Methods of PerforatingBullet Perforators • The first perforating gun; developed in 1932. • Fired a projectile (bullet) through the casing, cement, and into the formation to create a flow path from the formation into the casing. • Provides very uniform hole in the casing. • Became less effective as well depths required higher strength casing. • The bullet posed problems with plugging. • Still in limited use today. Shaped Charges Shaped Charges . Explosive Powder Chemical compound RDX HMX PYX . Charge Liners . Shaped Charge . Types of Perforators • Body copy for slides . guns with large charges for maximum performance • Perforating cost may be lower that other methods Disadvantages • Perforating must be done in balanced or overbalanced conditions for safety • Perforator length is limited to lubricator length .Wireline Casing Guns Advantage • Large O.D. Wireline Casing Gun (cont.) • Well control is dependent on lubricator sealing system • Well deviation increases time and difficulty in perforating .) Disadvantages (cont. Through Tubing Perforating Patented by Exxon in 1953 Patent purchased by Schlumberger Advantages • Allows limited underbalance to formation • Underbalance provides perforation cleanup • Better well control due to packer and tubing in place during perforating • Packer and completion/DST tools in well when perforating . Through Tubing Perforating (cont.) Disadvantages • Small O. guns with small charges have limited performance • Guns are often decentralized to optimize performance • Underbalance generally limited to 1000 psi • Perforator length limited to lubricator length .D. ) Disadvantages • Surface well control limited by lubricator seal system • Underbalance only available on first run in well • Wire may be difficult to maintain seal while pulling out of hole • Special pressure sealing equipment is necessary when SITP is high .Through Tubing Perforating (cont. D.Tubing Conveyed Perforating Advantage • Large O. guns with large charges for maximum performance • Optimum well control • Unlimited underbalance • No limits on well deviation • No limits on overall length • Surface safety is enhanced by use of nonelectric detonators and no fire devices . coiled tubing.Tubing Conveyed Perforating Advantage (cont. slickline or wireline • Rig is not always required • Multiple zones can be perforated selectively • Saves rig cost on long intervals • Multiple completion/test methods can be utilized .) • Guns are fired mechanically or hydraulically • Can be deployed on conventional tubing. . • Misfires can be more costly to correct if guns are attached to tubing.Tubing Conveyed Perforating Disadvantages • Have to change customer’s perception of cost from single service cost to overall completion cost. • Have to relieve customer’s safety concern’s. What You Want . What You Get . Getting What You Want Underbalance perforating • Use sufficient underbalance to back flush perforating debris and damage into the tubing and up to surface • Available underbalance is limited to formation pressure • Maximum usable underbalance is determined by formation matrix and mechanical systems of the well • Proper underbalance will maximize production . Getting What You Want Extreme Overbalance Perforating (EOB) • Apply extreme overbalance pressure to tubing or wellbore while firing the perforating gun • Will frac through the perforating damage and damaged zone into virgin formation • Extreme overbalance pressures range from 1.2 psi/ft • Typical to see the same production results as with underbalance perforating • More expensive than underbalance perforating .4 to 2. Getting What You Want A Typical Tubing Conveyed Overbalanced Perforating Well Configuration Gas And /Or Liquid Pumpers Gas Pressure In Wellbore Liquid Over Perforation Interval Pay Zone Damaged Zone . Getting What You Want Power Perf • Provides scouring agent (bauxite) near the perforations • Pumping during/immediately after perforating process forces bauxite into perf tunnels to aid in clean up • Bauxite aids in removal of perforating debris and compacted zone • Normally run in conjunction with EOB and/or Stimgun . Small tubing punch charges allow Proppant to leave carrier but fail to damage other tubular. .Getting What You Want Power Perf Proppant Placement • Proppant is displaced by Nitrogen and fluid into formation following detonation. large pressure at the perforations • Pressure provides near well bore stimulation creating fractures throughout the formation • Reduces injection pressures for further stimulation • Can be used in conjunction with EOB and PowerPerf .Getting What You Want STIMGUN • Propellant sleeve is installed over standard perforating gun • Sleeve is ignited when guns fire and produces a rapid. Getting What You Want “StimGun ” Assembly TM Conventional Perforating Carrier System Modified Charge Designs Outer Propellant Cylinder Designed to Break in Known Sections . Getting What You Want Preparing the StimGun . StimGun • The propellant is positioned and fired over the completion interval. • As the propellant burns it produces a pressure load on the formation below the formation rock’s compressive yield strength. . Getting What You Want StimGun • As the propellant burn pressure increases strain energy is accumulated in the rock matrix until the circumferential stress around the wellbore exceeds the strength of the rock. . • At this point fracturing occurs. Getting What You Want StimGun • Fracture volume is increased by continued gas generation from the progressive burn front of the propellant. . • Burn duration averages 12 ms. Questions? .