The main goal in stimulating shale formations is to maximize the reservoir contact with the hydraulic fracture face. In order to achieve this goal current practices include pumping low-viscosity fluids at high rates with small mesh proppant cycles. A novel approach was used in a well in the Eagle Ford shale to enhance the stimulated area. This technique, called "relax-a-frac", was developed by an operator/service company alliance during the exploration phase. Real-time microseismic hydraulic fracture monitoring (RT HFM) indicated that the conventional slickwater treatments were not providing adequate lateral coverage across the planned stage. To address this issue, controlled changes were made to the pumping schedule, and the effects were evaluated using RT HFM. The results indicated that relax-a-frac proved to be highly successful in increasing the estimated stimulated volume (ESV) in this formation and area.In relax-a-frac, a part of the stimulation treatment was pumped (usually pad plus proppant slugs), followed by an extended shutdown to relax the formation. Once the surface pressure reached a predetermined value, the treatment was resumed, as per program, with monitoring for microseismic activity. The microseismic activity observed during the second part of the treatment showed a significant increase compared to that of the first part, with improved lateral coverage. The resultant ESV increased significantly from this technique as compared to any other specific changes tried on these wells. Production log results from Well 1 showed a definitive correlation between production contribution and the ESV derived from HFM analysis. This paper documents that this novel approach more effectively stimulates the Eagle Ford shale when compared to the typical treatment designs. Conclusions from a detailed comparison of the well performance and its relation to the treatment design are included.

Mechanical descaling of iron sulfide scales in high angle non-monobore or horizontal open hole completion offer multifaceted challenges, especially when the reservoir is depleted. The history of the descaling program in carbonate gas wells in Saudi Arabia dates back to 2007. The program suffered several setbacks with operational complexities like stuck pipe, H2S generation (souring) during chemical dissolution and severe induced damage during reservoir isolation process. The depleted reservoir needs to be isolated to ensure full circulation during mechanical descaling process. The mechanical means of isolation with a bridge plug is not feasible due to the presence of FeS scale in the wellbore. The only isolation option available at the moment is CaCO3 chips bullheaded from the surface. Often the post-descaling and stimulation operation does not restore the original production, due to the heavy damage induced in the reservoir during isolation. This paper shares a successful descaling experience and best practices in a single lateral open hole well that was completed with 4-1/2-in tubing and 7-in liner, and had severe pressure depletion. A novel non-damaging visco-elastic surfactant based fluid was used to fill the open hole lateral and as base to support CaCO3 chips above it that prevented additional damage and allowed reservoir isolation for mechanical descaling, using high pressure coiled tubing and a jetting tool. A clean wellbore with no further induced damage made subsequent post-stimulation results very attractive. The paper also presents the production results of stimulation treatment performed after the descaling treatment.

This paper focuses on the evaluation of novel diversion technology based on self-degradable solids particulates that were applied in the complex carbonate reservoirs. The well performance results were compared in this paper between wells stimulated with novel and conventional diversion technologies as part of the evaluation. The continued dependence on fossil hydrocarbons and the need to increase oil and gas production present solider challenges to more effectively stimulate marginal reservoirs with cost effective and improved technologies. In carbonate reservoirs, this challenge to maximize production comes from the increase in the stimulated reservoir volume. Diversion techniques in acid stimulation treatment in carbonate reservoir plays a major role in improving the stimulated reservoir volume. A typical acid stimulation design includes the diverter stages in between acid stages with the objective of both temporarily plugging the stimulated intervals and directing the treatment fluids to other untreated intervals and enhancing far-field diversion. It is necessary that these diverting materials are completely degradable and non-damaging to the reservoir. High temperature, high stress, pressure depletion, sour environment, and heterogeneity make certain carbonate reservoirs very complex and several diversion techniques have been tested in complex carbonate reservoirs over the last decade. In fact, enhancement in diversion technique for carbonate reservoirs is continuously being explored by the local well stimulation network team. Because of extreme reservoir complexities and heterogeneities in multifaceted carbonate reservoirs, it is critical to select an appropriate diversion technique along with optimum acid blends to redirect stimulation fluids from treated intervals to untreated intervals. The post-stimulation high resolution temperature logs and productivity index analysis indicated that wells stimulated with a novel diversion technology exhibited enhanced production due to its ability to produce more uniform distribution of acid along the net pay intervals. The novel diversion technology consists of multi-modal, self-assembling, self-removing, and environmentally friendly particles, presented in dry solid form to provide quicker and stronger redirection of fluid-flow paths by using the particle-bridging technique and sealing-off the width near the fracture's tip. More effective stimulation is achieved by branching fractures from subsequent stages as a result of far-field diversion.

The strong performance of fibre reinforced concrete with the stepped introduction of glass and sisal fibre was evaluated. In this study, fibres as light reinforcements with varying percentages of 0, 0.25, 0.50, 0.75, 1.00, 1.25 and 1.5 by weight of concrete were added to M15 grade concrete. The water/cement mix proportions ratio was 0.6. Control specimens, such as cubes were cast and tested at 7, 14, 21 and 28 days respectively to determine the mechanical properties. Glass fibre resulted in the most workable mix as compared to the sisal fibre with the highest slump and compaction factor of 19.50 mm and 0.93 respectively on the addition of 0.25% fibre. The addition of glass and sisal fibres in plain concrete (control) up to 1% increases the strength of concrete while the addition of fibres content greater than 1% resulted in a reduction in the strength of concrete. The optimum glass and sisal fibre content was 1% with maximum compressive strength of 36.50 N/mm2 and 34.67 N/mm2 at 28 days respectively. The experimental study revealed that glass fibre was stronger than sisal fibre. Hence, the fibre content of 1% is recommended for use as light reinforcement in concrete.

The objective of this paper is to highlight first worldwide implementation of coiled tubing (CT) compatible self-degradable fiber laden diverter for matrix stimulation treatment using enhanced high rate fiber optic real time telemetry system. The self-degradable fiber laden diverter has been used in bullheading acid stimulation treatments aimed to maximize reservoir contact and enhance gas production. Recently, the physical properties of fiber has been re-engineered enabling them to be pumped down coiled tubing to enhance diversion and stimulation effectiveness. Coiled tubing with fiber optic real-time telemetry has been utilized for many years in Saudi Arabia for matrix stimulation treatments and well interventions as it provides real-time bottom-hole parameters such as pressure, temperature, casing collar locator, gamma ray, tension and compression as well as distributed temperature sensing (DTS) to optimize fluid placement. The successes achieved with previously used 2 1/8-in. bottom-hole assembly (BHA) for coiled tubing with real time telemetry system offered the maximum rate of 2.0 barrel per minute (bpm), whereas this rate became a limitation to achieve the desired fiber concentration for diversion when fiber laden fluids were used. The low rate provision by 2 1/8-in. BHA led to the need of a new generation high rate 3.25-in. BHA to be used for coiled tubing fiber optic real-time telemetry system that can enable higher pumping rates, help in achieving the desired fiber concentration. For the first time in Saudi Arabian Carbonate reservoir, the novel fiber laden diverter was used during matrix stimulation treatment through 180 ft. perforated interval with new generation 3.25-in. bottom hole assembly (BHA) for coiled tubing fiber optic real-time telemetry system. The DTS used with the new generation coiled tubing high rate fiber optic real-time telemetry system helped in pre- and posttreatment evaluation. After successful high pressure coiled tubing stimulation using self-degradable fiber laden diverter with visco-elastic surfactant based acid system, the well performance exceeded expectation. The encouraging result was achieved by uniform stimulation coverage throughout the long perforation interval. The operation also proved the feasibility of using the new generation of fiber optic real-time telemetry system in challenging environment.