives of this paper: (1) to demonstrate that all current migration and migration inversion methods make high frequency asymptotic assumptions, that consequently do not provide for equal effectiveness at all recorded frequencies, at the target and reservoir. The consequence is that in the process of migration, they lose or discount the information in the newly acquired lowest frequency components in the broad band data, and (2) we address that problem, with the first migration method that will be equally effective at all frequencies at the target and reservoir, and will allow the broad band lower frequency data to provide improved structure and more effective amplitude analysis. Seismic acquisition and seismic processing must be consistent and aligned to provide interpretive value from broad band data.
Deghosting is a key step for ocean bottom seismic data processing. For measurements at the seafloor, notches can occur within the spectrum at much lower frequencies than for towed streamer data. Removing ghosts can improve seismic resolution. In addition, the subsequent steps (e.g., multiple removal, imaging and inversion) will all benefit from effective deghosting. In this paper, based on Green’s theorem, we provide distinct methods to separate (1) the pressure data that are collected just above ocean bottom, and (2) the multicomponent displacements that are acquired below the seafloor, into up and down waves. Synthetic tests demonstrate the promise and potential of this method for deghosting ocean bottom data.
Presentation Date: Wednesday, October 19, 2016
Start Time: 10:20:00 AM
Presentation Type: ORAL
Green's theorem based onshore preprocessing - a reduced data requirement assuming a vacuum/earth model for the air/earth interface and the evaluation of the usefulness of that assumption SUMMARY The elastic Green's theorem wave separation method can effectively reduce ground roll and ghosts in land data, and most importantly, without harming reflection data. Both tractions and multicomponent displacements are assumed in the original elastic Green's theorem method (Wu and Weglein, 2015a). However, it is not easy to measure tractions directly. In order to reduce the requirement of traction, this paper simplifies the algorithm assuming that the acquisition is on a vacuum/earth surface. The new formula requires the traction at only the source point rather than all the points along the measurement surface.
Combined with the distribution of volcanic rocks in the southwest of Bohai region and the latest research results, we comprehensively analyze the lithologic features, logging characteristics and seismic reflection of different volcanic rocks. The development characteristic of the volcanic rocks has been investigatedand a prediction model mainly featured with quiet central eruption has been established in BZ 34-X area.
Under the constraint of this model, we have identified and summarized three major lithofacies of volcanic rocks by using seismic reflection characteristics and corresponding attributes: volcanic conduit, effusive and explosive facies. Consequently, an identification plot template which is adaptable in this regionhas been made based on drilling and seismic data.Preliminary quantitative attribute parameters are acquired by using well-tie results from exploration wells in BZ34-X area. Under the control of these parameters, the 3D quantitative description of the volcanic rocks with the application of Geoframe platform was realized.
Finally, the main eruption period of volcanic rock and its control action onthe structure trap and accumulation of oil and gas have been determined with the help ofgeological analysis. 3D quantitative description techniques efficiently predict the spacial distribution of the volcanic rock in BZ34-Xarea, also effectively guide the well deployment and reduce engineering risk.The predictedvolcanic eruption pattern and two stages of eruption were demonstrated by later drillings.
The commercial production of Lapaz Oilfield, which was found in 1953 from Venezuela, draws the attention to the igneous reservoir. There are so far more than 300 igneous reservoirs, which was easy to identify for its huge extent, single eruption, thick layer and early igneous intrusion. However, there are few successful cases in the complex geological body of “volcanic rocks and disturbed sedimentary rocks” in Cenozoic reservoirs due to its multiple eruption periods, the small thickness and mixed lithology.
Cenozoic volcanic rocks are distributed in many tectonic areas in the southwest of Bohai, such as western zone of Shaleitian uplift, Laibei low uplift, Bozhong and Kenli structure area. The area of volcanic rocks in the southwest of Bohai Sea is up to 3000km2. Multiple eruptions existed from Shahejie and DongYing formation of Paleogene to GuanTao formation of Neogene. The eruption period of different tectonic zones is not the same, and the thickness of volcano rock is from several meters to hundreds of meters. Due to the unclear distribution of volcanic rock, thecomplicatedmechanism of eruptionand multiple eruption periods, theseareas ever became the forbidden exploration zones.