Lithofacie, Minerals and Hydrocarbon Play Elements of the Sedimentary Succession Penetrated by the Drill in Jooak-1 Well, Anambra Basin, Southeastern Nigeria

Abstract

Sedimentological analysis was carried out on ninety (90) ditch cutting samples collected from the Research and Development Division, Nigerian National Petroleum Corporation (NNPC) composited from depth range of 1000ft-6830ft (5830ft) in JOOAK-1 well located in the Anambra Basin. The study was aimed at delineating the sedimentological characteristics of the well with a view to determine the lithofacie, minerals and hydrocarbon play elements of the well. The study was carried out using standard sedimentological sample procedures. The sedimentological analysis was carried out with the aid of the Stero Zoom microscope, which was used to describe the ninety (90) samples in terms of lithology and textural characteristics, which include grain shape, grain colour, grain size and sorting. Subsequently, a lithostratigraphic log was generated showing lithology, grain sizes, lithozones and mineralogical composition. The sedimentary successions penetrated consist of fourteen (14) lithofacie units, these are from oldest to youngest: Sandy Shale Unit 1, 6600ft to 6830ft, Shale Unit 2, 6430ft to 6530ft, Sandy Shale Unit 3, 6030ft to 6380ft, Shaly Sand Unit 4, 5860ft to 6010ft, Shale Unit 5, 5650ft to 5750ft, Shaly Sand Unit 6, 5350ft to 5630ft, Shale Unit 7, 2620ft to 5330ft, Sandy Shale Unit 8, 2480ft to 2550ft, Shale Unit 9, 2260ft to 2340ft, Sandy Shale Unit 10, 2200ft to 2240ft, Shaly Sand Unit 11, 2080ft to 2180ft, Sandy Shale Unit 12, 2040ft, Sandstone Unit 13, 1740ft to 1920ft, Sandy Shale Unit 14, 1000ft to 1660ft. Four (4) minerals were identified in the analysed section of the well and they include; Mica, Iron Oxide (Haematite), Feldspar and Quartz. The hydrocarbon play elements also include four (4) seals/cap rocks, four (4) traps and four (4) reservoirs. The studied JOOAK-1 well situated in Anambra Basin in Southeastern Nigeria has four (4) lithofacies, four (4) minerals and four (4) petroleum play elements.