Research And Application Of Improving Surface Water Injection System Efficiency In Huabei Oilfield

Water injection is the major production mode in onshore oilfield. It can effectively supplement the formation energy and enhance oil recovery. Most of the oilfields in China are using artificial water injection to maintain reservoir pressure. Water injection to stratum plays a very important role in guarantying a high and stable production. It makes oilfield water injection system become an important part of the production system.Oilfield water injection system is energy-hungry, especially with the oilfield development to enter the high water period, more and more water is needed with the increasing of the injection pressure, so energy consumption in water system is also growing rapidly. According to statistics, the energy consumption of water injection system accounts for about one-third of the total electricity consumption in oil production. At present, the oilfield water injection system efficiency is relatively low. Water system efficiency in PetroChina is about 47.8%. Generally, the energy utilization rate is not high. Therefore, improving the efficiency of water injection system and cutting energy consumption are of great practical significance.In this paper, based on the efficiency of water injection system field tests, efficiency calculations, pipe network analysis, according to the optimization theory of the coordination of supply and demand of the source nodes and the destination nodes, a series of key technologies were solved, such as the mathematical model of the characteristics of reciprocating pump station on the base of theoretical analysis of the system identification and parameter estimation, the influence of the injection process parameters, equipment operation and structure parameters on the water injection system operating conditions, the analysis of the efficiency region of water injection system, the establishment of the working condition diagnosis model of a water injection system. The corresponding injection system optimization methods were made with the actual situation of different water injection system in Huabei Oilfield. A series of adjustment and reform programs of water injection system have been developed. Based on the analysis of water injection system, an integrated evaluation method of the water injection system was established.After the application in six oil and gas production units in Huabei Oilfield, especially in the water injection system adjustment of Bieguzhuang oilfields and Liu 17 fault block, remarkable effect has been achieved. Injection efficiency of the system increased by an average of 3.8% and water injection consumption per unit fell by an average of 0.92kW.h/m3. Total economic efficiency has reached 6.08 million Yuan.