Loose Sandstone Conventional Heavy Oil Reservoir Moderate Sand Increase Productivity Of Basic Research

Sand production becomes a growing concern to more and more petroleum engineers. On the one hand, it will bring a lot of production troubles, such as the erosion of pipelines, plugging, oil zone buried by produced sand, and dealing with the produced sand, which costs billions of dollars each year. On the other hand, producing with limited sand in unconsolidated sand reservoir will enhance the oil rate and lower the costs of sand proof. Based on the detailed analysis of sand production while producing, a new method-producing with controlled sand in unconsolidated sand reservoir was presented, say, according to the facts of reservoir and the target, we can produce with limited sand by controlling the sand rate and other producing parameters.In order to maximize the profits of producing with limited sand, the following items are the concerns. It is necessary to study the characteristics, the mechanism of improving production rate about sand production. The onset of sand production, the sand rate and the relationship between production rate and sand rate should be predicted and they are the basis for decision making of producing with controlled sand.During the research, the past methods used to predict the onset of sand production, the prediction of sand rate and the quantitative relationship between the sand rate and production rate was discovered some wrong. It results from the theory of Terzaghi effective stress the past researchers used. By using the double effective stress, the difference between the prediction data and real data is minimized and it explained the reasons of the difference between them.Based on the above study, the following conclusions were achieved:Through comparing the methods of sand proof and cold production with sand, a new method—producing with limited sand was formed and presented here. This method is suitable to heavy oil reservoirs in unconsolidated rock and will benefit from the both methods of sand proof and cold production.In order to make the method of producing with limited sand more acceptable and practicable, this paper analyzed the mechanisms sand production, the characteristics of producing with sand and the factors which plays a role in sand production, and the aspects that enhance the production rate while producing with sand in detail.This paper proposed to predict the onset of sand production by using double effective stress and we demonstrate the structural effective stress is more suitable forpredicting the onset of sand production, and derived the formulae that used to predict the onset of sand production due to shear failure of wellbore(perforation tunnel), perforation tip.The analytical model used to predict quantitatively the effect of sand production on the production rate was derived, and it can be used to make the decision of producing with limited sand.The past coupled model used in reservoir engineering was modified by applying the primary effective stress and the finite element formulae of this model were achieved. Based on this coupled model, the immiscible sand and liquid flowing model used to predict quantitatively the rate of sand and oil was derived and built The results calculated from the modified model were demonstrated more reasonable.This paper analyzed in detail the characteristics of producing with sand, the factors which affect sand production and the mechanism of production rate enhancement due to sand production. Based on the above-mentioned research, a new method which allows limited sand production is presented. The basic research on putting the method of producing with limited sand into practice was carried out, such as the prediction of the onset of sand production, the quantitative relationship of the sand rate and production rate. The conclusions achieved in this paper are the basis for making the method of producing with limited sand in unconsolidated sand rock reservoirs, and more research should be furthered such as the reasonable limit of sand rate, when and how to begin sand proof, how to determine the parameters and the related research about producing with limited sand.