Field Mapping of Formation Complexity to Solve Drilling Challenges

Abstract Drilling through 8.375-in and 5.875-in curve and lateral sections in gas fields involves hard and abrasive formations with varied thickness and characteristics. These sections require multiple bit trips, influenced by factors like formation abrasion index, hardness, interbedded layers, and varying sandstone and siltstone percentages. The project's objective was to conduct field mapping to understand these variations and develop a solution to reduce the number of trips needed to complete the sections. The proposed solution involved analyzing the formation characteristics of each well in the field. A comprehensive study was conducted, integrating thorough analysis of offset well data, including well logs (sonic, gamma-ray, density-neutron, etc.), formation tops, mud logs, rock mechanics, drilling parameters, drill bit records, and dull bit conditions. Wells were plotted on a contour map to identify areas with high abrasion index, high interbedded index, and formation hardness. This detailed analysis aimed to enhance understanding of the geological variations across the field and improve decision-making for drilling operations. The target wells can now be visualized on the field map, which helps identify the formation complexity in nearby offset wells. By analyzing factors such as unconfined compressive strength, effective porosity, abrasion characteristics, and impact potential, we can determine one or more optimal bit types and their specific applications. With this information, we can select the most suitable bit design, customizing features like cutter material and bit profile to match the formation conditions. Additionally, optimizing drilling parameters, such as weight on bit, rotary speed, and flow rate, further improves overall performance, leading to more efficient drilling operations and reducing bit trips to complete the section. Given that the wells in this application have long lateral sections, understanding the formation complexity along these laterals is crucial. This knowledge enables the implementation of geo-steering, ensuring the well stays in the optimal zone for maximum performance. As a result, this approach leads to faster well delivery times and an increased number of wells drilled annually.