Fig. 4. Core and microscopic petrological characteristics of the Lower Cretaceous SQ1-SQ3 sequences in M block of the Santos Basin. (a) Well M5, 5 532.00 m, ITP Formation, shell limestone, intergranular siliceous cementation, wellbore coring; (b) Well M5, 5 532.00 m, ITP Formation, shell limestone, micrite envelopes, part of the shells are metasomized by siliceous matter, single polarized light, thin section; (c) Well M5, 5 340.05 m, ITP Formation, shell limestone, with moldic pores and intergranular dissolution pores, core; (d) Well M5, 5 340.05m, ITP Formation, shell limestone, bioclastic recrystallization, with intergranular dissolution pores and moldic pores, blue casts, single polarized light, thin section; (e) Well M12, 5 483.40 m, BVE200 Member, with interbedded shrub skeleton limestone and pelleted limestone at the bottom, biological skeletons grow upwards, developing fruticose skeletons, cores; (f) Well M31, 5 523.60 m, BVE300 Member, fruticose skeleton limestone, with elliptical pellets growing upward to form skeletons, orthogonal light, thin section; (g) Well M12, 5 575.80 m, BVE300 Member, with rhythmic interlayer of pelleted limestone and lamellar argillaceous limestone, core; (h) Well M31, 5450.45 m, BVE100 Member, pelleted limestone, intergranular filling of argillaceous permeable silts, single polarized light, thin section; (i) Well M12, 5 575.80 m, BVE300 Member, pelleted limestone, intergranular filling of dolomite grains and a small amount of insoluble residue, orthogonal light, thin section; (j) Well M12, 5 474.10 m, BVE200 Member, pebbled arenaceous limestone, with reverse grain sequence characteristics longitudinally, core; (k) Well M12, 5 571.75 m, BVE300 Member, arenaceous limestone, with pelleted fragments, orthogonal light, thin section; (l) Well M31, 5 845.00 m, ITP Formation, lamellar shell micrite, wellbore coring.
本文的其它图/表
