This work provides a contribution to the positional tracking of the drill head in directional drilling considering real-time communication along the drill string. Particularly in the context of the development of oil and gas fields where target-oriented positions including the orientation of the drill head at large depths should be achieved. There are relatively large budgets available for such drilling projects to create suitable solutions using the latest technologies. In the construction industry, various deep drilling concepts are used, but with considerably lower depths. At the same time, high demands are also placed on position tracking. However, with these applications, lower technology budgets are available. Appropriate automatic measuring methods that provide online data in the process are not yet available even if the basic measurement technologies exist. An overall concept, which can meet the various requirements, is missing.
Regarding the scope of application, special attention is paid to the vertical drilling process used in Deep Soil Mixing. The Deep Soil Mixing process mixes the in-situ soil with cement or other binders to improve the mechanical and physical properties. This process results in a higher strength, lower permeability and low compressibility of the original soil [1-2]. Based on these systemic constraints, a new model is being developed and validated for the acquisition of sensor data and communication in the soil along the drill string and in real time during the drilling process (MWD). Based on the geometric model of the drill string, the signal model is developed to provide precise navigation data along the entire drill string. With the help of a new communication technology and the signal model, it is investigated which implementation concepts are possible and which performance is generated in each case. To provide a suitable reference, an error model is used, which has been defined by the Industry Steering Committee for Wellbore Accuracy (ISCWA). This model is used as a uniform basis for evaluation to improve the overall accuracy with regard to the tracking of the drilling process.
The newly developed communication technology enables a new form of sensor data acquisition, data distribution and data fusing. Precision and stability can be significantly increased without increasing the cost of the technology. An important aspect here is the possibility of transporting sensor data in an ad-hoc sensor network in both directions along the drill string. This concept is also independent of the length of the drill string and thus also of the depth of a drilling operation to be achieved. The consequent use of navigation concepts and their optimized adaptation to the developed system model allows the acquisition of all position parameters of the drill head in directional drilling. The consistent use of known fault model specifications allows a deep analysis of the developed navigation concept with other known measuring technology components and different sensor platforms. The analysis of the realization platforms with data from field tests gives a further Impression of the practicability of the developed concept.