Fracture and Fault Characterization

Reveal finer geological details with expert interpretation of fracture modeling and detailed imaging

Fractures and faults can often be identified with borehole images from both wireline tools and LWD measurements. Fractures can be identified as a planar feature crossing the wellbore with no displacement on either side of the feature. A fault is identified by a feature that has displacement on one side of the feature versus the other and bed truncation into the feature plane.

Natural fractures and fault identification

Natural fractures are the imprint of tectonic and structural history of the rock section. These fractures are distinguishable in high-resolution borehole images because they are continuous across the borehole image and typically bold with good clarity and sharp edges to the feature. The accuracy of the borehole images paired with skilled image interpretation helps to understand if fractures are open, partially open, or healed, which leads to optimized fracture characterization for enhanced well testing and production.

Quantitative description of the nature, density, and trends of the fracture network around the well becomes essential when supporting completion solutions, solving production uncertainties related to naturally fractured reservoirs, confirming the real-time direction, and optimizing the plan of future well trajectories. The Petrel E&P software platform eases the user tasks while converting interpreted fractures into a detailed discrete fracture network model and refining the structural model for more accurate reservoir simulation.

A horizontal borehole image acquired while drilling with the MicroScope service is shown here with correlated dip data, which is identified by sinusoids and tadpoles for bedding planes (green), conductive fractures (dark blue), resistive fractures (light blue), and faults (magenta). To their right are a well projection, fracture and fault strike rosettes, and a bed boundary azimuth rosette with vector plot analysis.

A structural cross section was generated with fracture and fault rosettes by geologic interval.

Drilling-induced fractures and borehole-breakout identification

Drilling-induced fractures are easily recognizable in most situations with borehole imaging tools. The fracture azimuth reveals the maximum stress orientation, which is critical information for well planning in horizontal completions. Borehole breakout can also be seen with imaging tools. The azimuth of the borehole breakout is at 90° to the drilling-induced fractures and serves as confirmation of the present-day, in situ horizontal stress field orientation. The azimuth is also used to guide the trajectory of the horizontal well section in the plane of least horizontal stress.