Innovational Techniques in Utilizing Real-Time Downhole Pressure and Distributed Temperature Surveying for Skin Quantification during Matrix Stimulation in Complex Multilateral Well in Saudi

摘要

This paper describes an innovative workflow for well intervention in a complex multilateral well, not only for accessing each lateral, but also to quantitatively evaluate matrix treatment in real-time for each lateral independently. The quantitative evaluation is based on two simultaneous criterions. The first is derived from the downhole pressure diagnostic plot (pressure transient analysis) in real time using the data acquired by the downhole real time gauge. The second is an estimate of the zonal coverage from the temperature profile plot before, while, and after pumping a treatment. Pressure transient analysis gives the skin as a direct output, and the cooling down/warming up distributed temperature sensing profiles identify where the treatment fluids went into the formation. This approach of combining well testing analysis techniques throughout the treatment in combination with zone coverage evaluation is strongly recommended for horizontal and complex wells, either clastic or non-clastic rocks. Basically, deriving the skin from the injectivity test (pre-treatment) and the skin from the post flush (post-treatment) will give an accurate as well as confident result when evaluating matrix treatments. In a field case, a comparison of the formation damage skin before and after the treatment was performed on the spot, and an improvement of eight times in injectivity was achieved with nearly uniform distribution of treatment fluids across five well laterals. Following the state-of-the-art procedures proposed and executed in this well, we were able to combine different technologies and techniques, which provided measurable cost reduction. The application of the technique will lead to eliminating confusion in accessing well laterals, quantifying the formation damage improvement in real time, eliminating the nonuniform distribution of treatment, optimizing diversion design/placement, and the ability to make treatment changes on the spot.