This paper describes a coiled tubing milling operation using fiber optic enabled coiled tubing and downhole tools for real time depth control and downhole monitoring of critical parameters. A description of the technology used, the job design, tool selection and execution of the job, the challenges encountered during the operation and the successful outcome are presented and discussed in the paper. The case history presented in this paper marks the first time that this particular fiber optic technology had been applied during a milling job worldwide. Coiled tubing milling operations can be challenging when precise depth measurement is critical. For the case history discussed in this paper the operator needed access to the production liner below the end of tubing with a BHA with a larger outside diameter than the inside diameter of the nipple installed in the tail pipe of the tubing. It was necessary to mill out this nipple profile while ensuring that other completion accessories above the nipple, including the production packer, were not inadvertently milled or damaged. Therefore, accurate depth control during the milling process was essential. Depth control was obtained with the real-time fiber optic CCL measurements. In addition, real-time pressure and temperature measurements were available from the fiber optic enabled BHA to monitor the milling parameters. The latest fiber-optic technology for coiled tubing including modules for CCL, temperature and pressure was used for the first time during a milling job. The data recorded, transmitted and integrated with the data acquisition software, created the ability to customize and optimize well intervention in realtime, and ensured that the required depth control precision was obtained, with precise control on the downhole milling parameters to optimize the milling operation.

Hydraulic fracturing has been an essential part of the gas development program in Saudi Arabia. In particular, proppant fracturing treatments have increasingly grown in number in recent years, which provided an incentive to look for viable alternatives to imported proppants. A new hydraulic fracturing design that utilized local sand as nonstandard proppants was recently applied in gas wells producing from sandstone formations in Saudi Arabia. This paper presents the theory behind the new fracturing design and summarizes the main results and recommendations. Sand quality-control lab tests were required prior to using Saudi Arabian sand as a propping agent in fracturing gas wells. The sand samples were analyzed for particle sizes, bulk densities, and compressive strengths. Well selection to apply the fracturing stimulation was then made based on a geomechanical criterion for the reservoir rock and the well's production performance. The treatment design utilized a channel-fracturing technique where the solids used comprised of roughly 65% natural sand and 35% ceramic proppants. The results show successful placement of the fracturing treatment into the formation. Despite sand crushing, the data show reasonable stimulation results and productivity enhancements. A number of important findings were also realized based on the analysis of the production performance, the reservoir transient pressure data, and the recovered solids and liquids. The discussions shared in this work including analysis of field data yielded important findings and recommendations. Particularly, the concept of applying nonstandard proppants, such as silica sand for hydraulic fracturing treatments is proven feasible. Overall, the new fracturing technique shows considerable potentials for sufficient process optimization and utilization of abundant resources in production operations.

Openhole multistage fracturing (OH MSF) completions consisting of openhole packers and ball-activated sleeves have become common to maximize reservoir contact in carbonate formations in Saudi Arabia. However, multiple cases have experienced communication between stages while performing acid fracturing treatments, caused by leaks at the openhole isolation packers. Consequently, sizeable portions of the target reservoir remain unstimulated. The loss of isolation between stages can be detected during ball landing, followed by an injection test in the subsequent zone. When treating pressure remains essentially the same as before, and after landing the stage ball, the treating fluid is likely bypassing the openhole packer into the previously stimulated interval. To solve this problem, a small volume of fluid carrying degradable multimodal particles and fibers have been pumped at a low rate ahead of the acid fracturing treatment to stop fluid flowing behind the packers. Subsequent treating fluids are injected into the intended interval, thus evenly stimulating the entire lateral. It was observed that when the pill arrived at the leak, pressure built rapidly, indicating effective bridging of the concentrated particulate pill. The total pressure increase was evaluated to confirm the performance of the pill material and that stage isolation had been restored. Afterward, pressure behavior during the acid fracturing treatments indicated that a new fracture was created in the target openhole interval. In several cases, the pill sustained more than 5,600-psi pressure buildup to successfully plug the leaks. Also, all materials used to form the pill are fully degradable, and no damage is left in the formation. Therefore, the entire wellbore is effectively stimulated with improved reservoir contact, resulting in higher production rates and enhanced reservoir drainage. Degradable particulate diverters have been widely used in recent years as an effective way to increase stimulated rock volume by diverting at the fracturing face in the near-wellbore region. The cases described in this paper show the first application of this technology as temporary isolation to mitigate interstage communication inside the wellbore.