Improving North Sea Fracturing and Stimulation Economics Through Increasing Innovation and Efficiency in Operations and Applications: Lessons Learned

Abstract

Completion and intervention costs across the North Sea are at an all-time high and continue to challenge development economics; this has been exacerbated recently by a deteriorating oil price making costeffective completion and intervention operations even more challenging. Typically at times such as these, the industry turns to the fracturing and stimulation process to maximise the return from existing assets and new wellbores. While this method continues to be feasible, increasingly this can only be achieved through challenging existing conventions and applying increasingly innovative approaches to the principal aspects and assumptions applied to the operations themselves; namely the deployment and the effectiveness of such operations in the field.As the cost of a fracturing and stimulation execution mounts, due to numerous factors, including the efficiency of the service itself, available/economic well intervention capability, provision of sufficient accommodation (somewhat surprisingly/unhelpfully) and an ability to flow-back and clean-up in an efficient and effective manner. This paper will provide examples and case histories, across a number of our North Sea operations, which challenge and optimise each of these areas and demonstrate a number of mechanisms and approaches that have successfully been applied in order to reduce overall costs.Some of the examples include a case history of the use of a boat (stimulation vessel) to boat (intervention vessel) stimulation approach, in order to eliminate secondary rig costs and thereby maximise the economics. Consideration of the use of a rig-based stimulation capability vs. extensive boat operations, efficient and cost effective well recompletion approaches and a suite of incremental improvements born out of continued North American solution development and deployment, such as the use of expandable packers and ball-drop matrix stimulations. Increasing the effectiveness of fracturing and stimulation (and maximising the productivity of each and every individual wellbore) is an obvious approach to improving economics and can be achieved in any number of ways. Again this paper will present a suite of examples and case histories of where this has already been achieved, across a number of our North Sea operations.The current 'perfect storm', of a low oil-price environment combined with high industry contractual costs, is forcing all operators to become increasingly innovative in their pursuit of economic resource development across the North Sea. This paper presents a number of examples of innovation and cost-saving approaches that have been employed in order to achieve such economic intervention and provide further insight into the additional development potential and opportunity that may exist across this varied asset base.

StressCage and Frac Pack: Drilling the Conventionally Undrillable Without Creating the Unfraccable

“…In late 2013 these treatments were performed (Ishteiwy et al, 2016) and the results can be seen in Table 1. It was surmised that the use of StressCage had resulted in substantial near wellbore formation damage, and, therefore, a suite of acid, diversion and scouring stages would be able to address this.…”

Investigation on the mechanism of hydraulic fracture propagation and fracture geometry control in tight heterogeneous glutenites

“…Therefore, it is necessary to achieve design goals through optimizing operating procedures. Ishteiwy et al (2016) indicated that creative operational solutions must be constantly sought to facilitate the development of increasingly difficult reserves through stimulation operations. However, there are currently few relevant explanations to reveal the mechanism of HF geometry control and elaborate on how to formulate an optimal injection strategy to maximize SRV for tight heterogeneous glutenites.…”