The aim of the study is to analyze the change order issue in oil and gasconstruction projects. It will be done by understanding current methods that are practiced for dealing with this problem and examining the suitability of the current change order clause in oil and gas contracts and finally, methods related to more effective change order control will be suggested. Therefore, In order to achieve the aim the following objectives have been set.
38 oil and gas sector in Saudi Arabia. In this regard, it can be seen that the oil and gas sector in Saudi Arabia is a major contributor to the high volumes of construction projects in the Kingdom. As a country with large deposits of oil and an emerging economy, the oil and gas sector in Saudi Arabia embarks on many construction projects. Research by Albassam, (2015)suggests that the oil and gas sector remains the driving force in the Kingdom of Saudi Arabia. For the purposes of this research, oil and gasconstruction projects relate to projects that are undertaken for the purposes of oil and gas exploration activities. Construction activities within the oil and gas sector cover main projects such as: offshore construction activities including the construction of oil platforms and production lines, offshore oil fields, gas pipelines, oil refineries, drilling facilities and accommodation for the purposes of oil and gas explorations. Taylor and Carson (2014) report that the construction of large onshore oil and gas processing plants bring large economic contributions. Ruqaishi and Bashir (2015) report that oil and gasconstruction projects in the gulf region have many challenges including delays. Research by Chen (2011) suggest working in oil and gasconstruction projects is both challenging and hazardous due to the remote and hostile work environment and the demanding shift work schedules, which often necessitate daily adaptation. Berends (2007) presents results which suggest that large engineering and construction projects such as those involved with oil and gas operations are technically complex involving the integration of many different technical disciplines on the basis of a large codified body of knowledge.
Abstract: Oil and gasconstruction projects are complex and risky because of their dynamic environment. Furthermore, rising global energy demand has increased the need for trustworthy risk assessment models for such projects that can provide adequate and precise policy planning. Traditional risk assessments in oil and gasconstruction projects do not consider the interrelationships of factors in the best-fit models. The Decision Making Trial and Evaluation Laboratory (DEMATEL) and Analytic Network Processes (ANP), called the DEMATEL-ANP approach, have been applied to other research disciplines to address this shortcoming. This method is able to construct a structural relationship among the different influence factors to visualize complex correlations. Thus, the purpose of this study is to showcase the DEMTAL-ANP risk assessment model to assess the overall risk factors of OGC projects. This study thus identifies the crucial risk criteria of such projects. Data were collected in 2016 through interviews with experts active in OGC projects in Iran. DEMATEL in this situation is used to determine the interdependencies’ relative strengths among the risks. The ANP method is applied to assess the relative importance of the risk factors and to determine the best strategy for implementation of a risk management program. The results presented in this study are a novel adaptation of the risk assessment methodology to OGC projects that determines the important risk factors that directly affect the project success, which in turn helps in formulation of policies for ensuring reliable energy supply planning.
In managing offshore oil and gas projects, the role of senior managers and safety leadership can never be over emphasised. It has been often argued that effective safety leadership can decrease human errors and incident rate. In support of this notion, The United States Occupational Safety and Health Administration (OSHA) (1996) recognized the power of leadership and identified management leadership as a key element in safety issues. According to , Safety leadership that motivates team members to work harder, efficiently, and take ownership of responsibilities for safety performance should upheld. Furthermore, Health and Safety Executive (HSE) in UK articulated that without effective leadership, good safety performance cannot be achieved. From the foregoing, broad conclusions indicating that safety leadership supports increased organizational safety effectiveness can be drawn. Therefore, developing and sustaining safety leadership is important to reduce accidents and to promote safety among personnel. Accordingly, this paper posits that the way forward for safety in offshore oil and gas project operations must be instigated by senior managers’ and safety leadership. This is because their actions usually introduce rippled effects on the entire organisation and can galvanise greater levels of safety awareness within organisations.
In handling such mega projects, they have been dealt with many obstacles to achieve until these milestones. Hence, Company A needs to provide essentials services to its customer with commitment to deliver on time, within budget with good quality and in any environment they are ready to place their services. However, in construction site the risk exposure is relatively high, despite that much effort has been put in place by the Company A. With the numbers of the internal and external stakeholders that involved in every project, it is vulnerable for Company A to expose with risks be it positive or negative impact.
Waste analysis and proposed improvements are carried out only on waste related to engineering works, because only those fields are carried out by the company itself and to prevent occurrence of the other waste in other process which use the output of engineering (procurement and the construction process). A project engineering document grade can be approached based on the value of the amendment of the work, a brainstorming approach with expert in company as shown in Table 5 Project Engineering Documents Grade Based on Amendment Values.
delay in approving major changes in scope of work. These find- ings were categorised as client, external and engineering issues. Delay on completions of oil and gasconstruction projects ranges between five to twenty percent of the entire project timeframe (35). This leads to loss of revenue to the owner due to deferral of pro- duction and results in higher cost to the contractor due to fixed costs stated Simanjuntak and Mahendrawan (35). The cause of delay identified by Simanjuntak and Mahendrawan (36) are insuf- ficient funding, inadequate experience of contractor, impractical allocation of resources, slow decision making process, poor coor- dination of subcontractors, incompetent site management, permit approval - local and central government and support from other sectors.
Figure 10. CO 2 e emission of different phases in cement-stabilized course construction excluding raw
materials production process (unit: kg). 5.3. Discussion and Recommendations
The results indicate that the raw materials production phase and the mixture mixing phase contribute to the most GHG emissions for the asphalt mixture course. Whether considering the cement production or not, the raw materials production phase contributes to the most GHG emissions for the cement stabilized aggregate courses. The use of raw materials with low GHG emissions and increasing the efficiency of asphalt mixing equipment are good starting points to reduce energy consumption and GHG emissions. The warm/cold asphalt mixture can be helpful to decrease the GHG emissions thanks to a lower mixing temperature. In addition, emulsion asphalt could be a good choice to reduce the environmental impact. The benefit of using reclaimed asphalt pavement (RAP) is the reduced extraction and production of virgin aggregates.
On April 8th, 1970, a huge gas explosion occurred at the site of construction for elongation of Osaka city subway line No.2 (Tanimachi line). The gas was leaked out of a detached joint for a drainer on the medium pressure piping, which was under construction for suspension. The gas was filled in the tunnel, ignited, and exploded violently creating a fire pillar of over 10m in height, and causing cover plates over to scatter over an area 200m in length (Figures 1, 2, and 3). The explosion resulted in a terrible accident (so-called Tenroku gas explosion accident), with 79 persons dead, 420 persons injured and 495 houses and buildings burned and destroyed. Almost all of the victims were bystanders having no direct relation to the construction work. The causes of the accident were believed to be a decrease of the joint strength by the weight of passing traffic vehicles together with the influences of the construction work itself. Furthermore, no measures were taken against drawing off the joints. Because most of victims were bystanders, this accident had a large social influence, and it left various precepts as a municipal disaster that was produced by the tremendous boom of municipal development in an age of high economic growth.
4.1. Case Study
Using the above inventory analysis results, a case study is carried out on a typical Portland cement concrete pavement of the expressway in the west of China, Shaanxi Province. There are two lanes in each direction, making four lanes in total. The length is 15.2 km, and its width of the subgrade is 28 m. The thickness of the cement concrete pavement layer is 0.26 m. The schematic diagram of the concrete pavement is shown in Figure 2. Additionally, the width of the cement pavement surface is 11.75 m in each direction, which is divided into 4.5 m, 3.75 m, and 3.5 m by the longitudinal joint. The length of each concrete slab is 5.0 m. Transverse shrinkage joints adopt orthorhombic cutting joints which are equipped with steel dowels. Longitudinal shrinkage joints and construction joints are equipped with tie bars. The concrete mix design is a ratio of water to cement of 0.39, the amount of cement is 385 kg/m 3 , the amount of sand is 671 kg/m 3 , the amount of coarse aggregate is 1194 kg/m 3 , the mass ratio of superplasticizers is 0.4%. The transportation distance from the concrete plant to the construction site is an average of 10 km. Ready-mixed concrete is transported by a medium heavy truck.
A risk may or may not happen. This inherently probable uncertainty cannot be eliminated, but it can be made little clearer by clarifying the probability of occurrence of the risk, to get a better understanding of the consequences and alternatives if the risk occurs and determine the factors that influence the magnitude and likelihood of occurrence of the particular risk. This means that an uncertainty can never be completely eliminated, but it can be reduced to a level the project find tolerable. The authors of this paper have reviewed the literature on construction risk management that has been published in ten selected top quality journals from 1983 to 2015, It has been found that risk research, as applied in construction management discipline in the past three decades, can be divided into six broad fields, encompassing: (1) Risk Identifications; (2) Risk Approaches; (3) Risk Methods; (4) Risk Measurements; (5) Risk Integrations and (6) Risk Improvements (Fig. 2).
Material waste in construction contributes approximately 30-35% of project cost; thus leading to material loss and project cost overruns. Lack of concern by Governments and developers globally and Nigeria, in particular, is continuously affecting the use of these resource materials. The aim of this paper is to examine the ways by which construction material resources can be optimised towards sustainable material resource preservation. Questionnaire method has been used, and administered among construction consultants in Nigerian. A total of 70 questionnaires were administered to construction practitioners; 53 were returned giving a 75% response rate. This was analysed using descriptive statistics. The findings reveal that selection of low-quality products and inexperience of method are the major sources of material wastage at the design stage. Construction stage major sources of material wastage are design changes during construction and re-working due to incorrect use of material and labour. While at procurement stage the major source of materials waste are the lack of possibility to order small quantity and waste encountered during loading/transportation. Finally, at the handling stage, the major sources of material wastage are theft and inappropriate storage. The study also revealed that lack of adequate security in the country and inadequate knowledge of recycling are the main challenges that occur more frequently in resources management .The study found that the following factors should be considered for sustainable material resources optimisation that include, use of standard space product design, adoption of supply chain management, and developing of material schedule software. It recommends that better utilization of resources through adopting lean production and prefabricated component processes, use of appropriate equipment and specification, recycling/re-using of old materials for new construction projects will assist greatly to reducing visit of the base materials, hence leading to resource optimization and protection of the environment. Lastly, there is the need for policy establishment and implementation for resource optimisation for the Nigeria construction industry
e) It shall be mandatory for all buried pipelines to be protected against corrosion and where any pipeline is to transport corrosive or toxic gas, then the design parameter shall be such that the gas pressure at any time in the pipeline shall not result in a hoop stress greater than 60 percent of the specified minimum yield strength of the pipeline material based on the nominal wall thickness. Also, block valves and check valves for such pipelines shall be so located as to prevent the escape of the corrosive or toxic gas into the atmosphere in the event of a pipeline failure.
range of industrial fields such as aircraft, automotive and medical devices for the appli- cation of functional coatings e.g. anti-bacterial, anti-scratch, anti-reflection and en- hance wear resistance    . Within the PECVD process the substrate allocated in a vacuum chamber is exposed to the influence of the plasma. To create the functional coatings precursor gases are feed into the process zone where they are fragmented by the plasma. Those fragments are able to react and form a thin film on a substrate posi- tioned in or near to the plasma. Hence, the plasma polymerization and the resulting coating strongly depend on the PECVD process parameters such as the chemistry of the precursor gases as well as the chamber operational characteristics. According to the operational conditions one precursor gas can lead to a variety of films, and thus a pre- cursor with a particular chemical structure will not necessarily result in a desired plas- ma polymer . Nevertheless, the PECVD process parameters can be successfully tai- lored to achieve the aimed coating properties. Noborisaka and coauthors  reported for example on the importance of the selection of the right precursor gas mixture for the coating formation. The appropriate mixture ratio of the precursor gases trimethyl- silane and oxygen (TMS and O 2 ) was investigated to obtain polycarbonate films as al-
Although road construction and use provides significant economic and social benefits, its environmental impact is of growing concern. Roads are one of the greatest greenhouse gas contributors, both directly through fossil energy consumed in mining, transporting, earthworks and paving work, plus the emissions from road use by vehicles. Globally, the distance covered by roads is more than 34 million km (International Road Federation 2010), nearly 90 times the distance from the Earth to the Moon. Each kilometre of road constructed requires large quantities of rock, concrete, asphalt and steel to be sourced, transported and placed. A typical two-lane bitumen road with an aggregate base can require up to 25,000 tonnes of material a kilometre, showing why aggregates are the most mined resource in the world. (The Future of Roads | Sustainable Built Environment Nov. 2011).
The construction of the gas pipeline requires the removal of vegetation from the whole area for the works. Due to the linear character of the in- vestment, this area is a strip of length equal to the length of the gas pipeline and its width depend- ing on its diameter – the width of the mounting area was about 33 m (Environmental impact re- port..., 2014). Vegetation outside this area should not have been affected by the construction. The situation where a pipeline in the ground interferes with the migration of groundwater may be an ex- ception. In this case, the vegetation outside the as- sembly belt may be weakened or the composition of the community may be reduced. During the construction work, the deeper layers of the earth may be formed within the mounting belt. In such places, hypoxia in heavy soils and excessive me- chanical resistance to medium and light constitute the limiting factor for plant yield.
However, the Niger Delta is known and recognized globally not for the rich biological diversity but for its non-renewable oil and gas resources. The region is home to the hydrocarbon exploration and production activi- ties in Nigeria where proceeds from this singular industry (i.e., oil and gas) accounts for over 90% of the na- tion’s total export earnings . With proven crude oil reserve of 37.2 billion barrels, 165 trillion standard cubic feet (scf) of natural gas, 75.4 trillion scf of non associated gas and average of 2.28 million barrels of crude oil production per day, Nigeria is Africa’s largest crude oil producer, the world’s 11th largest producer as well as 8th largest exporter 2011 . Nigeria has been exporting crude oil from this region since 1958. Effective oil and gas exploration and production has therefore taken place in this region described as environmentally sensitive
Monitoring construction resources used in road/bridge projects, such as heavy equipment, enables not only improvements in productivity but also increased knowledge of emissions produced as a result of fuel consumption. Previous studies conducted by the United States Environmental Protection Agency (EPA) have demonstrated that heavy-duty construction equipment is one of the major contributors of emissions from diesel engines. Diesel engine emissions contain large amounts of carbon monoxide (CO), nitrogen oxides (NOx), hydrocarbons (HC), and particulate matter (PM), all of which have direct negative impacts on human health. A practical way to cut emissions is to reduce the time that construction equipment spends doing non-value-adding activities and/or idling. Recent research in automated equipment monitoring using sensors and Internet-of-Things (IoT) frameworks have leveraged machine learning algorithms to predict the behavior of tracked entities. Previous methodologies, however, depended on manual feature engineering, and were therefore not completely conducive to fully automated, generalizable applications. The advent of deep learning models not only automated the feature extraction step, but also resulted in higher accuracies compared to the performance of traditional and shallow machine-learning methods.
Figure 7-11: The Relationship of RSS Distribution between Two Different RFID Tags at the Same Place
(4) Results and discussions for experiment two
A summarised table for all the tests done for site logistic tracking is provided in Table 7-5. The researcher collected the RSS data of each RFID tags on the module. The sampling rate was 3-8 seconds per RSS record. 16 tags with known locations were treated as reference tags for calibration. Similar calibration research had been conducted by Razavi and Haas (2011). Compared to the true positions identified through survey technologies, the positioning errors of static RFID tags through RSS data with reference tags calibration are illustrated in Figure 7-12. Among these 7 tags attached to the module, the errors can be controlled within 3 meters, which suggests that using the active RFID system was capable of tracking non-line-of-sight activities such as knowing where the multiple construction resources were in a relativity large- scale LNG plant construction site. In addition, site managers could easily discover the objects of interest and request field workers to locate it in a short duration. This is because the search range has been narrowed down to a 3-meter radius circle. In cooperation with scanners through the passive RFID technologies, field workers were easily able to identify the necessary targets
Among these features, the one should be noted that characterizes the future of karst processes development through space and time: the aggressiveness of natural waters. Since this feature describes the "behavior" and the intensity of the process in whole, the assessment on its base will be promising not only at the design stage, but also during the main gas pipeline maintenance. Under natural conditions, the system "water - rock" has equilibrium-nonequilibrium character. In this case, water, irrespectively of depth and speed, is always in nonequilibrium with some minerals by dissolving them, but is in equilibrium with others by generating them. Great contribution to the study of this process was made by the American researchers R M Garrels and Ch L Kraist.