Underbalanced Drilling (UBD) (TRL 8-9):
UBD was trialed in ADCO in 2010-2011 in 4 wells. The trial was very successful with significant improvements in productivity (almost an order of magnitude increase in Productivity Index!) and on-bottom ROP. Due to the sustainable production improvements obtained and the reservoir characterization benefits, the need to progress and expand this technology gained widespread support in ADCO. A new UBD campaign kicked off in Q4, 2015 for a minimum of 20 wells. Trials are planned to determine optimum horizontal well lengths. In addition, it is also planned to conduct Real Time Reservoir Characterization (RTRC) to maximise the benefits from this technology.
Underbalanced Coiled Tubing Drilling (TRL 6-9)
The feasibility of conducting Underbalanced Coiled Tubing Drilling has been matured in the Gas Asset and a number of potential candidates have been identified. Studies are ongoing to determine whether gas recovery can be improved in specific reservoirs. The initial studies have been completed and potential candidates were identified. The candidates are currently being screened to determine benefits in gas recovery in specific reservoirs by adding lateral branches of up to 1,500 ft. to existing wells. If a robust business case can be determined, this technology will be pursued further.
Integrated Pad Drilling (TRL 7-9):
ADCO’s major fields are becoming more congested with wells and facilities as field developments progress. As a result, Asset Master Plans continue to be optimized to determine optimal well spacing and surface facility designs and to ensure the most cost effective, life cycle operational performance. Deployment of Integrated Pad Drilling is already underway and is now considered the optimum way forward for drilling developments in all Assets.
Horizontal Well Length and Completions (TRL 8-9):
The objective of deploying advanced well designs, like long horizontals or Maximum Reservoir Contact (MRC) wells is to minimize the number of wells in the field, hence reducing CAPEX, surface hook ups and overall field footprint. In addition, these wells should also accelerate recovery and maximize production. A further advantage could be to improve productivity/injectivity and therefore the areal sweep efficiency in tight reservoirs. ADCO is therefore evaluating the benefits of advanced well designs on well rates, sweep efficiency etc, to determine the wider scope for these wells in our reservoirs. Any new procedures/equipment required to enable successful installation of these wells is also being investigated and an implementation plan developed starting with 10,000ft long horizontal wells in some reservoirs and then expanding them to other fields.
Studies are currently ongoing to determine the long term value to ADCO of these long horizontal wells, as quite a number have already been drilled and completed. The incremental production and injectivity of wells greater than 6,000 ft, as well as the pros and cons with respect to well accessibility, logging constraints, field development plans and well completion options, needs to be verified. The data required to conduct a comprehensive review is currently being acquired. A definitive assessment of the value of these initial wells in ADCO will be concluded in 2016.
Furthermore, the business benefits of various completion technologies are also being evaluated in ADCO. For example, wellbore segmentation can delay water/gas breakthrough, improve sweep and increase recovery, improve well clean up and improve horizontal well accessibility. Work is therefore ongoing to evaluate our -75 segmented wellbores, which contain swell packers and Interval Control Devices (ICDs), to develop a long term strategy for all ADCO fields. Initial applications of ICDs in ADCO shows promise. New suppliers and products are continually entering the market and the next generation equipment is already being introduced and evaluated.
Advanced Stimulation Techniques (TRL 7-9):
On a yearly basis, over 300 wells are stimulated in ADCO to improve productivity/injectivity. Stimulation is required due to formation damage after drilling, damage that occurs during production/injection or uneven flow profiles along the wellbore in horizontal wells. ADCO is undertaking studies to define the extent of damage in each reservoir, to identify damage mechanisms and skin, and to evaluate different mechanical and chemical stimulation options such as Surgi-Frac, stim-tunelling, fishbones, dissolvine etc. In line with Shareholder recommendations, the option of fracing (both acid and hydraulic) is also being studied as it may prove to be beneficial in some of the tighter formations, in which conventional stimulation techniques have proven to be ineffective.