Fear not that no oil abounds yet....... Excellent article on Carbonate stimulation at http://www.slb.com/~/media/Files/resources/mearr/num8/51_63.pdf Just a small extract.... "When the productivity of a well in a carbonate reservoir decreases as a result of formation damage or low natural permeability, the production team will attempt to increase productivity through intervention and appropriate treatments. If they decide to workover the well, they must identify and implement a treatment program that creates conductive flow paths between the reservoir." This also applies to a new well as in HW3 ..
"Almost two-thirds of the world’s remaining oil reserves are contained in carbonate reservoirs. Carbonate formations tend to be extremely heterogeneous, with complex porosity and permeability variations, barriers, and irregular flow paths. Across the oil and gas industry, geologists, petrophysicists,and reservoir engineers are working to enhance their understanding of carbonate formations and reservoir behavior. There is a clear commercial focus to these research efforts; experience has shown that even small improvements in recovery methods can yield dramatic production results. Schlumberger is focusing its carbonate research and technology development on three critical areas: characterization, simulation, and stimulation. This article focuses on the last of these—increasing the productivity of carbonate reservoirs through better intervention and stimulation treatments. For many years, reservoir teams have sought to extend the useful lives of wells in carbonate reservoirs and to avoid early abandonment when productivity decreases as a result of formation damage or low natural permeability. In clastic reservoirs, a range of stimulation techniques can be applied with a high degree of confidence, and asset teams routinely intervene to create conductive flow paths. Although many of these standard stimulation methods can be applied in carbonate reservoirs, it may be difficult for engineers to predict how they will influence subsequent production.
A stimulating environment Acids play a key role in boosting production or increasing injectivity in oil and gas fields. Stimulation of carbonate rocks usually involves a reaction between an acid and the minerals calcite (CaCO3) or dolomite CaMg(CO3)2 that isintended to enhance the flow properties of the rock. Modern acid stimulation systems can be controlled and targeted to achieve specific aims for the asset team. Stimulation methods in carbonate sequences can be divided into two main groups: matrix treatments and acid fracturing treatments. Matrix stimulation involves pumping acids, solvents, or other treatment chemicals into the formation at less than the reservoir fracture pressure. When acids are introduced into a carbonate formation, some of the minerals in the rock dissolve, which creates intricate, high-permeability channels or wormholes (Fig. 1). Matrix treatments are often applied in zones with good natural permeability to counteract damage in the near-wellbore area. Acid fracturing stimulations, in contrast, are performed above the fracture pressure of the formation. A viscous pad (a fracturing fluid that does not contain proppant) is pumped into the formation at pressures above the fracture-initiation pressure, which fractures the rock. Then an acid stage is pumped to etch the fracture surfaces. The acid also creates conductive wormholes at or near the fracture surfaces. After stimulation, the fracture closes, but the increased conductivity between the formation and the well remains because of the etching and the creation of wormholes."
A lot more to do in this well if need be than just drill and hope it flows. If the oil is there they certainly will do all required to make it flow. The NEW methods of acid stimulation are doing wonders in many wells that stopped producing in Saudi Arabia.
JKA Price at posting:
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