Because environmental regulations are rapidly evolving towards stringent requirements, oil and gasoperators are confronted with a great challenge of disposing drilling waste, especially when operating on an artificial island located 120-km offshore and under a Zero Discharge Policy. The paper describes an innovative engineering solution that significantly reduces the time, cost and the associated safety hazards with disposing of the cement waste generated from primary cementing operations and drilled cement cuttings. The earlier disposal process implemented on the island included collecting, storing, and shipping the cement waste to an onshore treatment facility. This process was proven to be cumbersome, time-consuming and extremely expensive. Additionally, external factors such as logistics constraints, weatherconditions, and storage skips availability had a direct negative impact on the process, resulting in a massive accumulation of waste on the island. On the other hand, the newly developed disposal process utilizes existing resources, with minor modification, within the artificial island. A step-by-step procedure was developed to dispose all excess cement and drilled cement cuttings generated without any negative HSE impact. A pilot trial was performed successfully by injecting the cement waste into the shallow loss zone through the annulus, and therefore, the process was generalized to both island and found to be safe and efficient operationally and economically. The new innovative method simplifies the disposal process to a one-stage operation that is performed along with the primary cementing operation. By implementing the process, no cement handling on surface is needed, resulting in a 90-percent drop in the cost.. The number of people involved is reduced as well. Consequently, a reduction in the hazard exposure and the potential lost time incident (LTI) is achieved.

Well integrity is becoming more challenging with drilling of deeper, highly deviated and horizontal wells worldwide while the current market scenario is driving every stakeholder to execute their scope of work under ever revising AFEs. The scope of this paper is to present an optimized approach to improve quality of cement jobs while having a good long term zonal isolation across all the targeted formations and further eliminating the additional costs required for remedial jobs. There are various challenges that need to be dealt with when cementing complex wells such as uneven cement distribution around the casing due to insufficient mud removal, inadequate hole cleaning and poor casing standoff. All these challenges were addressed by in-house developed optimization methodology. The elements of this methodology that positively influenced the quality of the cement bond were (i) Optimizing the rheological hierarchy between the cement, mud and spacer design to create optimum flow during the cement job (ii) Improving hole cleaning efficiency by applying tailor-made spacer technology with aid of modeling software (iii) Optimizing the centralizer profile by including non-survey stations. The in-house developed optimized methodology has yielded excellent results with significant improvement in the cement bond logs when compared to the offset wells. This paper will present the methodology adopted in detail along with the field example of a well in an offshore island that has measured success against the key improved elements. The rheology of the fluids was adjusted to improve the fluid displacement in the analytical software which has played a big role in improving the hole cleaning efficiency. In addition, application of tailored Spacer design has not only showed improved mud removal effectiveness but also helped with reducing the channeling alongside the best optimized centralization found in the field in terms of type, quantity and placement across various formations and direction profiles along the well bore. This paper will also compare different logs in the same field to show the improvement against the new methodology and practices adopted that helped in achieving complete zonal isolation across all formations. The new optimization methodology has resulted in significant improvement in outcome of cement logs across production casing in offshore island indicating an excellent zonal isolation and adherence to well integrity requirements. The key elements that were improved are now being adopted across all the jobs in the field and nearby fields.