Unlock Hydrocarbon Potential of Najmah Kerogen Unconventional Reservoir (West Kuwait)

Abstract

Hydrocarbon exploration and production in unconventional reservoir is under-developed in Middle East. Therefore, the understanding about this subject is still scanty which leads to conspicuous uncertainties in comprehensive reservoir evaluation and development. It plays a critical role to minimize the cost of exploration, drilling and operations. Detail plan for core acquisition and study is crucial to provide accurate and sufficient information to unlock the potential of Jurassic unconventional reservoirs in West Kuwait (WK). Hydraulic fracturing has proven to be a successful technique for increasing the productivity of unconventional reservoirs. However, before reaching that step, many factors should be intensively evaluated to minimize the risks. A potential area to place a MSF well should satisfy several criteria: high TOC, hydrocarbon maturity (oil, wet gas, or gas), less bitumen, proper containment to hold the vertical extension of fractures beyond the upper/lower boundary, etc…This paper aims to describe the integrated process of reservoir characterization to identify Najmah Kerogen sweet spots in order to facilitate the first Multistage Hydraulic Fracturing (MSF) well in West Kuwait (WK) unconventional reservoir. The study showed that Najmah Kerogen reservoir in WK fields has world-class quality of hydrocarbon potential: average TOC is 10-13%, Kerogen type II/III, mostly in the oil window except some fields have high potential of wet gas/condensate. Thermal maturity increases basin-wards from South-East to North-West. The reservoir is organic-rich mudstone that comprises mainly calcite, dolomite, quartz, kaolinite, and pyrite. In general, the middle unit has lower organic content and higher brittleness compared to the upper and lower one. The reservoir characteristic of the middle unit is favorable for landing the MSF well. The upper unit contains high bitumen amount, so it should be voided in the plan of MSF. Fracture analysis shows the majority of natural fractures are following NNE-SSW direction that in line with regional tectonic understanding and results the favorable drilling direction in NW-SE to ensure the wellbore stability and maximize the efficiency of hydraulic fracturing job. As a result, Field-H was identified as the best candidate to drill the first MSF well in Najmah Kerogen (middle and lower unit) from the outcome of the study. The comprehensive understanding of Najmah Kerogen was crucial to develop unconventional reservoirs in WK fields, especially when the development of unconventional reservoirs is still in the early phase.