Research On In-depth Profile Agent In The Block Bao-14 Of Ke-er-qin Oilfield

Weak gel has been widely applied to enhance oil recovery in deep reservoir inrecent years. In this paper, based on the conditions of the Block Bao-14 reservoir ofKe-er-qin oilfield, we choose the optimum in-depth profile agent which is inaccordance with the crack and low-permeability feature. We also research the weakgel performance and the affecting factors, so we put forward the in-situ appliedingredient of the Block Bao-14 reservoir of Ke-er-qin oilfield. Physical simulationalso has been used to research on the selective weak gel migration conditions andperformance of infusion and sealing characteristics along with injection pressure,polymer concentration, and injection parameters separately. In this paper the objectiveof the research is to find an optimum in-depth profile agent which is in accordancewith the reservoir situations and to evaluate the in-situ application probability of theweak gel.According to experimental study and theoretical analysis, the main achievementsin this paper are as follows:1. Based on the Block Bao-14 reservoir injection well and produced water, wechoose the multiple profile modification system of HPAM-phonelic aldehydecross-linking weak gel and volume expansion grains as the in-depth profile agent. TheHPAM-phonelic aldehyde cross-linking weak gel is composed of HPAM, JB, TJL andTJC, in which the concentration of HPAM is 0.07%～0.3% for becoming the steadyweak gel. The in-situ applied ingredients include: HPAM concentration is 0.2%, JBconcentration is 600ppm, TJL concentration is 150ppm, TJC concentration is about300ppm and the volume expansion gel grains 2~5mm in diameter and concentration0.2%.2. The initial forming-gel time of the cross-linking system is 2~10 hours at 30～50 ℃ under the recommended ingredients and the intensity G of weak gel is0.5~2.5Pa. The cost of the in-depth profile agent is not beyond 200 RMB/m3.3. The neutral and weak alkaline conditions are beneficial for forming the weakgel. The intensity and time are satisfied with the in-situ application conditions, as wellas the long-term stability is good.4. The total salinity of the injection water and the produced water in BlockBao-14 reservoir is very low, so there is little influence on forming the weak gel forthe profile modification agent.5. The artificial core simulation experiment shows that the complicate profilemodification system is applicable for the crack, high porosity and high permeabilityfeature of Block Bao-14 reservoir.6. The application of the complicate profile modification system composed of thevolume expansion grains and cross-linking polymer weak gel, not only improves thein-depth injection capability of the volume expansion grains, but also enhances thesealing capability of the weak gel and grains. Compared with the low effectiveness ofsingle application with the weak gel or the volume expansion grains, the complicateprofile modification system can acquire the better sealing effect to the crack, highporosity and high permeability reservoir.