MECHANICAL PROPERTIES OF LONGITUDINAL SUBMERGED ARC WELDED STEEL PIPES USED FOR GAS PIPELINE OF OFFSHORE OIL

Since the development of offshore oil and gas, increased submarine oil and gas pipelines were installed. All the early steel pipes of submarine pipelines depended on importing because of the strict requirements of comprehensive properties, such as, anti-corrosion, resistance to pressure and so on. To research and develop domes- tic steel pipes used for the submarine pipeline, the Longitudinal-seam Submerged Arc Welded （LSAW） pipes were made of steel plates cut from leveled hot rolled coils by both the JCOE and UOE （the forming process in which the plate like the letter “J”, “C”, “0” or “U” shape, then expansion） forming processes. Furthermore, the mechanical properties of the pipe base metal and weld metal were tested, and the results were in accordance with the corresponding pipe specification API SPEC 5L or DNV- OS-FI01, which showed that domestic LSAW pipes could be used for submarine oil and gas pipelines.

Multistring analysis of wellhead movement and uncemented casing strength in offshore oil and gas wells

This paper presents a theoretical method and a finite element method to describe wellhead movement and uncemented casing strength in offshore oil and gas wells.Parameters considered in the theoretical method include operating load during drilling and completion and the temperature field,pressure field and the end effect of pressure during gas production.The finite element method for multistring analysis is developed to simulate random contact between casings.The relevant finite element analysis scheme is also presented according to the actual procedures of drilling,completion and gas production.Finally,field cases are presented and analyzed using the proposed methods.These are four offshore wells in the South China Sea.The calculated wellhead growths during gas production are compared with measured values.The results show that the wellhead subsides during drilling and completion and grows up during gas production.The theoretical and finite element solutions for wellhead growth are in good agreement with measured values and the deviations of calculation are within 10％.The maximum von Mises stress on the uncemented intermediate casing occurs during the running of the oil tube.The maximum von Mises stress on the uncemented production casing,calculated with the theoretical method occurs at removing the blow-out-preventer （BOP） while that calculated with the finite element method occurs at gas production.Finite element solutions for von Mises stress are recommended and the uncemented casings of four wells satisfy strength requirements.

Combined stochastic and discrete simulation to optimise the economics of mixed single-horizontal and multilateral well offshore oil developments

Multilateral wells promise cost savings to oil and fields as they have the potential to reduce overall drilling distances and minimize the number of slots required for the surface facility managing the well.However,drilling a multilateral well does not always increase the flow rate when compared to two single-horizontal wells due to competition in production inside the mother-bore.Here,a holistic approach is proposed to find the optimum balance between single and multilateral wells in an offshore oil development.In so doing,the integrated approach finds the highest Net Present Value(NPV)configuration of the field considering drilling,subsurface,production and financial analysis.The model employs stochastic perturbation and Markov Chain Monte-Carlo methods to solve the global maximising-NPV problem.In addition,a combination of Mixed-Integer Linear Programming(MILP),an improved Dijkstra algorithm and a Levenberg-Marquardt optimiser is proposed to solve the rate allocation problem.With the outcome from this analysis,the model suggests the optimum development including number of multilateral and single horizontal wells that would result in the highest NPV.The results demonstrate the potential for modelling to find the optimal use of petroleum facilities and to assist with planning and decision making.

Analysis of Offshore Oil Pipeline Floating Laying

-Based on the calculation model for the floating laying of the offshore oil pipeline, this paper analyses in detail the internal force, and deformation of the pipeline under a definite structural form (pipeline and buoy) and the way of pulling. The obtained results can be used for the buoy deployment, structure design, and the determination of pulling parameters (the pulling force of the cable and its length, etc.), providing an effective analysis method for floating pipeline-laying. A calculation example is given to show the related calculation process and the main results are analyzed and discussed.

Mechanics of a Grip System of Three-Key-Board Hydraulic Tongs Developed for Offshore Oil Pipe Lines

This paper carries out the analysis of mechanics of a grip system of three-key-board hydraulic tongs developed for offshore oil pipe lines which has been successfully used in oil fields in China. The main improvement of this system is that a lever frame structure is used in the structural design, which reduces greatly the stresses of the major components of the oil pipe tongs. Theoretical analysis and numerical calculation based on thirteen basic equations developed Show that the teeth board of the tongs is not easy to slip as frequently happens to other systems and is of higher reliability.

China Offshore Oil Industry Full of Vigor and Vitality

Since the founding of the ChinaNational Offshore Oil Corporationin 1982, the China offshore oil industryhas parted from closing the country tointernational intercourse and has steadilygone onto the developmental road at highspeed and with high efficiency inaccordance with international practice.In the short time of 13 years, relying onthe correlated policy offered by the stateand the intensification of enterprisemanagement, it has built up a large state-owned enterprise of independentmanagement, self-responsibility forprofits and losses, self-accumulation andself-perfection.

Sinopec Adds Brazil Offshore Oil Reserves with Purchase of Galp Unit Stake

According to Bloomberg on November 12, China Petrochemical Corp., Asia’s biggest ref iner, agreed to buy a 30 percent stake in Galp Energia SGPS SA (GALP)’s Brazilian unit, its second invest- ment in offshore oil fields in Latin America’s largest economy in as many years.

Upgrading, Transforming, and Standardizing of Offshore Oil Drilling Equipment in China

This paper discusses the development of China's oil exploration & drilling equipment, and it focuses mainly on the domestication, industrialization, and standardization of fixed offshore drilling rigs primarily constructed by CNOOC. Considering the manufacturing of and application of deepwater drilling equipment in China, the authors put forward suggestions regarding industry policies and the standardization of China's offshore engineering equipment.

Cooperation in Offshore Oil Deal Set

ＣｏｏｐｅｒａｔｉｏｎｉｎＯｆｆｓｈｏｒｅＯｉｌＤｅａｌＳｅｔＴｈｅＣｈｉｎａＮａｔｉｏｎａｌＯｆｆｓｈｏｒｅＯｉｌＣｏｒｐ．（ＣＮＯＯＣ）ａｐｉｏｎｅｅｒｐｒｏｓｐｅｃｔｏｒｏｆｔｈｅｃｏｕｎｔｒｙ＇ｓｍａｒｉｔｉｍｅｂｏｎａｎｚａ，ｈａｓｅｘｐａ...

Way Offshore Oil Arrives in Nanjing

ＷａｙＯｆｆｓｈｏｒｅＯｉｌＡｒｒｉｖｅｓｉｎＮａｎｊｉｎｇ￥／／Ａｔａｎｋｅｒｃａｒｒｙｉｎｇａｂｏｕｔ３０，０００ｔｏｎｓｏｆｃｒｕｄｅｏｉｌｐｒｏｄｕｃｅｄｂｙａｎｏｉｌｆｉｅｌｄｉｎｔｈｅＳｔｒａｉｔｓｏｆＭａｌａｃｃａ，ｐａｒｔｌｙｏｗｎｅ...

New Headway in China's Offshore Oil Cooperation with Foreign Firms

ＮｅｗＨｅａｄｗａｙｉｎＣｈｉｎａ＇ｓＯｆｆｓｈｏｒｅＯｉｌＣｏｏｐｅｒａｔｉｏｎｗｉｔｈＦｏｒｅｉｇｎＦｉｒｍｓＨｏｕＸｉａｏｙｉｎｇ，（ＣｈｉｎａＮａｔｉｏｎａｌＯｆｆｓｈｏｒｅＯｉｌＣｏｒｐｏｒａｔｉｏｎ）Ｉｎｉｔｓｃｏｏｐｅｒａｔｉｏｎｗｉｔ...

Environmental Impact Assessment Follow-Up of Seismic Survey Offshore Activities in Brazil

Follow-up of environmental impacts is an integral part of the Environmental Impact Assessment (EIA) process, closely related to the effectiveness of the instrument. EIA follow-up has been receiving a lot of interest from scientists and practitioners, though it is recognized as one of the weakest points of EIA systems globally. Also, EIA follow-up is influenced by the context, mainly in terms of the types of projects or activities and their related impacts on the environment. Therefore, the present paper is focused on the investigation of the follow-up stage applied to the activity of seismic survey coupled with offshore oil & gas exploitation in Brazil. Research was based on a qualitative approach that included document analysis and semi-structured interviews with analysts involved in EIA processes, and sought to generate evidence of effectiveness of the EIA follow-up as conducted by the Federal Environment Agency (Ibama) in order to situate the practice of follow-up in the broader context of international best practice principles. Based on the findings, it was concluded that, due to the peculiarities of offshore seismic survey, it is necessary to promote adaptations in the procedures for monitoring impacts in order to ensure proper alignment with the principles and conceptual foundations that guide EIA practice. Specifically, the timing of the execution of the activity imposes challenges for its integration into the “conventional” cycle that has guided the monitoring of the impacts in the EIA of projects.

Integrated generation-transmission expansion planning for offshore oilfield power systems based on genetic Tabu hybrid algorithm

To address the planning issue of offshore oil-field power systems, an integrated generation-transmission expansion planning model is proposed. The outage cost is considered and the genetic Tabu hybrid algorithm(GTHA)is developed to find the optimal solution. With the proposed integrated model, the planning of generators and transmission lines can be worked out simultaneously,which outweighs the disadvantages of separate planning,for instance, unable to consider the influence of power grid during the planning of generation, or insufficient to plan the transmission system without enough information of generation. The integrated planning model takes into account both the outage cost and the shipping cost, which makes the model more practical for offshore oilfield power systems. The planning problem formulated based on the proposed model is a mixed integer nonlinear programming problem of very high computational complexity, which is difficult to solve by regular mathematical methods. A comprehensive optimization method based on GTHA is also developed to search the best solution efficiently.Finally, a case study on the planning of a 50-bus offshore oilfield power system is conducted, and the obtained results fully demonstrate the effectiveness of the presented model and method.

Optimization of the Algorithm for Increasing Injection Rate in Water Injection Wells for Pressure Optimization in P Oilfield

In today’s society, with the continuous growth of energy demand, Bohai Oilfield, as an important offshore oil resource base in China, is facing increasingly severe challenges while contributing to national energy security. In order to improve the quality of water injection in the oilfield and gradually achieve efficient and stable production, Bohai Oilfield has launched a water injection well pressure optimization project, focusing on improving the efficiency and quality of water injection in the water injection wells, in order to achieve the optimal water injection plan. In practical work, P Oilfield continues to promote the development of water injection well pressure optimization projects, emphasizing practical exploration and continuous optimization of work plans. However, during the project implementation process, there were some problems, one of which was that the statistics of cumulative injection volume were not scientific enough, resulting in a more comprehensive and accurate presentation of the actual results of pressure optimization work. In the context of continuous improvement work, after careful analysis and research, P Oilfield has decided to optimize the cumulative injection rate algorithm to guide the oilfield’s water injection work in a more refined way, ensuring sufficient and good water injection, and enhancing the oilfield’s production efficiency and comprehensive competitiveness.