The West Delta Deep Marine (WDDM) fields are a Pliocene gas fields located in offshore Nile Delta, approximately 120km North-East of Alexandria, Egypt. These fields are comprised of sandstone reservoirs which are dominated by unconsolidated sandstone. Sand production has become one of the main issues in WDDM since the discovery of a hole in the body of a liquid outlet valve from the onshore slug catcher. On further inspection, it was discovered that the hole had developed due to the presence of sand/fines causing erosion at the interface in the liquid handling system. Scarab-Saffron field was the primary source of sand production in WDDM with screen failure as the cause of the problem. This paper details a method for determining maximum safe production rates for sand control wells. This method was developed from a thorough compilation of data from around 51 sand control wells. As a result of this analysis, a simple function of screen erosion limit has proved to be very reliable at identifying wells operating safely from those resulting in damaged screens or unacceptable amounts of produced sand.

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Setting cement plugs for sidetrack operations is a critical, challenging, and time-consuming operation. In many cases, a successful sidetrack operation requires several cement plug attempts or lengthy drilling operations, resulting in increased operation cost. In the past, when required to sidetrack a well, cement kickoff plugs were regularly tagged without having achieved the desired compressive strength, with added risk of stuck pipe in soft cement and increased wait-on-cement (WOC) time. The poor cement plugs usually resulted in a time drilling operation after additional WOC time. Placing a successful kickoff-plug (KOP) consistently on the first attempt is required for a cost-effective sidetrack operation, which, by itself, is considered an additional cost to any drilling project. In the Awali field in Bahrain, drilling operations faced the challenge of increased loss time in KOP operations. Operator wanted to reduce WOC time by improving the performance of the cement KOPs. The target was to complete the sidetrack operation in well depths less than 3,000 ft and static temperatures of about 140°F within 8 to 12 hr, after the cement plug has been placed.A thorough analysis of previous design and execution cement practices was performed to identify the actions needed to optimize the previous performance of cement plugs. Advanced cement plug optimization software was used to support the evaluation of the risks associated with the placement of the slurry. Data from extensive laboratory testing of several cement slurry systems were used to evaluate the effect of the slurry properties on optimizing the system deemed most suitable for this application. The studies also included a detailed review of the industry best practices that are applicable to the conditions of the field. The results of the implemented best practices for the design and execution of KOPs in shallow wells in the field under study demonstrated an improvement of the success rate to 100% and better cement plug performance, contributing significantly to minimizing the time and cost of performing sidetrack operations.

Depletion of conventional hydrocarbons reservoirs have led oil and gas operators to extend the boundaries and pursue production from reservoirs with high viscosity hydrocarbons that in the past were impossible to be produced and allow the hydrocarbons in place to flow to the surface with conventional production methods. With the introduction of enhance oil recovery techniques (EOR) operators has been able to economically produce from these reservoirs. The steam flood is an EOR technique that allows heavy oil hydrocarbons to be produced and increase the recovery of original oil in place (OOIP). This technique requires high temperature steam to be injected into the reservoir in order to allow hydrocarbons production, introducing challenges in order to maintain well integrity and long term life of the well. Suitable surface facilities, equipment and materials that withstand these challenging conditions are required in order to guarantee the success of the project. In a heavy oil shallow reservoir in Bahrain, a steam flood pilot project has been executed, injecting steam up to 650ºF into the injectors wells in order to enhance the hydrocarbons production in the adjacent production wells. Conventional cement systems will fail when exposed to the given conditions as the mechanical properties of such cements are not sufficient to withstand the stresses created in this extreme temperature environment. This will consequently threaten the well integrity and success of the project. In order to provide a reliable and durable zonal isolation, an engineered cement system has been introduced. This cement system possesses sufficient flexibility (low Young's modulus), and a high coefficient of thermal expansion to withstand the metal casing expansion during the heating step of the process, without failure. This cement system exhibits stable mechanical properties for a long duration during the whole process of the heavy oil production and can be mixed and pumped with conventional cementing equipment. It is placed at low (110-140°F) temperature, acquires sufficient compressive and tensile strength to withstand the heating cycles. Over 50 wells have been cemented using this technology in Bahrain. Cement bond longs and temperature logs demonstrate well integrity has been achieved, allowing the steam to be injected into the target reservoir. Furthermore, no issues have been seen related to steam break through to surface. The project has been implemented for over 4 years with no sign of wellbore integrity failure. This study covers several aspects of the design, execution and evaluation of the cement system.