drilling laboratory the woodlands, … laboratory the woodlands, texas evaluation of tarija...

© 2007 Baker Hughes Incorporated

DRILLING LABORATORYTHE WOODLANDS, TEXAS

EVALUATION OF TARIJA FORMATION SAMPLES


1. Simulator test objectives 2. Inefficiencies relating to drilling the Tarija Formation 3. Hughes Christensen drilling laboratory overview4. Pressure simulator overview5. Tarija sample outcrops in Bolivia 6. Mineralogy test results of the Tarija formation 7. Pressure simulator test results on two samples8. Results evaluation 9. Suggestions

PRESENTATION HIGHLIGHTS


• Cost reduction on rig test vs. lab test• Prove drilling behavior of diamectites with different cutting

structures• Mechanical Specific Energy (MSE) while drilling • Final bottom imprint • Drilling dysfunctions related to rock type • Obtain knowledge to design new cutting structures • REPSOL-YPF co-sponsored the test and provided the samples

PRESSURE SIMULATOR TEST OBJECTIVES


TEST COST – FIELD VS. LAB

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Field vs. Lab Cost Comparison

SimmulatorRig

-192K


DRILLING BEHAVIOR ON THE FIELD

• Low efficiency = Low ROP = High drilling cost • OC and TR as main wear pattern • Limited drilling hours (more bit trips) = High drilling cost • High MSE• Bit and BHA vibrations • Optimization target is unknown and also hard to reach


OFF-CENTER DRILLING

• Rock-Bit interaction • Poor lateral bit stability (BHA and Bit design)• High RPM • Bottom pattern generates track between the rows of inserts • Low efficiency = Low ROP = Short bit runs = Severe wear on bits• Can be associated to natural BHA imbalance • Bit cutting structure also affects behavior


OFF-CENTER ROTATION

• OC simulation of a bit cutting structure • Movement is actually very subtle • Generates bottom tracks of formation between the rows of inserts


OFF-CENTER SYMPTOMS

• Wear pattern concentrates on the cone shell • Can lead to exposing cone bearing (loss of cone)

New Bit

After the runOff-Center


OFF-CENTER SYMPTOMS

• More severe cases under unstable conditions• Shirttail wear on one cone normally reveals OC behavior

New Bit

After the run Off-Center = Loss of the nose


TRACKING

• Tracking simulation of a cutting structure • Bit inserts don’t cover the entire surface • Inserts fall in the same cavity left by a previous insert• Can be coupled to OC mode in certain situations

No Tracking Tracking


• Marks in between the inserts • Inserts with self-sharpening shape• Normally occurs in the outer rows of inserts (more probability)

Marks in between inserts

TRACKING SYMPTOMS


MSE = MECHANICAL SPECIFIC ENERGY

• Can be used to quantify drilling efficiency • Hard to measure on the field (bottom hole parameters normally not available) • Requires measurements very close to the bit• Higher WOB = Higher MSE• Higher RPM = Higher MSE• Higher TQ = Higher MSE• Lower ROP = Higher MSE• Efficiency = 1 = MSE / UCS


DRILLING LABORATORYThe Woodlands, Texas


PRESSURE SIMULATORThe Woodlands, Texas

• Indoor drilling laboratory • Simulates drilling conditions up to

6700m • Can be used to test bits under

virtually any bottom hole condition• Analysis of parameters • Sensors measure bit-rock

interaction• Bottom hole imprint after test • Simulates hydrostatic conditions


PRESSURE SIMULATORThe Woodlands, Texas


TARIJA SAMPLES - BOLIVIA

• Initial mineralogy test samples from Bermejo (Rock A) and Huacaya (Rock B)

• Pressure simulator samples form Aguarague (high clay content) and Isiri(high quartz content)


TARIJA SAMPLES – MINERALOGY TEST

• Smaller samples for mineralogy tests • Rock sample A from Bermejo area • Rock sample B from Huacaya area


MINERALOGY TEST


MINERALOGY TEST RESULTS

• Both rocks are basically the same type according to spider plot• The rock in both cases is medium strength under Mohr-failure

envelope • Higher quartz content reflects higher UCS values • P-S wave behavior shows dissimilar strength behavior • Higher clay content (lower UCS) seems to act as a harder rock

under confinement• Linear relation of UCS may not be a good value to look at when

evaluating diamectites


SIMULATOR TEST SAMPLES

• ISIRI samples show greater compaction and also greater sand content

• AGUARGUE samples show higher clay content, very fractured and low strength. Weathering process show effect on all samples


SAMPLES AFTER CUTTING

• 4 large samples from ISIRI are sent to Savannah, Georgia for cylindrical cutting process

• Only 2 samples survive transport and cutting process (fractured rock)• Surviving samples are protected by fiberglass coating


PRESSURE SIMULATOR TESTS

• Test both samples under equal conditions • SAMPLE A: 12¼” GX-09DX (IADC 437), 7 inner rows, 3 outer

rows, 88 compacts • SAMPLE B: 12¼” EP6312 (IADC 517), 8 inner rows, 3 outer rows,

133 compacts• RPM: 150• WOB: 15-20-25-30-35 Klbs• 450GPM, Water based mud 9.5ppg, Nozzles 3x15, TFA = 0.52in²• 1.47 HSI• 5800 PSI confinement pressure


TEST A: 12¼” GX-09DX

• Bit with no damage • Formation-inserts sloughing on the

bottom• OC initiation (ledges on the wall) • TR on bottom visible • Hard-Sandy formation with ductile

behavior?


TEST B: 12¼” EP6312

Bit with no damage Cleaner bottom imprint

No formation-insert sloughing Very minor tracking evidence

No ledges on the wall


COMPARISON TEST A-B


TEST RESULTS ROP vs Depth

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TEST RESULTS Specific Energy vs Depth

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TEST RESULTS Torque vs Depth

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TEST RESULTS Mu vs Depth

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RESULTS AND COMPARISON

•ISIRI samples show 95% quartz content•Previous samples ROCK A-B show 71% and 58% of quartz content respectively •Color and texture of the rock seem to differ from original samples

•First sample was stuck for 5 days after the test due to fines generation (seals blocked) •UCS values of simulator samples are close to 26KSI which are closer to certain types of granite rock


• EP6312 (new M features) is better adapted to formation properties

• Need to validate results with a field run• Diamectite rock has quite unique properties (hard-

ductile-wave resonance) • UCS is not a good index for diamectites• OC and TR are clearly related to cutting structure

design• DART to implement features on 16-28” bits• More testing of samples is required to get a better idea

on additional rock beahvior

PRELIMINARY CONCLUSIONS

drilling laboratory the woodlands, … laboratory the woodlands, texas evaluation of tarija...

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