Research Of Reservoir Protection And Reform Measurements Of Low Permeability Oil Reservoir

Now, reserves of low permeability reservoirs take the most part of unused reserves in our country, which take the proportion of 72.8 percent. It is difficult to develop the low permeability reservoirs because of the reasons such as the developing effect and economic benefit is low, reservoir damages is heavy, etc. therefore enhancing the developing effect of low permeability reservoirs will take key affect for sustainable and steady development of our country's petroleum industry through the method of decreaseing reservoir damages and taking effective reservoir stimulation.In this article, the author take Jishan low permeability reservoir as example to discuss the questions below: the origin and the master control factors of low permeability reservoirs, the mechanism of reservoir damages of low permeability reservoirs, the techniques of reservoir protection of low permeability reservoirs and how to stimulate the reservoirs. Through the research , the author recognize the main reasons including low physical property and low natural depletion oil recovery, character of formation damages of low permeability reservoirs, the disconformity of reservoir stimulation techniques which lead to low permeability of reservoirs, the low production of formal well testing and the shortness of production plateau. The main results as follow:1. Rock texture of the principal producing formation of Jishan low permeability reservoir is density, the framework grain outline is not clear, the distribution of intergranular pore is unequal which include macropore and micropore. The porosity of the reservoir alter form middle porosity to low porosity, the permeability alter from low to particular low. The diagenesis which cause the low permeability of reservoir are compaction and cementation.2. mechanism of formation damages of low permeability are not different in essence with which of other porous reservoirs, the damages generally are sold plugging, chemical sensibility, water blocking, scale formation, etc. but the degree of damages of different formation damage are differ because of particularity of reservoir geology and seeping character of the low permeability reservoirs. The research indicate that the reservoir damages of Jishan low permeability reservoir are sold plugging, chemical sensibility, water blocking and scale formation.3. Aim at the solid and liquid damages of reservoir which usually exist during the course of drilling well and completion, the author perfect the receipt of dissolve agent of latent acid, polymer and water, optimize multiple broken down system, on the basis of experiment research. All of which above obtain good effect.4. because the early VES fracturing fluid is of two severeness weakness which is that damages the effective permeability of reservoir and low capability of repeling high temperature, we develop new type water base fracturing fluid system after the effort of working person. Which are free of macromolecule polymer, can gelout completely, do not have negative influence to the diversion capability of fracture.5.After the research, the author has been formed a set of technique of reservoir stimulate and evaluation of low permeability. This set of technique has been used in Jishan low permeability reservoir, which obtain good effect.