Crack Reservoir Deep Profile Technology Research And Application

For Panguliang Chang-6 Reservoir in Changqing Oil Field charactered by low-permeability fractures, this paper researched the growth actuality and regulations of fractures, and analyzed water-flooding status and the reasons of producing water. On the basis of summarizing the successes and failures measures of keeping stable production in past years, this paper put forward pertinent technologic measures of keeping stable production——compound in-depth profile modification technology of pre-crosslinked particle/ water-flooding flow direction alteration agent/associated polymer gel. We developed compound in-depth profile modification system of pre-crosslinked particle/ water-flooding flow direction alteration agent/associated polymer gel suitable for this reservoir and carried through systematic evaluation for the application property of the profile modification system. The research indicated that pre-crosslinked particle and water-flooding flow direction alteration agent had the merits of high expanding times, good anti-temperature and anti-salinity property, distinct potential of EOR, and could make the flow direction of injection water alter effectively as well as advance swept efficiency. We obtained the formulations of associated polymer gel systems which can advance swept efficiency and displacement efficiency obviously. This paper also researched compound in-depth profile modification mechanisms of pre-crosslinked particle/water-flooding flow direction alteration agent/associated polymer gel. We researched optimized decision theory and model of in-depth profile modification, and worked out optimized decision programme to decide volume of profile modification agent and forecast plugging radius as well as evaluate profile modification effect so as to make field application more scientific. On the basis of these researches, we carried operation scheme design of in-depth profile modification for injection and production well groups. Through field application, we obtained obvious oil-increase effect. The achievement established firm theory foundation for the research and field application of water-control and oil-increase technology of low-permeability fractured reservoir, and accumulated abundant practice experiences, so it had important theory and spread application value.The achievements of this paper were as follows:(1)The traits of physical property of reservoir and the growth actuality and regulations of fractures were researched and analysed. On the basis of the development actuality of oil field, the water-flooding status and the reasons of producing water as well as the harm mechanisms of water to the reservoir were researched and analyzed. We put forward ideal method of EOR——compound in-depth profile modification technology.(2) The property of in-depth profile modification system of pre-crosslinked particle and water-flooding flow direction alteration agent as well as the matching low between particles and the size of pores were researched in the laboratory. The result indicated that the main function of this system is"in-depth profile modification"and it could plug channels producing water in big fractures to make injection water alter flow direction and enhance sweep efficiency obviously.(3)The formulations of in-depth profile modification agent of associated polymer gel suitable for the high salinity reservoir were as follows: the concentration of associated polymer 3500 mg/L, the concentration of organic chrome cross-linked agent 130 mg/L, the concentration of retardant 50 mg/L, the concentration of deoxidant 90 mg/L, the concentration of formaldehyde 0.185%. The gelation reaction mechanism of block agent were researched. The property of the associated polymer gel was evaluated. The intensity of hydrophobically associated polymer was medium and could give play to"modification"and"drive"as well as displace oil in medium or small fractures effectively.(4) The in-depth profile modification mechanisms of compound deep system of pre-crosslinked particle/ water-flooding flow direction alteration agent/associated polymer gel were researched.(5) The application of Tracer Monitoring Method in Panguliang Reservoir were researched. On the basis of the combination of the formulations of block agent and the reservoir, we researched optimized decision method of in-depth profile modification, and worked out optimized decision programme. We could use it to select wells groups which need profile modification, decide volume of block agent, forecast plugging radius and evaluate or forecast effect of profile modification.(6)The operation scheme and test effect of in-depth profile modification were researched and analyzed. The rationality of scheme and technics were analyzed and the existing problems as well as technologic measures were discussed.