Overcoming Realtime Formation Evaluation Data Transmission Challenges While Drilling with Microbubble and Hollow Glass Sphere Mud System

Abstract

Abstract The paper describes the challenges faced in Formation evaluation Data transmission while drilling through Mud Pulse Telemetry during first deployment of Hollow Glass Sphere (HGS) and Microbubble Mud Systems in Western Offshore India. The oil and gas operator faces considerable difficulties when drilling and evaluating formations in directional within these low-pressure and depleted reservoirs. HGS and Microbubble Mud Systems was utilized for reducing drilling fluid density for prevention and mitigation of losses, while drilling through a producing reservoir section with low pore pressures. To tackle the issue of significant or complete loss of drilling fluid during drilling in the low-pressure reservoir, a low-density micro-bubble drilling mud system was implemented with a density ranging from 6.3 to 7.5 pounds per gallon (ppg). However, the presence of micro-bubbles in the drilling mud led to easy compression, substantial distortion, and attenuation of the mud pulse telemetry signal. Consequently, the real-time logging-while-drilling (LWD) log suffered from a lack of data density, rendering it less valuable to the client. A detailed Study was done considering the pump efficiency, flowrate, mud pulse telemetry principles, pulser design etc. and a new technique was developed in order to deliver high density formation evaluation LWD Data. Identifying the limiting factors and implementing risk mitigation strategies were crucial steps taken to minimize the loss of real-time data and ensure a continuous and uninterrupted logging-while-drilling (LWD) data stream for operator to make Realtime Decisions. Pulser Servicing, Pulser Design change along with software enhancements helped to deliver Mud pulse Transmission up to 20 BPS. The modified configurations of the mud-pulse telemetry module proved to be of great value in providing an uninterrupted logging-while-drilling (LWD) log with an adequate density of data, meeting the requirements of the operator's sub-surface team. The paper ends with conclusion of best practices which can be incorporated to deliver quality data. This pulser and telemetry system can be clubbed with any LWD Services including NMR, Formation Pressures and Electrical Imaging while Drilling.