Tubing Dimension Optimization for the Development of an Offshore Gasfield

L1 is one of the largest offshore gas fields currently under development.In order to optimize the related design,nodal analysis is applied(including proper consideration of the plant productivity,sensitivity to the tubing size,erosion effects,liquid carrying performance,and tubing string).As a result of such approach,it is shown that 13Cr material should be chosen as the appropriate tubing material.Moreover,3-1/2 inches 9.3 lb/ft N80 tubing,4-1/2 inches 12.75 lb/ft N80 tubing,5-1/2 inches 17 lb/ft N80 tubing should be used for a gas production rate under 80×10^(4)m^(3)/d,between 80×10^(4)m^(3)/d and 120×10^(4)m^(3)/d and above 120×10^(4)m^(3)/d,respectively.

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.

A Case of Multi-Stage Fracturing Horizontal Well Used in BZ Oilfield in Bohai Bay Low-Permeability Oilfield Development

BZ oilfield in Bohai Bay of China was a typical offshore low permeability oilfield, which was restricted by many factors such as environment and economy. In this paper, the development characteristics of BZ oilfield were summarized in depth, and the new development mode of offshore low-permeability oilfield was explored from reservoir prediction, well spacing and fracturing technology. Taking BZ oilfield as an example, a set of technical system for the effective development of offshore low permeability oilfield had been formed through research, which mainly includes reservoir prediction and evaluation of offshore middle and deep low permeability oilfield, optimization of horizontal well pattern, multi-stage fracturing design of horizontal well and other technologies. The results show that improving the resolution of seismic data, strengthening the analysis of seismic reflection characteristics and carrying out the comprehensive study of seismic geology were the keys to solve the reservoir prediction of offshore low-permeability oil fields. Multi-stage fracturing horizontal well pattern is the main pattern of offshore low-permeability oilfield development. The parameters of multi-stage fracturing horizontal well together affect the development effect. Selecting the optimal fractured horizontal well pattern can greatly improve the development effect. The successful combination and application of new technology system was the foundation and core of conquering offshore low-permeability oil fields. On the basis of understanding the geological characteristics of oil reservoirs, it is an effective means of developing offshore low-permeability oil fields by selecting reasonable production methods, well types and well patterns. Using efficient perforation and fracturing technology to successfully control fracture parameters and form optimal injection and production well pattern was the key to improve low permeability offshore oil fields.

Utilizing Dynamic Data to Quickly Evaluate Advantageous Channels and Applications

In response to the high cost and difficulty of high-speed development and testing data in offshore oil fields, this paper proposes to use the most easily available production performance data as the basis and use the grey correlation method to calculate the correlation coefficient between oil and water wells to characterize the degree of development of advantageous channels. The consistency between the calculated results of this method and the tracer test results is over 80%. Based on the fitting results, the correlation coefficient exceeds 0.74 to determine the existence of an advantageous channel. According to the research results of grey correlation method, Bohai K oilfield has completed the combined profile control and flooding measures, and the daily oil production has increased by 20 m3/d. This method is simple, fast, and can achieve quantitative evaluation, which saves time and investment compared to offshore testing. It has strong application and reference value for the development of other offshore water injection oilfields.

Energy Consumption Analysis and Optimization of Electric Submersible Pump System

Electric submersible pumps account for a considerable proportion in the development of the Bohai Oilfield. Improving the system efficiency of the electric submersible pump wells, ensuring that the units operate in the high-efficiency zone, is essential. Analysis shows that the efficiency of the electric submersible pump system depends on the wear and tear of each component of the submersible pump equipment, the setting of operational parameters, and more importantly, the production status and daily management level of the oil well. Therefore, improving the structural performance of the submersible pump product, optimizing the parameters setting of the oil well, strengthening daily management, establishing a scientific management system, and improving the production management process and system can effectively improve the production efficiency and economic benefits of the oil well, and further achieve the goal of energy saving and emission reduction. In addition, it is necessary to actively promote the concept and technology of energy saving and emission reduction, encourage oilfield enterprises to explore effective measures to reduce the energy consumption of the electric submersible pump system by strengthening the scientific management system, and achieve a green, low-carbon, and high-quality development of oilfield production to achieve the unity of economic benefits, social benefits, and environmental benefits. This article applies the above measures in the P oilfield to achieve energy optimization of submersible electric pump systems, reducing the daily power consumption of single well submersible electric pump systems by 371 kWh per day, increasing the submersible electric pump's lifespan by 200 days, generating considerable project benefits.

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.