The Research On Re-fracturing Technology In Xinli Oilfield

Xinli oilfield belongs to low permeability oilfield, with 14.4% porosity and 6.7md permeability, Two sets of oil-bearing,Fuyu and Yang DaChengZi reservoir,are developed in the depth of 1100-1500 m, The effective thickness of the reservoir is 9.2 m, and saturation 55%.As other low permeable oil fields, fracturing techniques runs through the course of the Xinli oilfield development. No matter new wells put into production or old wells reconstruct, fracturing has been play an important role, and each year the increase occupies 40% or more of the total increases yield. However, with the extended length of oilfield development, the remaining resources quality is becoming worse and worse, leading the re-fracture effect worse year by year, for by fracturing of low permeability oil field, this inevitably will bring great challenge to the development of low permeability oil field.On the basis of recognition of Remaining geological reserves and reappraisal of formation energy, and the information that the oil well output is decreasing year by year. We believe that the Xinli oil field has the material basis and energy basis, fully equipped with the potential of oil.Through the in-depth study of reservoir and the sand, We find out remaining oil enrichment area, Through the in-situ stress and fracturing mechanism analysis, We seize the main contradiction and conflict of the main aspect of the problem, We determined the main technical method about re-fracturing, We break through the conventional design concept, under the premise of the application of conventional process, we increase human intervention, We change the local ground stress under the action of sewage; We stop halfway to the construction and put into temporary plugging agent, in order to improve the net pressure; We integrated application of mature technology, make the construction is synchronous in well group or block, The purpose is to form the interference, complicate the artificial fracture.Through preliminary experiment in 2014 and 2015 the full implementation, The best results have been achieved, We counted 108 wells in 2015 and increased 12421 tons of oil, the average single well increased 115 tons of oil, in the effective period the average single well oil production is expected to reach 150 tons, bringing economic benefits at the same time, we also see the direction of the late Xinli oilfield development.