Complex Perforation And Sand Control Technique

This paper describes a creative research and practice of a new technique-complex perforation and sand control on solving sand production problem in the oilfield .This technique combines three techniques of perforation sand control and armour-piercing into one and could perform the perforation and sand control in one operation. The main part of the technique is the complex perforator, which is consisted of a small long-radial ratio and large perforation diameter bullet and a front chamber filled with sand control material and propellant charge. During performance, a jet tunnel would firstly be formed right after bullet was fired, and meanwhile the propellant charge was ignited and created a high pressure that push the sand control material out of the front chamber in high jet velocity. The sand control material filled the tunnel and penetrated into the formation so as to form a sand retention shielding and thus realize the purpose of sand control. The complex perforation and sand control technique not only simplifies the operation procedure to a great extent, but also preserves the natural states of the oil wells, providing favorable conditions for later treatments, such as zonal water-injection, zonal acidizing and deplugging ,etc. It has solved some production problems encountered in present conventional oil well sand control techniques, for example: Mechanical sand -control outside casing is not only complicated in technical operation, but also causes difficulties in various stimulation measures and zonal treatment during the later life of oilfields. Besides the problem mentioned above, sand control inside casing reduces the inner drift diameter , which exerts influence on running in various down hole tools, and increases oil well skin factor and influences oil well productivity. Chemical sand control seriously damages formation and is easily affected by the complicacy within the formation. It has a low success ratio and it's effective period lasts shorter.This paper mainly focuses the statements on the design of the complex perforator. All the technical parameters of the complex perforator are mathematically derived by applying the theory of amour-piercing and mathematical model on the basis of theoretical analysis and research, a small long-radial ratio and large perforation diameter bullet and front chambers of the perforators are designed, proper sand control material are screened out ,make up ratio of the propellant charge is optimized, and complete structure of the complex perforator is finally being determined through the test.Owing to that the technical project and technique parameters of the complex perforation and sand control technique are evaluated and optimized to a considerable degree based upon the test, therefore, the paper describes the experimental target device designed according to API standard , and single shot and multi shot perforating gun modeling device simulated to the down hole condition.The complex perforating gun is the assembly suitable for satisfactory use with the multi shot complex perforator on site. The paper has investigated and discussed formation pressure and make up ratio between sand control material and propellant charge based on the different geological conditions; the development of different sized perforating guns for different oil wells; and finally formed three kinds of technical parameters and three models of serial products of perforating guns. Consequently , in order to examine the down hole sand control material packing condition, we designed and developed down hole pressure tester, through which the blasting condition of the down hole sand control material can be deduced recording the variation curves of pressure versus time during perforation operation.Then, this paper has analyzed the results. 7 well tests were performed on sites 1999 to 2000, and successful rate was 58%. Later, another 17 well tests were performed after improvement from 2001to 2002, and successful rate was increased to 94%, sand control was less than 0.03% in the oil wells...