Conventional

Innovative Solutions for Core Handling

Weatherford Laboratories is an industry leader in core retrieval, offering innovative technology for handling, stabilization, and preservation.
Our workflow begins with understanding and meeting our client’s objectives for taking a conventional core. To enhance the accuracy of fluid saturation measurements, Weatherford’s wellsite team can dispense mud tracers into the mud system to quantify fluid invasion levels in the laboratory. Onsite plugging using non-contaminating cutting fluids for obtaining high level Sw and Rw results can be performed inside our onsite buildings.
From the moment the core comes out of the ground, we regard safety as a key component during the handling/lifting phase of the operation.
Maintaining core integrity is essential to a successful coring operation. We provide several techniques for stabilizing the core, including: epoxy and foam stabilization of friable lithologies, Teflon shims for competent intervals, and dry ice freezing an unconsolidated core.
Transporting stabilized core intervals in our advanced GPS, climate-controlled/shock-monitored Weatherford RockVault further ensures that all core material is tracked and cared for as it is transported to the laboratory.

For almost 30 years, Weatherford Laboratories has set the standard for retrieving, preserving, and transporting the core.

Comprehensive Core and Fluid Evaluation

For conventional hydrocarbon reservoirs, Weatherford Laboratories offers more capabilities under one roof than any other technical service option, focusing on customized solutions. These two benefits help you make faster, better informed decisions about new opportunities, or enable you to maximize recovery from depleted reservoirs.

And even though conventional reservoir risks are "lower" than those in cutting-edge plays, you need accurate petrophysical and geochemical interpretations to measure hydrocarbon content, assess reservoir potential, and avoid possible problems.

Reservoir analyses at Weatherford Laboratories are matched to your needs, from wellsite services to laboratory testing. Our adaptive approach applies to all sample types - conventional core, percussion sidewall core, rotary sidewall core and cuttings. No matter what your requirements, Weatherford Laboratories delivers analytical results to match your unique specifications which allows you to make more educated decisions in a timely fashion.

Weatherford Laboratories introduced epifluorescence analysis (including SOP for thin section preparation) for evaluating microporosity and micro-fractures.

Geologic Services

Weatherford Laboratories is an industry leader in geological laboratory analyses, which are critically important in exploration, appraisal, and development.
Weatherford Laboratories performs petrophysical modeling based on images acquired from the industry’s only true Dual-Energy CT Scanner. Standard dual-energy scanning provides high resolution cylindrical unwrapped images, lithology identification, and Rhob and Pef curves used to calibrate downhole logs. Beyond the standard deliverable, Weatherford Labs has developed proprietary mineral models by incorporating the Spectral Core Gamma and x-ray fluorescence (XRF) scanning on the centimeter scale. By applying standard petrophysical calculations to the data acquired on the core, we provide our clients with a complete multi-mineral model (MMM) at a resolution unparalleled by standard logging suites.
All strategic plug sampling is performed using compatible cutting lubricants and directed through appropriate program workflows. Initial sampling typically follows the path through routine core analysis, providing our client’s with accurate porosity, permeability, and fluid saturation data across the cored interval. As different rock types are identified based on the routine properties, additional analyses can be performed to qualify these rock types and better understand their influence on productivity. Our geological staff can assist in guiding these programs, making recommendations for a complete petrographic workup. Weatherford Laboratories has in-depth expertise in conducting thin section petrographic analysis (including digital mosaics) to directly identify grain types and sizes, matrix, cement types, and porosity types. For mineral identification precision, we conduct x-ray diffraction (XRD) measurements on cuttings, sidewall cores, and plug sample endtrims. Weatherford Labs recently adopted a preparation technique called spray drying, which has greatly improved the accuracy for bulk and clay mineralogy determination. Both thin section petrography and XRD are supplemented with scanning electron microscopy (SEM) in order to recognize the location of potentially damaging clays and other mineral components. When integrated with other mineralogical data, SEM allows for evaluation of formation damage and design of remedial treatments. In addition, SEM helps identify log interpretation problems such as low-resistivity pay intervals. 

Weatherford Laboratories has hundreds of years of combined experience in petrophysical evaluation.

Wellbore Stability and Pore Pressure Drawdown Effects on Conventional Reservoirs

Failure to properly measure rock mechanic properties can cause a number of wellbore problems such as borehole instability, casing shear, subsidence, stuck pipe, and sand control issues. Together, these issues are estimated to cost the E&P industry billions of dollars each year in the form of lost or deferred production, expensive remediation, and intervention operations.
Weatherford's rock mechanics laboratory is able to conduct triaxial compressive strength tests on cylindrical core samples to understand how the rock responds to compressional stress. We also perform the unconfined compression test. Combined, this information helps determine the compressive strength, failure envelope, Poisson’s ratio, and Young’s modulus. In determining the Mohr-Coulomb failure envelope, three to four triaxial tests on samples recovered from the same depth are recommended to obtain trustworthy results.
In the conventional reservoirs, we simulate the impact on the formation as the field produces and undergoes pore pressure drawdown. These are commonly referred to as uniaxial strain pore volume compressibility measurements. We measure core samples for bulk compressibility (the relative change in bulk volume due to unit change in applied stress) and pore volume compressibility (representing the relative change in pore volume). To measure the representative in situ compressibility of the core under reservoir production conditions, we conduct drawdown tests under both uniaxial strain and constant axial stress conditions. This test can also be conducted using an overburden ramping method by increasing axial stress while maintaining uniaxial stress condition.
The type of rock strength test to be performed is determined by the type of completion, whether it is openhole, cased hole, horizontal, and/or hydraulically fracturing the formation. Rock mechanics testing provides critical input parameters for the reservoir model.

Weatherford Labs has the experience and analytical tools to understand a core's rock mechanics and how these translate to better well construction decisions in the field.

Use of Special Core Analysis Inputs into Reservoir Simulations

At Weatherford Laboratories, we have the full range of capabilities to provide the necessary inputs for your reservoir simulation. Both capillary pressure and relative permeability play a critical role in tuning the reservoir model. Capillary pressure is a key parameter in determining distribution of fluids in the reservoir. Several methods for measuring capillary pressure are available and carefully selected depending on timing requirements and rock type. These methods range from mercury capillary pressure (MICP) to ultra-centrifuge, and for extended-length testing, the porous plate method is utilized.
Reservoir producibility is controlled by several factors, one of which is relative permeability. With multiphase flow in porous media, relative permeability is a dimensionless measure of effective permeability of that particular fluid phase. Weatherford Laboratories employs a full complement of both steady-state and unsteady-state methods to measure relative permeability.
Dynamic flow techniques such as these are frequently used during our conventional reservoir assessments to assist our clients with ground truth reservoir model inputs and help with field production projections. How these measurements play out depend largely on the wettability of the formation. Wettability plays a key role in understanding basic reservoir properties like relative permeability, capillary pressure, and resistivity. Weatherford Laboratories employs a range of lab methods, including Amott, Modified Amott/USBM, and contact angle measurements to measure the wettability of the rock formation in the presence of different reservoir fluids.

Predicting reservoir performance requires a firm understanding of petrophysical properties: lithology, porosity, permeability, water saturation, and reservoir thickness.

The Geochemistry Toolkit

Oil geochemistry plays a critical role in all modern petroleum exploration programs in conventional reservoirs.
Routine applications of oil geochemistry in conventional reservoirs currently include:
• Assessing charge risk prior to drilling (using oil geochemistry and basin modeling)
• Identifying pay zones in new wells (e.g., using geochemical mud gas logging)
• Characterizing the petroleum systems responsible for an oil show or discovery (using biomarker analyses of shows or produced oils)
• Determining reservoir compartmentalization
• Identifying completion problems in wells
Although oil geochemistry and gas geochemistry can be used to solve a variety of exploration and development problems, such projects require access to oil, rock, and/or gas samples. However, a company which needs these data may not have all the samples "in house" required to conduct a project. Fortunately, Over 9,500 produced oil, seep oil, and piston core samples are available for analysis in various oil collections that can be searched using the online OilTracers Oil Library. This database can lead you to the samples needed to make a project feasible. For the majority of samples, data have already been acquired by the laboratories that own the samples, which are available for purchase.

Chromatography reveals details of the reservoir like no other tool.

PVT and Flow Assurance

The key data obtained from pressure-volume-temperature (PVT) reports include the following: an understanding of fluid composition, density, viscosity, and compressibility; gas in solution; saturation pressure (bubble point and dew point); and flow assurance properties. In conventional environments, Weatherford Laboratories frequently works with conventional oils, volatile oil, gas condensate, and dry gas.
Production and hydrocarbon transport costs are expensive and require a very clear understanding of how oils will behave when mobilized from their virgin, untapped formations. Flow assurance testing is required to ensure economical flow of hydrocarbons will occur from the reservoir to the point of sale. Threats to flow assurance include a diverse set of components in the fluid which, under the right conditions of temperature and pressure, may deposit on the internal walls of the piping and process equipment to slow or ultimately stop flow.
Weatherford Laboratories’ suite of reservoir fluid analysis techniques is designed to identify the various components of the reservoir fluid that threaten flow assurance. We work with our clients to understand the specific flow assurance problems they want to solve. From there, we tailor a customized workflow assurance test protocol to address their challenges. In addition, we are prepared to detect and identify natural gas hydrate potential.

PVT

Weatherford Laboratories PVT analysis guides decisions on the best production scenarios for the long-term viability of the well.

Fines Migration Issues in Unconsolidated and Friable Lithologies/Rock-Fluid Sensitivities

Maintaining consistent production and prevention of formation damage can be a delicate balance.
E&P processes may cause formation damage if they reduce the natural inherent productivity of the formation or reduce injectivity of a water or gas injection well. Formation damage can take place at all stages of a well’s life, from drilling on through to its production decline. Our formation damage studies are custom tailored to identify a problem and offer the appropriate solution that will allow the well to be drilled, completed, and produced in the safest and most efficient manner possible.
Weatherford Laboratories deploys a wide range of formation damage laboratory test methods which are pertinent to conventional completions that go beyond fines migration issues. Regardless of the play type, rock/fluid compatibility warrants a close-up understanding. Simplified benchtop testing such as capillary suction time (CST), or something more sophisticated like regained permeability measurements, can be used. In addition to either of these tests, we recommend that fluid-fluid compatibility be conducted to understand any scale tendencies and determine any rate sensitivities present in the formation. Fines migration problems are recognized during the critical velocity/rate sensitivity tests, which are core flow tests conducted at various flow rates to determine at which velocity certain clay minerals may become dislodged and reduce permeability.
At Weatherford Laboratories, we can help to optimize fluid chemistry and production rates to prevent rock/fluid incompatibility and fines migration issues. Test the rock before risking the reservoir. 

Understanding the fundamentals of the formation rate sensitivities and grain size distributions is crucial in wellbore preparation planning prior to the initial completion phase.