Hydraulic fracturing has been a key technology enabler for the development of tight gas formations in Oman. This tight gas accumulation has been developed with the supported of vertical wells, fractured at different depth covering up to 10 different hydrocarbons units. The intrinsic geomechanical, petrophysical and lithological heterogeneities of this tight units impact not only the fracture conductivity distribution but the drainage efficiency of the fractured zones, this is observed as mobility variations across this unit impact their contributions once all become commingle, with the areas of higher mobility dominating the total gas well production. It was anticipated that depletion of the higher mobility units will impact and change the contribution dynamics of the commingle production. However, this is only one dimension of the challenges to be considered as part of the hydraulic fracture strategy during the field development. This paper will be focus key operational challenges and the fundamental formation characterization requirements to assess in-situ stress dynamic variations during the life of the field; incorporating formation pressure points as integral part of the drilling program and in-situ stress measurements supported by wellbore stability evaluation and mini-fracture operations. It will be presented how variations on pressure and stress profiles, as the field developed, will impact the perforation and fracture strategies as well as pressure operating envelop to assure well integrity. It will be described the logging requirements as well as the lab characterization needed to determine key elastic properties to assess the hydraulic requirements for fracturing individual units or combination of them. It will be discussed how increase of pressure confinement potentially affects the in-situ elastic properties as depletion is experienced on specific gas units, inducing alterations on stress profiles that impact fracture propagation and final conductivity distribution. The use of radioactive tracers in combination with production logging were implemented to assess containment and fracture prediction, providing this an essential tool to determine fracture propagation behavior, deployment strategy and final conductivity distribution. Key operations covering plug milling, post fracture clean out and well lifting will be also discussed. Finally, it will presented key observation that can be implemented as part of methodologies used for fracture deployment on differential depletion formation, this leading to optimum field development while maximize investment.

Saih Rawl gas is located in the South Oman Salt Basin. There are two main formations targeted for gas production; Barik & Miqrat Formations. These formations are tight and exhibit low permeability. In order to enhance gas production, these formations have to be hydraulically stimulated. The main objectives of this paper is to demonstrate the petrophysical properties of the hydraulically fractured zones. Assess gas flow contribution thru the individual zones measured by production logging and comparing with the amount of proppant placed in the formation. In addition, the paper discusses reservoir properties and characteristics obtained from logging, post stimulation operations results and post stimulation gas production. The paper discusses 20 wells; 10 from the crest and 10 from the flank. The two formations Barik and Miqrat cover approximately 17 sub reservoir units. The total overall placement ratio is 95% and 78% for the crest and flank respectively with 156 hydraulic stimulation stages. It was observed that five sub reservoir units proved to be challenging to place the desired proppant. The maximum operating pressure is reached before achieving the desired proppant concentration leading to a screen out; concentrations of 2 – 3 pounds per gallon. Petrophysical evaluation of porosity and permeability cross plots showed a linear relationship in the wells in the crest. While there was no clear relationship was seen in the flank. Radioactive tracers used are to understand if there is any proppant propergation into the higher or lower zones. Not all the five challenging sub reservoir units showed propergation to other units. The wells located in the crest showed a better production rate as compared to the flank. The paper highlights the importance of the using petrophysical evaluation to optimize hydraulic fracturing design for successful operations.