深潜山碳酸盐岩双品质压裂层优选技术及应用

廊固坳陷河西务潜山带深潜山碳酸盐岩储层,基质孔隙低、非均质性强,自然产能低,只有进行大型酸化压裂才能获得高产。如果只进行井筒储层划分,不考虑井旁储层及工程参数评价,会出现压前储层评价与压后效果差异较大等复杂问题。利用常规及成像测井资料可以对裂缝、溶洞、物性等储层品质特征进行精细刻画及定量评价;远探测阵列声波资料,可以对井旁远端的地质体构造成像,得到最小水平主应力、脆性、破裂压力等岩石物理工程品质参数。通过储层品质与工程品质综合评价指数模型及评价标准的建立,形成井壁储层精细评价与井旁工程参数相结合的立体评价方法,实现碳酸盐岩储层段的双品质有效评价,为压裂施工设计、优选压裂层段和措施改造提供了可靠的依据。通过河西务潜山带的应用,多口井获得突破,提高了选层的精准性以及地质认识的指导性,为深潜山非均质储层酸压改造及高效勘探开发提供了技术支撑。

Optimizing fracturing layers based on reservoir and engineering quality for deep carbonate rocks:Application to deep buried-hill zone,Bohai Bay Basin

In Hexiwu buried-hill zone,Langgu sag,Bohai Bay Basin,most deep buried-hill carbonate reservoirs are featured by low matrix porosity and strong heterogeneity,bringing about small natural productivity.So,high yield can only be obtained by largescale acid fracturing.If only wellbore reservoirs are divided without taking an evaluation on near borehole reservoirs and engineering parameters into consideration,there are some induced complexity,such as great difference between prefrac reservoir evaluation and postfrac effect.Conventional and imaging well-logging data can be used for the fine characterization and quantitative evaluation on such reservoir quality as fracture,karst cave,and physical property.The remote acoustic array data can be used to image the geological structure at the far end of wells,and some parameters of petrophysical engineering quality containing the minimum horizontal principal stress,brittleness,fracturing pressure can be gained.So,via establishing a comprehensive evaluation index model and an evaluation standard of both reservoir and engineering quality,a three-dimensional evaluation method was developed,which combines fine wellbore reservoir evaluation and near well engineering parameters together.Thus,the double-quality effective evaluation may optimize carbonate reservoirs,and provide reliable basis for fracturing design,fracturing-layer optimization,and measure improvement.Since its application to Hexiwu buried-hill zone,breakthrough has been made in several wells,and the accuracy of optimizing layer and the guidance of geological understanding are improved,which may provide technical support for deep buried-hill heterogeneous reservoirs to implement acid fracturing and efficient exploration and development.