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随着油气田开发进入中后期,低渗透甚至特低渗油藏在油气田开发中的地位日趋重要。辽河油田大民屯沙四段致密砂砾岩储层物性较差,平均孔隙度为9.8%、平均渗透率仅0.5m D。储层微观孔隙以粒间孔、溶蚀孔为主,且孔隙结构以细—微细喉道不均匀为主,易受钻井泥浆污染堵塞孔喉,同时存在储层改造破裂压力梯度高、有效率低等问题,严重制约了单井产能。结合区域储层特性,引进了径向钻孔技术。通过建立该地区油藏数值模拟地质模型,研究分析不同钻孔角度以及钻孔长度下对储层渗流场、压裂人工裂缝、油水驱替等的影响。研究发现,在180°钻孔角度和一定钻孔长度下,储层改造可形成多条裂缝,改善地层渗流能力,从而大大提高人工裂缝的控制范围和泄油面积。该技术在本区块共实施3井次,对比常规射孔压裂,单井产能提高幅度较大。
With the development of oil and gas fields entering the middle and later stages, the status of low and even low permeability reservoirs in the development of oil and gas fields is becoming more and more important. The tight sand and conglomerate reservoir in the fourth member of Damintun Formation in Liaohe Oilfield is poor in physical properties, with an average porosity of 9.8% and an average permeability of only 0.5mD. The microscopic pores in the reservoir mainly consist of intergranular pores and dissolved pores, and the pore structure is dominated by fine-fine throat heterogeneity, which is easily plugged by drilling mud pollution to block pore throats. At the same time, reservoir fracturing has a high pressure gradient and low efficiency And other issues, seriously restricted the single well productivity. Combined with regional reservoir characteristics, radial drilling technology was introduced. Through the establishment of the geological model of reservoir numerical simulation in this area, the influence of different drilling angles and drilling length on reservoir seepage field, fracturing fractures, oil-water displacement and so on is studied. The study found that at a drilling angle of 180 ° and a certain drilling length, multiple fractures can be formed in the reservoir reconstruction to improve the seepage capacity of the formation, thus greatly improving the control range and drainage area of the artificial fractures. The technology in the block implemented a total of 3 wells, compared to conventional perforation fracturing, single-well productivity increased significantly.