Intermediate Casing Cementing Procedure 

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1. PURPOSE 

This procedure provides a complete, API-aligned workflow for safely and effectively cementing an intermediate casing string in an oil or gas well. 

A properly executed cementing job ensures the following: 

• Correct Casing Placement and Centralization: The casing is positioned as designed to maintain a uniform annulus for a consistent cement sheath. 

• Effective Zonal Isolation: The cement creates a durable barrier that prevents fluid migration between formations and the wellbore. 

• Accurate Slurry Placement: Cement is placed precisely across the intended intervals, including the shoe track and any critical zones. 

• Structural Support and Integrity: The cement supports and protects the casing from collapse, pressure loads, and corrosive fluids. 

• Complete Mud Displacement: Drilling mud and other fluids are efficiently removed and replaced with cement to promote good bonding. 

• Reliable Plug and Float Equipment Performance: Plug release and float equipment functions are confirmed and monitored throughout the operation. 

• Clean Circulation and Proper Fluid Conditioning: Circulation ensures clean wellbore surfaces and stable downhole conditions for cementing. 

• Prevention of Sustained Annular Pressure (SAP): The cement achieves adequate strength and volume to avoid trapped pressure. 

 2. PRE-JOB ENGINEERING PREPARATION 

2.1 Verify Casing Program 

Ensure the casing string meets all design requirements: 

• Confirm casing grade, weight, connections, and torque limits. 

• Verify the connection makeup torque envelope (minimum, optimum, maximum). 

• Review the centralizer placement plan to achieve the required stand-off. 

• Check float equipment specifications and availability. 

• Confirm the selected fill policy (autofill or manual fill). 

2.2 Cement Design Validation 

Ensure the cement system is engineered for the expected downhole environment: 

• Validate cement class, density, water ratio, and additive package. 

• Confirm slurry testing meets API RP 10B-2 requirements, including rheology, thickening time, free water, fluid loss, and compressive strength development. 

• Review compatibility tests between cement and drilling fluid. 

Spacer and Pre-Flush 

• Ensure the design, composition, and volumes of pre-flush and spacer fluids are appropriate for mud removal and contamination control. 

Volume Calculations 

• Calculate cement, spacer, and displacement volumes using final TD and caliper logs. 

• Add the required excess volume (typically 10–30%) based on offset data and hole conditions. 

2.3 Operational Checks 

Surface Equipment 

• Confirm pumps, blenders, and cementing units are tested and rated for planned pressures. 

• Verify calibration of densitometers, flowmeters, and pressure recorders. 

Downhole Tools 

• Inspect the cementing head, plugs, and release systems for integrity. 

Safety and Contingency 

• Review NPT contingencies (losses, equipment failure, early set). 

• Confirm all personnel understand JSA and emergency actions. 

Operational Readiness 

• Validate annular volumes, pump schedule, plug release volumes, expected bump pressure, and returns monitoring plan. 

 3. CASING RUNNING OPERATIONS 

3.1 Casing Running and Monitoring 

Connection Makeup 

• Use power tongs and follow the specified torque envelope. 

• Record torque and turns for each connection. 

Casing Fill and Differential Pressure Control 

• Keep the casing filled to prevent collapse. 

• Use autofill equipment when available; otherwise, fill manually at defined intervals. 

• Monitor return flow during filling. 

Operational Monitoring 

• Monitor hook load, drag, and overpull for signs of wellbore issues. 

• Confirm shoe depth and recalculate if necessary. 

• Perform rotation or reciprocation checks when safe to ensure mobility. 

Final Landing 

• Verify the casing shoe depth and secure the casing in the slips. 

• Complete space-out for proper equipment alignment. 

3.2 Centralization and Stand-Off Control 

Centralizer Installation 

• Install centralizers per program to maintain ≥67% stand-off. 

• Confirm that the centralizer type suits the hole conditions. 

Critical Sections 

• Increase centralizer density in the build section, horizontal intervals, and near the shoe track. 

Integrity and Modeling 

• Inspect centralizers for damage before and during running. 

• Ensure planned stand-off matches the engineering model. 

4. WELLBORE CONDITIONING 

4.1 Pre-Cement Circulation and Fluid Quality 

Establish Stable Circulation 

• Start circulation gradually, then increase to the highest safe rate. 

• Confirm stable returns (consistent flow, density, and pressure). 

Optimize Mud Properties 

• Adjust density, viscosity, and gels for effective mud removal. 

• Minimize solids and eliminate entrained gas. 

Cleaning Verification 

• Monitor flowline and shakers for cuttings. 

• Ensure pumped and returned volumes match. 

• Perform a check trip or short trip if required. 

4.2 Circulation Time and Rate 

• Circulate for the planned number of bottom-up cycles to stabilize temperature and condition fluids. 

• Use rates that approach turbulent or efficient plug-flow conditions when feasible. 

4.3 Pressure Monitoring 

• Compare the final circulating pressure with the expected values. 

• Keep ECD within the safe operating window. 

5. CEMENTING EXECUTION AND VERIFICATION 

5.1 Plug Verification 

Bottom and Top Plugs 

• Confirm correct size, material, and condition. 

• Ensure fins and wiping elements are intact. 

• Verify proper storage and handling. 

Bottom Plug Diaphragm 

• Check rupture rating. 

Loading Sequence 

• Confirm that the plugs are loaded into the correct chambers in the cementing head. 

5.2 Cementing Head Function Checks 

• Ensure chamber alignment and seal integrity. 

• Confirm indicator pins and release systems function properly. 

• Verify the head’s pressure rating exceeds MACP. 

6. FLUID AND PLUG SEQUENCE (API-Aligned) 

1. Casing is filled with drilling mud. 

2. Pre-flush, wash, or spacer is pumped to clean surfaces and isolate mud. 

3. The bottom plug is released after the spacer is pumped. 

4. Cement slurry is pumped behind the bottom plug. 

5. The top plug is released after the cement volume is pumped. 

6. Displacement fluid is used to push cement to the final position.