Geology
Current Technologies Used for Data Acquisition in Drilling
As is known, oil and gas reservoirs vary by trap type, reservoir, rock formation, migration type, and cap rock. Based on this data, geologists determine the area of the territory, the thickness of the prospective reservoir rock, the expected porosity of the rock, the type of hydrocarbons present in the trap, and so on. The data for such reservoir assessments are obtained through well logging and subsequent interpretation.
At Petroleum's request, Measurement While Drilling Engineer Aigerim Raimbay will discuss the latest technologies for acquiring well logging data. Aigerim has been involved in drilling and evaluating many wells of varying complexity across different fields in Russia, Kazakhstan, Europe, and Africa. She will also share an example of how applied technology and its interpretation can prevent problems in future well construction operations.
Aigerim Raimbay studied corrosion control of in-field pipelines at the Kazakh National Technical University (now Satbayev University). Later, as part of her master’s degree, she researched the transport characteristics of proppants over rough surfaces during hydraulic fracturing at the University of Alberta. Upon returning to Kazakhstan, Aigerim actively engaged in geophysical surveys conducted during drilling, working on fields with various geological structures.


Aigerim notes that modern well logging technologies have advanced so significantly that high-quality reservoir evaluation data can now be obtained during drilling. This allows for drilling wells with precise target accuracy, commonly referred to as hitting the "sweet spot." This approach also saves time and, consequently, reduces costs associated with additional operations to mitigate potential issues. Logging while drilling (LWD) minimizes the risks of mechanical damage to the wellbore, reduces well instability, and prevents fishing operations caused by unsuccessful traditional logging procedures.
Another important factor is that traditional logging is not feasible in wells with a deviation angle greater than 45 degrees from vertical. In such cases, LWD is used in real-time, or the wellbore logging data is recorded (memory logging) to eliminate noise generated during drilling or to confirm real-time data.
According to Aigerim, geophysical measurements during drilling can provide a wide range of data for evaluating rock properties comparable to traditional geophysical surveys. Wellbore imaging can also determine bedding angles, faults, and fracture networks, which can assist in developing well completion strategies.

Figure 1. Expanded image of a section of the wellbore
Aigerim mentions that the primary data for reservoir evaluation during drilling include gamma ray logs (GR), resistivity (RT), density and porosity from gamma-gamma logs, and acoustic measurements such as shear and compressional waves. Additionally, high-resolution images can be utilized to assess wellbore quality, determine bedding angles, and more. Real-time logging data is compared with historical geological data from nearby wells, preliminary models, cuttings data, and other sources.
Aigerim shared an example of a wellbore imaging result (Figure 1) as one of the products of geophysical measurements during drilling.
Based on this example, Aigerim explained that the imaging data shows rock density, where the dark areas indicate high density and the light areas indicate low density. However, it is important to note that the bottomhole assembly (BHA) is cylindrical and rotates around its axis, meaning the sensor recording the data sometimes fits snugly against the wellbore wall and sometimes leaves gaps. This particular example clearly indicates that the wellbore has an elliptical cross-section.
Additionally, data from nearby wells and the evaluation of cuttings (such as rock type, shape, and other factors) are compared. Due to the non-standard wellbore shape, this information can impact casing running or the installation of lower completion equipment. Based on this data, the engineers involved in the project provide recommendations. These might include, for example, the need for additional wellbore conditioning operations (reaming), which can prevent casing running issues or optimize lower completion in the future.
According to Aigerim, this work is both fascinating and engaging. "At times, you feel like a detective," she says. "You gather all the data, compare it, and based on that, make technical decisions or provide recommendations to prevent future complications in operations."
Seidakhmetova S.
August 2024