| There is mostly continental sediment in domestic oilfields, and the majority of oil reservoirs are composed of several oil-bearing sands. Because of the discrepancy in reservoir sedimentary environment, there are some contradictions in stratification plane, inlayer and interlayer. The injected water goes ahead abruptly along in high permeable reservoir during water flooding, which will lead to the water out happen too early. The phenomenon is especially severe when the reservoir enters into the high water cut period, it will affect holistic development effect. So, we take some effective and reasonable measures to adjust water injection profile, it has important realistic significance to improve water flooding, polymer flooding effect and promote a long term high yield and stable production.This paper entirely expatiates upon the categories and types of the profile control agents and the water shutoff agents that are used oilfields in home and abroad, and concludes the performances and characteristics of six categories (about 70 kinds) profile control agent and the water shutoff agent. This paper also depicts the development situation of domestic oilfield's profile control agents and the water shutoff agents. It is concluded as follows: domestic oilfields began to research and apply water plugging and profile control techniques in the 1950s, up to the present, it generally experienced three development stages, that is to say, the stage mainly composed of machinery (1950s-1970s), the stage mainly composed of chemical agents (started from the early 1980s), profile control of single well and block integral comprehensive treatment stage (started from the mid of 1980s). From 1979 to 1996, there are 2×104 times field trials and application operations in domestic oilfields, which improve the water flooding development effect, and increase the recoverable reserves of crude oil and oil producing capacity and decrease the water production rate, at the same time , there are an obvious economic benefit and social benefit.This paper aims at the problem that exists in the property evaluation methods aspect of oilfield cross-linked polymer gel system. We proceed all sided and systemic research into the property of Al3+ cross-linked polymer gel, Cr3+ cross-linked polymer gel and composite ion cross-linked polymer gel making use of the indoor experiment method.For the polymer gel cross-linked by trivalent aluminium (Al3+), the testing results of the cross-linked polymer solution viscosity, resistance factor, residual resistance factor and rheological behaviors show that the cross-linked polymer solution made by produced water has low viscosity, property characteristics of high residual resistance factor and is larger than resistance factor after cross-linking reaction happened between the polymer molecules or inside the polymer molecule. The cross-linked polymer solution can flow in the porous medium, but compared with common polymer solution, the flow ability of cross-linked polymer solution is worse. The cross-linked polymer solution's flow resistance is big, it enters into the high permeability zone, which makes the sequent liquid enters into middle and low permeability zone, thus, sweep volume is enlarged and recovery efficiency is enhanced. The resistance factor, residual resistance factor and rheological behaviors can be act as the basic sieving indexes of directions for producing cross-linked polymer solution.For the trivalent chromium (Cr3+) cross-linked polymer gel, the research results of this paper show that under the produced water of the No. 2 oil production plant of Daqing oilfield, trivalent chromium(Cr3+)and organic cross-linking agent both can make cross-linking reaction of polyacrylamide molecules happen, and polymer cross-linking micro-gel forms. The cross-linking reaction speed of trivalent chromium(Cr3+)cross-linking agent is fast, the incremental value of viscosity of polymer solution is big after cross-linking. The crossing reaction speed between organic cross-linking agent and polymer is... |
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