Sand Nian Oilfield Injection Water Quality Evaluation Index And Optimization

Generally, water flooding in Oilfield is a more effective method to exploration all over the world. Aim to maintain the energy of reservoir and obtain more oil, it becomes a key problem how we can inject well and enough water for many researchers studying oilfield development. However, in water flooding water quality influences the water injection rate and the effect of water flooding directly. If water quality mismatch to the characteristics of reservoir, the cake will build up on inlet and in the reservoir so that it results worse connectivity even pore constriction plugged. As a result, the reservoir absorbing capacity decreases and injection pressure increases. Beside, in bad characteristics reservoir, it will make heterogeneity various and oil displacement area small, so the energy become shortage and production decrease finally. To sum up, evaluation of injection water quality and optimization design of indexes is important for reservoir development.There are many factors of reservoir damage and absorbing capacity descendent, and the mechanism is complicated, so evaluation of injection water quality and optimization design of indexes is a complicate subject. This paper analyzes the theory of absorbing capacity descendent resulting from water quality problem during water flooding, obtains feasible evaluation model, and optimizes the indexes of water quality on the basis of analysis. First, the mechanism includes four kinds, mechanical function, chemical function, biological function and heat function. Then according to the theory of absorbing capacity evaluation, it explains the common evaluation model, B&D model, VVL model, Sharma model, Dynamics model, DBF model, VBD model and compound model, and prepare water absorption capability evaluation program. Next it evaluates the field data of some block in Shanian Oilfield using former program. After analyzing the data, it concludes the relationship between the damage degree and water quality indexes and regression model. Then matching the result of model with field data gets the same change trend. Lastly taking the method of experiment in lab, it optimizes the indexes of water quality, such as suspended solid diameter and concentration and oil droplet concentration, evaluates the relationship between the indexes using Design-Expert program, and takes the experiment to show the better one.The feasible program of absorption capacity evaluation and optimization design of water quality is on the basis of theory and experiment researching. Beside, the theory model of suspended solid diameter and concentration and oil droplet concentration is useful in reservoir injection. The evaluation method and optimization design has value to the theoretical and practical application. The way of researching is clear, the means is feasible, and this method has value to evaluation of injection water quality and optimization design of indexes in water flooding of oilfield.