Petrophysical Analysis Of Mari Deep-06 And Mari Deep-09 Wells, Central Indus Basin, Pakistan

Abstract

The Mari Deep-06 and Mari Deep-09 well was drilled to evaluate an exploration prospect in the Mari Gas Field, Pakistan. The Petrophysical Analysis of these two wells was performed to get the knowledge about the reservoir characteristics in relation with the hydrocarbon properties and determining potential zones of hydrocarbons. A significant gas reservoir discovery has been made within the Habib Rahi Limestone as well as in the Lower Goru Sands. To evaluate the Formation, a conventional suite of wireline logs including gamma ray, caliper, sonic, density, neutron and resistivity logs were acquired. The Habib Rahi Formation of Mari Deep-06 has a major zone ranging from 686.4m to 760.4m and has a thickness of 74m. The average calculated parameters in this zone are volume of shale that’s 21%, effective porosity of 18% and saturation of hydrocarbon is about 75% while the Habib Rahi Formation of Mari Deep-09 also has a major zone starting from 707m to 764 and has a thickness of 57m. The average calculated parameters in this zone are volume of shale that’s 26.6%, effective porosity of 16.5% and saturation of hydrocarbon is about 65.6%. The analysis of Habib Rahi Formation indicates that the zone in both well exhibits the less volume of shale, highest hydrocarbon saturation and high effective porosity holds which is favorable for hydrocarbon exploration and it holds greater potential for hydrocarbon reserves. The Lower Goru Formation of Mari Deep-06 has evaluated three hydrocarbon bearing zone named as Zone 1 (2665-2669.5m), Zone 2 (2700-2713.875m) and Zone 3 (2718.75-2740.25m) along with their thickness of 4.5m, 13.875m and 22m. The average calculated parameters in these three zones are volume of shale that’s 7.39%, 9.4 and 4.6%, effective porosity of 8.22%, 8.5% and 9.7%, and saturation of hydrocarbons is about 64.7%, 80.3% and 73%. Due to the unavailability of Lower Goru data in Mari Deep-09 we cannot calculate its physical properties. The analysis indicates that Zone 2 exhibits the highest hydrocarbon saturation and nearly less effective porosity as compared to zone 3, suggesting it holds greater potential for hydrocarbon reserves within the Lower Goru Formation. The trends of the neutron-density cross plot of Habib Rahi Formation of both wells indicates that there is a small contribution of dolomite in the reservoir while in case of Lower Goru Formation of only Mari Deep 06 the neutron density cross plot shows major part is sandstone with some part of dolomite. The low density and low neutron porosity cluster also indicate the presence of gas in both Formation of both wells.