ormation evaluation at the wellsite was initially carried out by geologists examining cuttings and formation gas collected from the mud stream and “lagged” to bit depth, a practice known as mud logging or surface logging. Over the years, technological advances and economic viability allowed ever more complex downhole measurement tools to be created and run. These MWD and LWD tools determine several formation properties and have become uniquely associated with formation evaluation.
In today’s business climate, upstream oil and gas companies are increasingly focused on capital efficiency and return on investment (ROI). Delivery of an acceptable ROI to private and public investors is currently challenging in unconventional plays. However, these challenges also apply offshore with its high cost operations, the focus on trimming budgets, reduction of nonproductive time (NPT) and risk, and getting the best data at the best price.
By reinventing mud logging through the development of robotic solutions and advanced software for the collection and analysis of drilled cuttings, including real-time geochemistry at the well site, Diversified Well Logging (DWL) is providing a tool to help operators achieve better capital efficiency and ROI. As a result, high-resolution quantitative data at low risk and cost are available for geologists and engineers, meaning that formation evaluation can return to the surface.
Using drill cuttings and benchtop portable X-Ray fluorescence (XRF) instruments, rigorous laboratory quality control procedures can be applied to provide near-real-time elemental rock measurements. Combined with drilling data, formation gas and artificial intelligence (AI) methods, including machine and deep learning, an important window into the subsurface is now available.
ormation evaluation at the wellsite was initially carried out by geologists examining cuttings and formation gas collected from the mud stream and “lagged” to bit depth, a practice known as mud logging or surface logging. Over the years, technological advances and economic viability allowed ever more complex downhole measurement tools to be created and run. These MWD and LWD tools determine several formation properties and have become uniquely associated with formation evaluation.
In today’s business climate, upstream oil and gas companies are increasingly focused on capital efficiency and return on investment (ROI). Delivery of an acceptable ROI to private and public investors is currently challenging in unconventional plays. However, these challenges also apply offshore with its high cost operations, the focus on trimming budgets, reduction of nonproductive time (NPT) and risk, and getting the best data at the best price.
By reinventing mud logging through the development of robotic solutions and advanced software for the collection and analysis of drilled cuttings, including real-time geochemistry at the well site, Diversified Well Logging (DWL) is providing a tool to help operators achieve better capital efficiency and ROI. As a result, high-resolution quantitative data at low risk and cost are available for geologists and engineers, meaning that formation evaluation can return to the surface.
Using drill cuttings and benchtop portable X-Ray fluorescence (XRF) instruments, rigorous laboratory quality control procedures can be applied to provide near-real-time elemental rock measurements. Combined with drilling data, formation gas and artificial intelligence (AI) methods, including machine and deep learning, an important window into the subsurface is now available.
- Accurate stratigraphic wellbore positioning;
- Improved understanding of depositional environment and provenance;
- Improved understanding of reservoir quality;
- Facies characterization;
- Modeled mineralogy;
- Estimation of clay composition;
- Relative grain size indication;
- Cavings ID related to wellbore stability;
- Drilling hazard mitigation (chert beds);
- Integration with gas data for fluids ID, compartmentalization and connectivity;
- Quantitative formation evaluation and correlation;
- Geosteering (or elemental/chemosteering);
- Improving drilling efficiency;
- Avoiding geohazards and reducing NPT; and
- Optimizing landing targets or casing points.
Vast amounts of information can be garnered from rocks and gas collected at the surface while drilling. XRF elemental data are used to model mineralogy, total organic carbon, matrix density and estimate parameters such as bulk density and porosity. This is all achieved without the cost and risk inherent in running downhole tools. Downhole tool acquisition costs from wireline and LWD are estimated to be in the range of $14 billion annually, according to Spears and Associates. While downhole tools can fail with loss of data, become stuck or lost in hole, elemental data from cuttings are always available for formation evaluation. With advanced software, synthetic logs can be created for advanced geological, geomechanical and petrophysical use.
Drilled cuttings and mud gas provide a physical sample of the subsurface. With quantitative elemental analysis and EGR, users can be confident that the samples are on depth and representative. These two factors are one reason why the industry has historically been reluctant to utilize the full potential of drilled cuttings. With the focus on cost and reduction in risk, HML is a major step change in providing quantitative data in near-real time without increasing personnel. With automation and robotics integrated with the power of AI and deep learning, the Robologger will be the next step transformation in mud logging by providing high-resolution, quantitative sample collection and analysis in real time with a reduction in personnel. This surface MWD provides high-resolution, quantitative data in real time at reduced risk and greater value and helps the industry achieve better capital efficiency and ROI.