The Rockvault advanced core transportation system maximizes retention of in situ fluids and minimizes structural damage from microfracturing.

Innovative Solutions for Optimizing Core Handling for Unconventionals

Our unconventional 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 employs wax preservation as the preferred preservation technique, along with our RockVault™ core transportation system. The RockVault™ is a fully contained portable refrigerator capable of GPS tracking and shock and temperature monitoring. In addition, core stabilization by shimming the core in the inner liner locks the core in place to prevent mechanical damage from occurring during core transport.
The clock begins to tick the moment the core comes out of the ground. Alteration of the core by mechanical damage and desiccation results in inaccurate data, which is used to make critical decisions for wellbore placement and fracture staging. Entrust your wellsite core handling and stabilization to the team that has a vested interest in the preservation of your core. Entrust your operation to the Weatherford Laboratories wellsite team. 

Sweetspot Identification in Unconventional Reservoirs

Although there are many pathways to reach unconventional reservoir assessment and sweetspot identification, there are three basic data requirements:
1. Hydrocarbon saturation and basic properties of the reservoir
2. Thermal maturity and organic content
3. Depositional environment and mineralogy
Weatherford Laboratories Dual-Energy CT Scanning technologies are unmatched in the industry. Standard dual-energy scanning provides high resolution cylindrical unwrapped images, lithology identification, and Rhob and Pef curves used to calibrate the 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. With the extreme level of heterogeneity seen in unconventional reservoirs, resolution can mean the difference between success and failure. Combining a calculated brittleness index, bulk mineralogy by volume, and calculated kerogen tracks provides greater insight into the reservoir on a scale that is meaningful enough to make informed decisions faster. An added benefit of working with a full-service laboratory is the calibration of the mineral models by using real lab results. Results like total organic carbon (TOC) and x-ray diffraction (XRD) mineralogy allow for confirmation and calibration of the model’s output. 

Success of an unconventional well depends on identification of the target interval or "sweetspot".
Fluid saturation analyses are of critical importance in a proper shale evaluation program.

Understanding basic rock properties is critical in any lithology. Knowing how to measure these properties in unconventional rocks comes with experience.

Shale rock properties provide fluid saturation information, along with porosity and pressure-decay permeability measurements. From proper wellsite handling and preservation to a process-based laboratory procedure developed specifically for unconventional reservoirs, Weatherford Laboratories provides the most accurate data in unconventionals. Fluid saturations, porosity, and permeability numbers are only the beginning in a shale analytical program.

Geochemistry is used to evaluate the source richness, thermal maturity, and organic matter type of the source rock.  Knowledge of these basic geochemical properties allows for better predictive modeling of hydrocarbon type and volumetric calculations of in-place hydrocarbons.  Using extraction techniques to perform bulk fractional and quantitative gas chromatography on the extracted hydrocarbons provides valuable insights into the quality and producibility of the oil.  Isotope analysis of gases from the wells can type the gas to the source and provide thermal maturity and compartmentalization indicators.  Further, gas isotopes have been used as a tool to mitigate environmental litigation.

Geochemical studies can be performed on many sample types, including: cuttings, RSWC, PSWC, core, and produced oil and gas.

 Mineralogy is of great importance in unconventionals, mainly centering on clay types present in the formation.  Swelling clays are accurately quantified using X-Ray Diffraction and visualized using Thin Section and SEM techniques.  Knowing the type, volume, and location of potentially fluid sensitive minerals allows the operator to optimize the chemistry of the drilling and completion fluids in order to alleviate formation damage.  

Mineralogy is a control on brittleness and assists in the identification of high fracability target zones.
There are a myriad of formation damage challenges that threaten the fracture network and overall production of the well.

Fluid chemistry optimized for the rock type reduces formation damage, leading to higher productivity and lower NPT due to wellbore stability issues.

Formation damage testing in unconventionals centers around three basic tests: capillary suction time (CST), roller oven disaggregation test (ROT), and the linear swell meter test (LST). Each test provides a view of how the rock/fluid interaction will impact the swelling and fluid sensitive minerals in the formation. Optimizing the chemistry of the fluids has saved operators millions in fluid costs and destructive formation damage to the wellbore.

Mechanical Properties

The mechanical properties of the target interval must be fully understood in order to identify the horizontal wellbore placement zone and design an effective hydraulic fracturing program. Fracture stage optimization and fracture modeling by incorporating measured Young’s modulus and Poisson’s ratio data from core analysis reduce risk and create higher producing wells. Wellbore stability issues can be predicted and avoided through Weatherford Laboratories’ RM Pro approach to Mohr-Coulomb failure analysis. Proppant embedment testing evaluates various proppant types and sizes for effectiveness. Selecting the best-performing proppant optimizes the amount of proppant that can be put away in the fracture network and ensures the hydraulic fracture will remain open during production.

Failure to properly measure rock mechanics properties can cause wellbore problems such as borehole instability, casing shear, subsidence, stuck pipe, and sand control issues.

Data integration pulls the entire project together.

Integrating data from even the most basic of unconventional shale programs can be a huge undertaking, requiring highly trained and experienced geologists, petrophysicists, and completion and reservoir engineers. The Weatherford Laboratories Integrated Laboratory Services (ILS) group has the insight, knowledge, and combined geological and petrophysical experience to fully integrate and interpret all lab and log data from your well. Get the most out of your data by leveraging our experts who have over 4,000 years of combined global experience.

The Weatherford Laboratories ILS group provides the final piece of the puzzle by interpreting both log and core data.