Investigation of reservoir characteristics, depositional setting and T–R sequences of the Lockhart Limestone of Meyal Oil Field, Pakistan: a petrophysical approach

Journal of Petroleum Exploration and Production Technology

Nasar Khan¹  Syed Mamoon Siyar¹  Muhammad Awais²  Farhad Ullah²  Aizaz Mukhtiar²  Bilal Wadood²  Mukhtiar Ghani³ 

[1] Department of Geology, University of Malakand;Department of Geology, University of Swabi;Geological Survey of Pakistan;

关键词: Lockhart Limestone;    Petrophysical logs;    Meyal Oil Field;    Reservoir properties;    Transgressive–regressive sequences;    Depositional environment;   

DOI  :  10.1007/s13202-019-0730-x

来源: DOAJ

【 摘 要 】

Abstract The present study is focused on formation evaluation of the Lockhart Limestone in two wells (Meyal-05P and Meyal-10P) located in Northern Deformed Potwar Zone of the Potwar sub-basin, Pakistan. The geological formations ranging from Triassic to Pliocene have been drilled in these wells. The formation evaluation of the Lockhart Limestone mainly involves reservoir potential evaluation, interpretation of depositional environment and transgressive–regressive sequences using petrophysical logs. In either wells, the reservoir characterization is steered by various petrophysical parameters including calculation of volume of shale, porosity, permeability and hydrocarbon saturation. The thickness of the Lockhart Limestone is 50 m and 77 m in the Meyal-05P and Meyal-10P wells, respectively. In Meyal-05P and Meyal-10P wells, the average petrophysical parameters values and ranges are given as follows: volume of shale 48% and 20%; density porosity 1–5.6% and 1–31.7%; neutron porosity 1–23% and 1–42.9%; sonic porosity 1–29% and 1–39%; effective porosity < 1–> 5% and 1–21%; and hydrocarbon saturation 92.21–99.8% and 97–99.6%. The petrophysical parameters indicate that the Lockhart Limestone of Meyal-10P well is quantitatively better reservoir than that of the Meyal-05P. In Lockhart Limestone of either wells, the permeability is < 0.1 mD. The bulk volume water deciphered the presence of vuggy and intercrystalline porosity in the Lockhart Limestone. Similarly, the lithological interpretation using logs shows mainly limestone with minor shales. Different electrofacies are interpreted from the log trends of gamma ray log such as aggrading, prograding and retrograding depositional sequences deposited in tidal channel fill, shallow water, shore line and offshore buildup and regressive-to-transgressive shore face depositional setting.

【 授权许可】

Unknown