Utilizing Managed Pressure Drilling to Overcome Narrow Margins During Liner Running and Cementing Operations

Abstract

In the past several years, managed pressure drilling (MPD) has developed from an emerging technology to become commonplace in many basins and fields. A joint operator / service company team has employed a technique that applies MPD methodology to cementing applications, increasing the probability of achieving successful primary cement jobs. This technique has been termed managed pressure cementing (MPC). This paper illustrates one of the first instances of successful implementation of MPC to run and cement a liner in the Gulf of Mexico (GOM).

In the GOM over the past 4 years, the operator has incurred an average of 6 days of non-productive time (NPT) per primary cementing job failure to perform remedial cement repairs. In the field where MPC was developed, the previous two wells had experienced 25 days of remedial cementing NPT due to failed primary cementing jobs. In each of these cases, losses during cementing prevented achieving adequate top of cement (TOC). The losses were attributed to the narrow margin between wellbore stability (WBS) and fracture gradient (FG).

This paper focuses on cement placement, which is as important as cement formulation to the success of a cement job. Successful cement placement is a function of controlling equivalent circulating densities (ECD) within the design limits of WBS and FG while ensuring that uncontaminated cement fully sweeps the drilling fluid from the borehole to the designed TOC. The MPC job requires significant planning and processes to accurately model running of the liner, the required fluid displacement program, and the execution of the cementing operations. MPC can reduce the overall well cycle time by eliminating NPT due to remedial cementing.