# Presentation: 287396

## Cement Pulsation “Preventing Annular Flow After Cementing...”

**Minerals Management Service**
**November 30, 2004**
**Ken Newman**
**Ed Smalley**

## Today’s Highlights

**CTES**
**Introduction & Key Products**
**Recent R&D Projects**
**Cement Pulsation to Prevent Annular Flow After Cementing in Offshore Gulf of Mexico**
**Industry Need**
**Technology Overview**
**Instrumented Wellbore Results**
**Field Test Results / Economics**

## CTES Background

**Established in 1994**
**~ 25 employees**** **
**Conroe, Texas**
**Aberdeen, Scotland**
**Products**
**Wellbore intervention modeling software**
**Data acquisition systems**
**Engineering products**
**Consulting services**

## Biography of Ken Newman, P.E.

**MS Mechanical Engineering – M.I.T.**
**1985 - Joined Schlumberger**
**1988 - Dowell CT Engineering Manager located in Rosharon, TX**
**1990 - Dowell Worldwide CT Businessline Manager located in Paris, France**
**1993 - Joined Drexel (now Varco)**
**VP - Tuboscope CT Products Marketing**
**Founder and President of CTES**
**Inventor of the SmarTract well tractor system**
**Has published over 40 CT papers and articles**
**Has over 12 patents**

## Biography of Paul Brown

**MA Engineering - Cambridge University**
** ****12 years at Schlumberger**
**Field engineer**
**Research Scientist**
**Engineering - developing downhole tools**
**Coiled tubing specialist**
**Senior Vice President of CTES, L.P.**
**Leads software development**
** ****Has authored many CT papers and articles**

## Biography of Ed Smalley

**B.S. Engineering – Kansas State**
** ****12 years at Schlumberger Wireline**
**Field engineer, sales engineer, district manager**
- HT/HP Specialist for Anadarko Basin
**11 Years at Gas Research Institute**
**Business Development Director**
-   Commercialization strategy, licensing of new E&P technology
**V.P. Marketing & Business Development at CTES**
**Leads business development activities**

## Biography of Rick Behenna

**BS Petroleum Engineering – Montana Tech**** **
**12 Years at Halliburton Energy Services**
**Halliburton Technology Center-Duncan, OK**
**Operations Engineer – Algeria**
**CT Software Technical Specialist**** **
**Software Manager – CTES, L.P. – May 2002**
**New Product Development**
**Customer Support**

## Major CTES Product Lines

**Software:  *****Cerberus***** Wireline, Coiled Tubing and Jointed Pipe modeling for directional/complex wells**
**Forces**
**Limits**
**Hydraulics**
**Fatigue (CT only)**
**“****PACA” completion design (packer/tubing issues)**
**Data Acquisition Units:  *****Orion, Sirius***
**Applicable to WL, CT, and Pumping services**
**Data gathering, display and storage**
**Real-time modeling and monitoring**
**Engineering Projects and Consulting Services**

## “Argus”Ultrasonic Coiled Tubing Inspection

**R&D Project**

## Argus / CT InSpecUT Method

## ArgusAssembly

## ArgusMounting

## ArgusSakhalin Data

## Milled SamplesRemoved 50% of wall

## Collapsed Sample

## “Zeta”Well Intervention Design & Safety System

**R&D Project**

## Purpose of Zeta (ζ)

**Intervention Design and Safety System:**
**Design Tool**** – Equipment Selection & Supports For a Safe Intervention Stack**
**Dynamic movement of structure & wellhead**
**Monitoring**** – Stress Levels in Wellhead/lubricator Intervention Stack**
**Determine the maximum stresses in a wellhead/lubricator stack**
**Warn when maximum stresses are approaching unsafe limits**

## Where is ζ Needed?Land

## Where is ζ Needed?Offshore

## 2 System Components

**ζ**** - Model**** - Real-time finite-element analysis model**
**Models entire wellhead/lubricator stack**
**Applicable for floating structures and independently moving wellheads**
**Uses real-time input from monitoring device to determine max stress in the stack**
**ζ**** - Gauge**** - in lubricator stack**
**Measures axial strains, hoop strains, internal pressure and temperature of steel**
**Calculates axial load, bending moment and bending direction**

## Enabling TechnologyFiber-Optic Strain Measurement

**High Resolution (****± 1 μ****ε****)**
**Large Range ****(****± 3,000 μ****ε****)**
**No Electricity at the Well**

- Extrinsic Fabry-Perot Cavity Interferometer

- Detector

- Source Light

- Coupler

- Reference Fiber

- Strain
- Gauge

- Glass Tube

- Lead Fiber

- Reflecting Fiber

- Air-Gap

- Attachment Points

## Lab Testing and Calibration

**Side**

**Front**

## First Zeta Field TestMay 12-14, 2004

## ζ – ModelJob DesignReal-TimeMonitoring

_**ζ**__** – Model**_**Job Design****Real-Time****Monitoring**

## Zeta Field Test Results

## BP Holstein

**BP Holstein**
**ζ**** - Model**

## Platform MovementTy = 10 sec, Tz = 5 sec

## Wellhead MovementTy = 9 sec, Tz = 4 sec

## BP Holstein

**5 1/8” Lubricator**
**Lower 25’ Titanium**

## Fiber Optic Cable Injector

**R&D Project**

## Fiber Optic Cable Injection

## “Eliminating Annular Flow After Cementing in Offshore Gulf of Mexico”

**Cement Pulsation**
**R&D Project**

## Industry Need

**Annular flow related to cementing surface casing has been identified as one of the most frequent causes of loss of control incidents in the Gulf of Mexico ****1**
**There are over 11,000 casing strings in over 8,000 wells in the Outer Continental Shelf that have sustained casing pressure ****1**
**15% of the primary cement jobs fail, costing the Oil & Gas industry $470 million annually ****2**
**One-third of these cementing failures are related to formation influx after cementing ****2**** **

**1**** ****Reported by MMS**
**2**** ****Reported by Westport Technology (1995)**

## Problem: Fluid Influx During Cement Gelation

**Loss of Hydrostatic Head Allows Influx of Formation Fluids:**
**Gases**
**Water**
**Results:**
**Fluid migration through the cement**
**Annulus pressure**
**Poor quality cement bond logs**
**Remedial cement jobs & expense**
**Lost production and possibly... ?**

## Avoid This Problem !MMS Safety Alert No. 261/Oct. 2003 “annular flow related to cementing surface casing has been identified as one of the most frequent causes of loss of control incidents in the Gulf of Mexico.”

**Avoid This Problem !****MMS Safety Alert No. 261/Oct. 2003 ****“annular flow related to cementing surface casing has been identified as one of the most frequent causes of loss of control incidents in the Gulf of Mexico.”**

**Notes:**
This is the Adriatic IV rig that burned and sunk in the Mediterranean during the summer of 2004.  
The root cause of this problem was said to be flow after cementing operations, which cement pulsation can help prevent.

## Causes of Fluid Migration

**The Process Begins Once the Cement is in Place**

**Gel strength develops, reducing hydrostatic pressure**

**Fluid leaks from the cement into the formation**

**Cement bulk volume contracts up to 6%, due to the hydration process**

**Cement becomes highly permeable before setting**

## Solution:     Maintain Downhole Hydrostatic Pressure During Gelation

**Previous / Current Technology**
**Vibrate, reciprocate, or rotate casing**
**Apply static overpressure to the annulus**
**Special cement slurries**
**New Technology - ****Cement Pulsation**
**Apply cyclic low pressure pulses to the annulus until cement sets**
**Maintain hydrostatic head until ****	****          compressive strength **_**>**_** pressure pulse magnitude**
**No modification to existing cement job design**
**Simple, low-cost equipment**

## Basic Principle

**Top off annulus with water**

** ****Pressurize annulus with water to P****a**

**Exhaust**
**annulus pressure**

## Concept:  Cement Pulsation

**Apply low-pressure pulses to the annulus after a primary cement job**
**These pulses break the gel strength that forms in the cement**
**Maintain pressure on the formation until the cement develops sufficient strength to prevent the influx**

## Loss of Hydrostatic Pressure During Transition Phase

**Loss of Hydrostatic Pressure ****During Transition Phase**

**Transition Cement**

**Pressure**

**Original Slurry**

**Pore Pressure**

**Transition Slurry**

**Depth**

## Current CP System (Land)

**Current CP System (Land)**

## Data Acquisition & Control System

**Modified OrionTM Data Acquisition & Control System**
**Electronic Memory Unit (EMU)**
**On-board data storage**

## Key Wellsite Data Recorded During CP Job

**Compressible Volume**** **
**Water volume displacement/pulse**
**Real-time indication of slurry setting events**
**Water “Loss” to the Wellbore**
**Inflection points typically associated with cement setting events**
**Water Tank Pressure**
**Annulus pulse pressure**

## INSTRUMENTED WELLBORE RESULTS

***“******Do Small Pressure Pulses Reach T.D. ?”***

## Instrumented Wellbore:Pressure Pulse Transmission

**Objective:  Prove Small Surface Pulses Can be Transmitted to Significant Well Depths**
**Field Experiment Set-up**
**T.D. ~ 8,700’**
**7 7/8” hole, 5 1/2” Csg.**
**Cement column ~ lower 1,700’**
**Three pressure/temperature gauges on outside of csg.**
**Gauges located at top, middle, and bottom of cement column**

**Notes:**
Two wellbores were instrumented with 3 pressure & temperature gauges.
These gauges were cemented in place on a conventional gas well, the well was pulsed, and the downhole pressures were monitored to prove that small pressure pulses applied at surface DO reach the bottom of the well.

## Pulse Parameters: Instrumented Wellbore 

**Apply Surface Pulses of ~107 psi**
**10-second hold/release cycle**
**Test Response After a “Pause” in Pulsing**
**Terminate pulsing 4 times during the test**
**2-3 minute pause w/no pulse**
**Pulse termination resulted in a significant pressure decrease at the gauges**
**Evidence of gel strength**
**When pulsing resumed, hydrostatic pressure recovered**
**Gel strength broken**

## Downhole Press/Temp Gauge (3⁄4” OD)

## Running Downhole Sensors with Casing

## Downhole Measurements whileRunning Casing

## Entire Pulsing PeriodConfirmed Pulses Reach T.D.

**Documented in *****World Oil***** July, 2001**

## First 1 1⁄2 Hour of Pulsing with 4 Pauses

**Hydrostatic pressure decrease of cement column when pulsation is paused.**

**Notes:**
Each of the 3 gauges show a pressure decline (due to cement gel strength development) each time the cement pulsation process is temporarily halted for 2-3 minutes.

## FIELD RESULTS

**Cement Pulsation**
** ****Initial Work in Canada**

## Initial Field Results: Canada

**Comparison of wells using CP versus historical data**
**Fields with known history of gas migration problems**
**28 different fields**
**150 wells in Alberta and Saskatchewan**
**Depth ranged from 1,900’ to 5,900’**

## Historical vs. CP Field Results

**Overall, leaking wells declined from 57% to 21%**
**All fields showed signs of improvement**
**Top 11 fields, accounts for 88% of the wells pulsed**
**All fields with more than one well**

**Initial Field Results - Canada**

## Decline in Leaking Wells

**Initial Field Results - Canada**

**  ****Total Project Cost Savings: $2 Million**

## Conclusions:  Initial Work

**$2 Million Cost Savings Provided by Cement Pulsation on these Initial 150 wells**
**Reduced total well costs by eliminating cement remediation costs**
**Cost savings would enable the Operator to drill an additional 20 wells with the same total project investment**
**Cement Pulsation Has Been Used on Nearly 600 Land Wells in the U.S. and Canada**
**Total Success Rate of 95% for Vertical Wells**
**Success defined as no annular pressure after cementing**
**Vertical wells defined as 30****0**** (or less) wellbore deviation**

**Initial Field Results - Canada**

**Notes:**
Any well with annular flow/pressure after cementing is included in these statistics, even if something else during the cementing job is suspected to have caused a problem (i.e. the casing isn’t centralized properly in a deviated well, mud isn’t properly displaced and cleaned from the wellbore prior to cementing, etc.).

## Summary:Cement Pulsation

**CP Can Mitigate Gas Migration and Annular Flow/Pressure After Cementing**
**Reduce/eliminate cement remediation costs**
**Small (110 psi) Pressure Pluses **_**DO**_** Reach T.D. of an 8,700 ft. Well**
**Real-time Measurements During the CP Process Help Determine When the Cement is Set**

## “Eliminating Annular Flow After Cementing in Offshore Gulf of Mexico”

**Cement Pulsation**
**MMS R&D Project Detail**

## Proposed MMS Project:CP Technology Assessment

**Objective**** **
**Unbiased Assessment of CP Results for Annular Flow Prevention in Offshore GOM**
**Approach**** **
**Adapt CP Hardware & Software for Offshore (R&D)**
**CP Case History Development for 10 Wells (Test)**
**Public Dissemination of CP Results (Tech-Transfer)**
**Incentive/Benefits**
**CTES to Cofund 18% of CP Field Service Cost**
**MMS/Operators to Share Remaining ****	****	****	****CP Service Costs 40/60%  **

## Project Summary by TaskEliminating Annular Flow After Cementing...

**Offshore GoM Applications ($261K) – 12 months**
**Task 1**** ($201K) – 10 Well Case History Development**
**Task 2**** ($37K) – Adapt CP Hardware**
**Skid-mounted air supply & control system**
**Pulse water tank & control**
**CP control & data acquisition system for hazardous areas**
**Task 3**** ($23K) – Modify Predictive CP Software**
**Pulsing of shallow marine sediments **
**Pulse magnitude to avoid formation breakdown while providing adequate treatment of unset cement slurry**

**MMS Project Costs Listed in Parenthesis**

## Task 1 DetailEliminating Annular Flow After Cementing...

**Targeted GoM Blocks & Well Operators**
**Well selection criteria**
**CTES responsible for recruiting Operators**
**Operators Receive Reduced Cement Pulsation  Field Service Cost**
**Agree to release cementing results**
**CTES funds 18%, remainder split 60/40% between Operator and MMS**
**CTES to Create Individual Case History for Each Well, Documenting Results**

## Deliverable SummaryEliminating Annular Flow After Cementing...

**Offshore GoM Applications**
**Task 1**** - Case History Development**
**Documented results from 10 wells**
**Trade journal or technical paper**
**Task 2**** - Adapt CP Hardware**
**Skid-mounted air supply & control system**
**Pulse water tank & control**
**CP control & data acquisition system for hazardous areas**
**Task 3**** – Modify Predictive CP Software**
**Pre-job modeling software for pulsing of shallow marine sediments **
**Compressible volume prediction**
**Adequate pulse magnitude**

## Potential Options:Reducing MMS Yr. 2005 Funding Commitment

**Option 1**** – Obtain Additional Project Funding from DOE (Roy Long, etc.)**
**Option 2**** – Extend Project Term Beyond 12 Months**
**Example:  $130K MMS Funding in Yr. 1**
**$60K - Equipment & software R&D**
**$70K – 7 Case history wells (approx. $9.7K/well from MMS)**

**MMS Funding Required as Proposed = $261K**

## Selected Additional CP References

**SPE Paper #77752 – “Cement Pulsation Treatment in Wells**
**SPE Paper #37616 – “Reciprocating Cement Slurries After Placement by Applying Pressure Pulses in the Annulus”**
**GTI *****GasTIPS***** Fall 2001 Article – “Improving Cement Jobs with Cement Pulsation”**
**CADE/CAODC Drilling Conference Paper #2001-06      ****	**** “Field Study of the Use of Cement Pulsation to Control Gas Migration” (Trican Well Services & Husky Energy)**
**U.S. Patents:**
**5,377,753 - Cement Pulsation Method & Apparatus**
**6,053,245 - Monitoring the Setting of Well Cement**