Preparation And Characteristics Evaluation Of Swellable Profile Control Agent

In the mid- and late period of water flooding in oil-field, the stratums are not homogeneous, so the water flows along the high penetrated stratums. The problems are high water cut, early submerging, low extent of water spreading into mid-low penetrated stratums and low oil output. If we deal with the water-absorbing section of water well, the oil output can increase. The volume swellable profile control agent is a main type profile control agent in oil-field. As it is easily to operating and the technique is simple, it is used more and more widely in national oil-fields. But there are some problems such as fail in profile control in water-well, short period of output increasing,etc. The reason is that is shortage research in profile control theories of this product, technics of operating and performance testing. The evaluate parametes of agent performance which are used commonly are water-absorbing index and simulant blocking rate. But the more important parametes such as strength and heat stability are not in research systemically. In this paper, a simple, good repeat method in research strength and heat stability is raised. And some researchs have been done like that how the producing indexs (stuffing, crosslink agent, sodium carbonate, initiator)to influence strength and heat stability.Aim to the character of sandstone stratums in Daqing oil-field and the costs of profile control agent producing, we have done some modification in producing direction, and done the research how the producing indexs to influence the water-absorbing parameter. When the stuffing increasing, sodium caebonate decrease and initiator decrease, the water-absorbing decrease gradually. The stuffing is the main influence parameter. The ratio of calcium carbonate and bentonite has no influence to water-absorbing in my general texts.According to the deplugging technique of polymer gel blocking-off, we find a way to evaluate the heat stability. Under the condition of 0.8wt% chlorine dioxide and 90℃water bath, being activized by citric acid with 0.03 weight ratio(citric acid to chlorine dioxide), chlorine dioxide can better break the profile control agent samples. This method is short time taking, safety and good repeat. The quantity of stuffing doeslittle influence to the heat stability. When the crosslink increase, sodium carbonate decrease and initiator increase, the heat stability of agent will be increase. The crosslink do more influence. The ratio of calcium carbonate and bentonite has no influence to heat stability in a suit range. When the value of ratio over 3:2, the heat stability decrease rapidly.A self-produce set which simulate the cranny of stratums is used to measure the strength of profile control agent. Using this method, we can divide the agents into two types: easy to break and easy to distort. Using line fitting to analyse the mechanical data, we can use the b value to measure the strength of agent easy to break. Using exponential functions fitting to analyse the mechanical data, we can use the y0 value to measure the rigidity and using Ae xtto measure the tenacity of agent easy to distort. So we can measure the strength of the agent easy to distort synthetically.For optimized high water-absobing formula: 0.005g N,N'-methylene bis-acylamide cross linking agent, 0.05g potassium persulfate and 0.05 sodium sulfite as initiating agent, 10g AM, 10g bentonite, 0.6g sodium carbonate, water 40mL, the rate of water-absorbing can reach 101.45. For optimized good heat stability formula: 0.1g N,N'-methylene-bis-acylamide cross-linking agent, 1.6g potassium persulfate and 1.92 sodium sulfite as initiating agent, 50.0g acylamide, 100g bentonite, 5.0g sodium carbonate, water 200mL. For optimized high strength formula: 0.04g N,N'-methylene bis-acylamide cross linking agent, 0.65g potassium persulfate and 0.65g sodium sulfite as initiating agent, 50.0g acylamide, 25g bentonite, 25g calcium carbonate, 1.0g sodium carbonate, 150mL water.Give some advices to improve the technics in mixing, polymerization, prilling, drying and milling and take some advanced machines to the industry production.