A Workflow to Assess the Effect of Lateral Landing, Completion, and Fracturing on Production Potential in an Explorational Clastic Environment

Abstract

Three horizontal wells were drilled and completed with hydraulic fracturing in an explorational environment based on reservoir characterization from openhole logs. Limited success in establishing gas production rates showed the need for an integrated technical workflow to be applied for the next well, well-A. After good production results were achieved in well-A, the next phase used three more wells to correlate the production performance based on precise well placement. In well-A, openhole sampling was done during drilling of the pilot hole prior to sidetracking the lateral. This was followed by a novel fracturing approach with slickwater hybrid, low-polymer, and CO2 foamed treatments to study the effectiveness of treatments. Post-fracturing diagnostics including a production log and spectral noise log (SNL) were performed to assess production by stage. Three more wells were drilled in the same reservoir, and then a synthetic correlation model was built with resistivity logs to correlate precise lateral landing with the prolific sublayer. Finally, the production performance of all wells was studied based on well placement, fracturing, and the completion approach. The first phase of the study of the three wells allowed characterizing well-A in terms of reservoir interval, wellbore orientation, and fracturing strategy. Layer 1 was used to sidetrack the lateral. The post-fracturing production log and SNL indicated the CO2 foamed treatment was the best approach for well-A. The next three wells in the development phase were drilled in layer 1 with good production but inconsistent results. Because the highest flow rate in well-A was seen from the heel part of the lateral, an ultradeep resistivity-correlation bed boundary model was generated from well-A to characterize structural dip, and precise lateral locations were analyzed for all the wells. The model was also used to describe the most prolific sublayer within the layer 1 reservoir. The results showed a strong production dependence on the lateral landing with respect to the defined prolific sublayer. The number of fractures placed also showed a direct relation with gas rates. Finally, a geosteering simulation model was built to be used to further develop the area and detailed recommendations were documented. The ultradeep azimuthal resistivity tool has the capacity to detect ultradeep resistivity up to 100 ft from the borehole. Simultaneously, it can map ultrathin layers, which is necessary for the laminated reservoirs. The objectives of precise well placement and rendering productive gas wells in the exploration area through a comprehensive workflow was optimized and analyzed over 4 years. This paper presents systematic findings and a robust framework ready for implementation in future developments.