Reseach On Selective Water Shutoff And Acidizing Technology In Steam Huff-Puff Heavy Oil Wells

There are two major problems in heavy oil blocks of Jinzhou oil production of Liaohe Oilfield. One is heavily watered, the other is lack of exploiting potentialities. This paper studies the new selective water shutoff and acidification technology for heavy oil stimulation well, effectively block high water channels, and lift the low permeability layer clogging contaminants, restore or increase permeability of low permeability, liberate the production capacity of low permeability layers.First we choose the best formula of acid liquid. We chose the best ratio of acid species according to the oil physics, reservoir characteristics, and the result of core powder dissolution test. Also, we screen experiment of clay stabilizer additive through corrosion test, ferric ion stabilizer screening and then we get the final formula of acid liquid. Based on the acid formula, we secondly make an emulsified oil type plugging agent. According to the experiment, it has good acid resistance, reach the standard of construction site. Also, if it is used under the condition of 60% water content, the after water recovery is increased by 16.22%, reach the best plugging effect. Third, we modify the existing oil soluble substances(such as paraffin wax, bitumen, oil soluble resin), change the drug preference ratio to control the molecular structure, improve oil solubility, increase strength, improve acid resistance, and deployment a new oil soluble plugging agent which can be matched with the pore throat size.We research on the selective water blocking and acidification physical simulation experiment using the selected acid which combines two kinds of acid plgging agent. Through the core and parallel to the parallel core water plugging acidification experiment, we measure the changes of pressure and recovery rate, the acid resistant performance, the plugging rate, the valid date and the compatibility, get reasonable injection parameters, evaluate the selective plugging water acidification ability. The experimental data shows that the plugging rate and blocking rate differ according to the difference of permeability parallel displacement injection oil soluble plugging agent and acid mixture. When the core permeability gets higher, the oil reservoir plugging effect gets better, while the water plugging effect gets poorer. The average oil reservoir plugging rate is 53.46-72.67%, the average water plugging rate is 64.1-80.7%. In the mean time, when the parallel cores of different permeability displacement are injected intoemulsified oil acid type water plugging agent, the average oil reservoir plugging rate is 35.99-50.47%, the average water plugging rate is 25.1-52.73%. From these data, we come to the conclusion that selective plugging acidizing plugging agent of oil soluble plugging agent is better than the emulsified oil acid type water plugging agent.