Sand Control during Drilling, Perforation, Completion and Production

摘要

Sand control has been a challenge to the petroleumindustry since oil and gas was produced from weaklycemented sandstone formations. Several techniques have beenapplied; 1) restricted (critical) production rate, 2) screenand/or gravel packing, 3) sand consolidation, 4) FracPacking,5) oriented and/or selective perforation, and 6) combination ofany of the above.Sand formations may fail in compression, tension, andcohesion that trigger sand production. The compressive failureoccurs during drilling where the rock cannot withstand thenew stress field and/or the cementation materials havedeteriorated from mud filtrate exposure. The calculation ofmud weight to prevent compressive failure will be presentedin this paper. Additionally the failed zone is usually orientedin the direction of minimum horizontal stress which can beavoided during perforation by orienting the perforation tunnelsin the direction of maximum horizontal stress. Duringcompletion the cementation materials should be protectedfrom completion fluids. During production a pressuredrawdown is established for a given production rate. Thispressure drawdown may cause rock failure in tension orcohesion (erosion) leading to sand production. The nearwellborepressure is caused by skin damage due to reducedpermeability, stressed region, convergence flow, and partialpenetration. This paper presents a model to determine thecritical pressure drawdown based on relating the near-wellborepressure drawdown to the tensile and cohesive strengths of theformation. Hydraulic fracturing, referred to as FracPack, maybe applied to alleviate the near-wellbore pressure drawdownbelow the critical value that causes sand failure. Two fractureparameters are designed to achieve this goal; fracture lengthand fracture conductivity. This paper presents a designcriterion to determine these parameters to optimize a FracPackdesign for sand control. Examples from a field in Saudi Arabia will be used tovalidate the application of controlling sand production usingscreenless FracPack completion. In these wells a FracPacktreatment alone controls sand production. The multirate testused in these wells and the FracPack design for fracturingtreatments will be presented.