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Below are links of the testing and consulting services offered by STIM-LAB.
Drilling, Cementing and Perforating
Drilling Fluid Evaluations
- Percent Solids
- Rheological Properties
- High Pressure Fluid Loss
- Roller Oven Shale Stability
- Thickening Time vs Additives
- Ultrasonic Compressive Strength
- Unconfined Compressive Strength
- Rheology
- Free Water
- Microscopic Analysis
Perforation Damage Assessment and Cleanup
Selected perforation charges are shot into blocks of rock of the desired lithology.
The flow capacity is measured in special equipment. Acid can be injected to assess
the degree of cleanup vs acid strength and volume. This test is good for optimizing
the perforation type for a particular formation or to optimize cleanup fluids
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Hydraulic Fracturing
Dynamic Leakoff of Fracturing Fluids
Measures Spurt, Cw and equilibrium leakoff rate on actual or samples of similar
permeability vs fluid composition, pressure drop, temperature and shear rate.
Regained Permeability
Regained permeablity with water, oil and methane gas to assess the cleanup of leaked
off fracturing fluids and the impact of surfactants on relative permeability. This
test can be performed in conjunction with dynamic leakoff and is run on cores from
1 to 4 in length or in our multiport long core cell (up to 10 in.)
Leakoff and Regained Permeability of Naturally Fractured Systems
Leakoff and regained permeability are conducted on specially prepared natural fractures
on the reservoir rock. These tests are useful in selecting fluid systems that minimize
damage to the natural fracture production mechanisms that exist in many reservoirs.
Clay Swelling and Migration Tests
Evaluation of salts, salt substitutes and polymer stabilizers in reservoir rock.
The results from these tests can be used to select the optimum type and concentration
vs formation.
Critical Velocity Evaluations
The permeability is monitored vs water, oil or gas rate to assess the rate at which
fines migration becomes a problem.
Conductivity of Proppants
Tests are conducted between 10 sq in core slabs in the patented Stim-Lab system.
Tests show the conductivity vs proppant type, size and concentration at selected
temperatures and closures between slabs of reservoir rock or selected samples such
as Ohio Sandstone. Tests can be conducted up to 400 F and 14,000 psi closure.
Fracturing Treatment Simulations Between Reservoir Rock
Measure the leakoff of fracturing fluids between rock slabs and selected temperatures
and pressure drops. The slurry is loaded to the desired concentration and the conductivity
of the pack is measure vs time at selected rates of water oil or gas. The test indicates
the best fluid additive combinations to control leakoff and and maximize proppant
pack conductivity at the existing reservoir conditions.
Non-Darcy Flow Analysis
The permeability of the proppant pack is measured vs multiphase gas and liquid flow
rates to calculate non-Darcy flow values in terms of beta. The test can be conducted
during a conductivity test or a fracturing treatment simulation. The test is important
in selecting the optimum proppant type, size and concentration based on reservoir
conditions.
SEM Analysis of Embedment and Damage
The embedment of proppant into various formations and the damage of the rock-fluid-proppant
interface is assessed by post test SEM evaluations. Embedment can also be performed
on smaller core samples by performing a penetration depth vs load and ball diameter.
Proppant Flowback Evaluations
The flowback of proppant is analyzed between selected formation rock vs proppant
type, concentration, size and resin-coating. Flowback is evaluated vs gas and liquid
rates at selected closures with and without flowback control aids in patented Stim-Lab
cells. The impact of closure cycling can also be measured. The tests allow the selection
of proppant type and concentration to minimize flowback potential.
Unconfined Compressive Strength of Resin-Coated Proppants
The resin-coated proppant is set in 1 in. diameter by 2 in. long plugs. The Unconfined
Compressive Strength (UCS) is measured to assess strength at a particular set of
conditions. We recommend shear history conditioning the proppant in the fluid to
be pumped. The slurry is place in a Stim-Lab designed cell and is set at the closure
and temperature of the reservoir. The compressive strength is then measured before
and after cycling a desired number of times to the final reservoir closure. These
tests can be run in conjunction with the flowback evaluations to determine the minimum
UCS required to prevent flowback with cycling.
Rheology of Fracturing Fluids
The rheology of fracturing fluids is measured in conventional rotational viscometers
(Fann 50) with or without shear history conditioning vs time at temperature and
vs fluid composition. Tests are also performed on a large scale with full size pumps
and coiled tubing for shear history simulation and the rheology is measured in a
pipe rheometer.
Proppant Transport
The slurry is mixed in a full scale blender and pumping system and is pumped through
heated coiled tubing to simulate shear history and heatup. The proppant transport
is observed in a series of see-through slots. The proppant is video-taped as it
travels through the slots vs time. Tests are conducted to observe proppant transport
vs gel and crosslinker vs temperature and breaker content. These tests should be
run with recommended breaker amounts for cleanup to see if the fluid retains proppant
transport character.
Break Tests
Conventional break tests in pressurized bottles in an oil bath can be run to look
at the break characteristics vs breaker concentration at a desired reservoir temperature.
Dynamic tests can be run in specially designed bottled in a roller oven. The rheology
is measured periodically on conventional and/or low shear rheometers. Test is useful
for assessing the impact of various waters and additives such as resin-coated materials
on break characteristics.
Rock Mechanical Properties
The Young's Modulus and Possion's Ratio are determined in specially designed rock
mechanics equipment on 1 to 1.5 in diameter core plugs that are 2 to 3 in long.
The laboratory measurements are used to calibrate dipole sonic logs.
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Completion Engineering
Fracture Design
Hydraulic Fracture Design work is carried out on a contract basis by our experienced
staff using the fully 3D model GOHFER,
which is a joint development of Marathon Oil Company and Stim-Lab. The program uniquely
uses leakoff, fluid rheology and mechanical properties data to accurately describe
the generated fracture and proppant placement. The designs can be carried out in
advance of the treatment and/or on location with prefrac analysis.
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Fracture Design Classes
In-Lab Training Courses
- Core Flow & Acidizing
- Rheology
- Proppant Testing
- Quality Control
Consortia
The influence of Fracturing Fluids upon the Conductivity of Proppants Rheology and
Proppant Transport of Common Fracturing Fluids Acidizing: Matrix sandstone, carbonate,
fracture acidizing and diversion.
Screen Cleanup
Casing Cleanup
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Other Large Scale Testing
Friction Reduction Testing
The friction reduction of water, oil, gelled water or oil and foams is measured
in pipe rheometers vs pipe size and rates scaled to field Reynold's numbers.
Large Scale Tool Evaluations
The impact of proppant type and concentration and rate vs time on crossover tools
and packers and perforations is assessed in a large-scale test using field blenders
and pumps.
Screen Evaluations
Wellbore screens used in vertical and horizontal wellbores are tested in a 6 ft
or up to a 40 ft model to look at sand retention, drill-in fluid plugging, wellbore
collapse and cleanup. Smaller scale tests are run on screen samples in a 1 to 2
in diameter core holder. Collapse and burst pressure tests can be performed on 6
ft screens.
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Acidizing
Sandstone Matrix Acidizing
Matrix acidizing tests are conducted in a long core multiport cell to determine
permeability of the core vs length and time vs acid type and concentration with
and without mud damage. This is useful to match the acid strength to the formation
and damage that might exist.
Acid Leakoff Rate
Acid and additives is flowed past a long core at selected pressure differentials
to measure the acid leakoff rate or wormholing rate. Core holders are available
for performing tests up to 3 ft long. Penetration is assessed with x-ray. A wellbore
model is available for running up to 3 cores simultaneously to assess acid penetration
rates vs pumping rate, acid strength, viscosity and temperature with or without
mud damage.
Acid Diversion
Diversion is evaluated in a series of long cores (usually 2 or 3 1 in by 6 in long
cores). Also the diversion test can be carried out in a radial core holder with
2 or 3, 4 to 6 in diameter cores with a 0.375 in. wellbore. The test can be run
with foam.
Static Acid Corrosion Tests
Coupon corrosion tests are run in autoclaves at the desired acid concentration and
temperature vs time.
Dynamic Acid Corrosion Tests
Acid or gelled acid is flowed through a loop past coupons mounted na specially designed
cell at temperatures up to 350 F. The weight is measured vs time to calculate the
dynamic corrosion rate.
Acidizing Flowback Samples
Matrix acidizing flowback samples are analyzed for Si, Al, F, Ca, Na, Fe and other
elements as required. Plots of elements vs time can be created with rate and time
information.
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Quality Control
Fracturing Fluid Flowback Sample Analysis
The water and gel flowing back from a well is analyzed for salts, gel content, breaker,
pH and other desired additives. The results are plotted vs time and flow rate to
arrive at the percent gelling agent returned to the surface.
Analysis of Proppant Flowback Samples
Proppant and/or formation samples returning to the surface are analyzed for distribution,
mineralogy by x-ray, and percent resin by Loss on Ignition (LOI).
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