Kuwait's First Successful Implementation of Managed Pressure Cementing in Deep Jurassic Reservoirs of Kra Al-Maru Field

Abstract

The development of Najmah-Sargelu (NJ-SR) limestone fractured reservoir, has a significant role in Kuwait Oil Company (KOC) 2040 strategy. To achieve this objective, hydrocarbon potential across the NJ-SR reservoir will have to be evaluated in the West Kuwait of Kra Al-Maru (Figure 1). First and foremost, this section will have to be drilled to planned section TD, cased off and successfully cemented. This paper discusses KOC experiences and best practices implemented to ensure utilizing managed pressure drilling equipment to achieve a successful 7-5/8-in liner cement job at well depth of 16,945ft. MD (15,756ft. TVD), and reservoir pressure and temperature ranges of 12,000 - 15,000psi and 230 - 280 deg F respectively.

This new approach to cementing is based on Managed Pressure Drilling technology. It addresses running the 7-5/8- in liner and cementing it in MPD mode. A step-bystep procedure is provided that ensures a constant bottom pressure is maintained throughout the process. Risk assessment showing what can go wrong and mitigations are provided, and the method is described in detail to allow readers comprehend the unique case presented in this paper.

Managed Pressure Cementing (MPC) technique in case study well is compared to offset wells in West Kuwait Field where cementing was conducted conventionally. In most cases, the cement bond logs show cement dispersed throughout the annulus with no continuous bond - channels in the cement behind the casing. The most significant new findings from this paper are that, in a couple of wells where there were no losses while pumping cement conventionally- the cement bond logs showed moderate to poor cement behind casing and channels within the cement.

This technology offers opportunity to achieve good cement bonding with liner in fractured limestone which can be problematic due to the risk of losses and the presence of hydrocarbons with high pore pressure in West Kuwait NJ-SR intervals. This novelty approach using Managed Pressure Cementing technique to case and cement liners in West Kuwait fields and tight margin reservoir will ensure good cement bond logs behind casing and improve well testing and completions strategies.