GEOMECHANICAL EFFECTS OF OILFIELD CHEMICALS ON SAND FAILURE IN RESERVOIR ROCKS

Sand failure has become a serious challenge in the oil and gas industry that if not properly handled can have a drastic effect on the production rate, cause downhole and subsea equipment damage and also increase the risk of catastrophic failure. The sand failure occurs when the formation stress exceeds the strength of the formation which is derived majorly from the natural material that cements the sand grain and cohesive forces. Sand failure leads to the production of formation sand at the same time the formation fluids are being produced as a result of the unconsolidated nature of the formation. Oilfield chemicals such as inhibitors, surfactant, biocide, stabilizer, depressants, retarders, scavengers, defoamers, demulsifier and stimulants are widely used in the oil and gas industry for a wide range of applications. However, the current industry approach to geomechanical evaluation and sand failure and production prediction of reservoir formation that has experienced significant application of these chemicals does not in any way take into consideration the potential weakening of the grain fabrics that may arise as a result of chemical-formation interaction. This work investigates the mechanisms of the effects of oilfield chemicals on the geomechanical strength of reservoir rocks (both conventional and non-conventional) using rock mechanical testing, analytical techniques and laboratory chemical injection. The results are expected to serve as a baseline for further study to quantify the effects of these chemicals on sand failure and production.