Development of Advanced Field Optimisation Techniques in Karachaganak Integrated Asset Model

Abstract

This paper presents the recent developments that have been achieved to improve the Karachaganak Integrated Asset Model (IAM). In 2014, SPE-172330 showed a step change in the application of integrated modelling techniques to this complex field and demonstrated the significant value of integration compared to standalone techniques. The complexity of modelling and integration is driven by more than 120 operating wells (production and injection), a complex gathering system, multiple processing facilities and multiple export lines, combined with gas reinjection for reservoir pressure support. To correctly capture real operations, the model requires layers of constraints at well, facility and export levels and an appropriate line-up of wells to maximise field oil and gas production. The model has been used to evaluate multiple field development projects with intensive capital investment worth several billions of US dollars. Hence, it is critical to ensure that the model is robust and replicates the reality. The latest improvements presented in this paper include a description of a more enhanced field optimisation approach that fulfills oil and gas export as well as gas reinjection targets whilst respecting all of the field constraints. Optimising such a complex problem is a challenging task considering the number of variables and constraints in the system. Production well ranking for line-up selection has also been improved. Rather than following a single approach of well prioritisation, for example by well Gas/Oil ratio to maximise liquid production, in the new methodology wells are smartly picked to fulfill all export and gas injection targets. Another improvement in the model was converting the optimisation logic, which was previously based on scripts, into open and transparent workflows using Visual Workflows in Resolve (application for connecting and running integrated models). This approach made it possible for Engineers to read, modify and extend the logic without having programming skills, bringing flexibility and sustainability into the model. Several case studies of actual project evaluations using the improved Integrated Asset Model will also be discussed. These studies highlight the key results, the importance of the implemented improvements for decision-making and how these affect the bottom line of projects.