Formation Damage due to Drilling and Fracturing Fluids and Its Solution for Tight Naturally Fractured Sandstone Reservoirs

Abstract

Drilling and fracturing fluids can interact with reservoir rock and cause formation damage that impedes hydrocarbon production. Tight sandstone reservoir with well-developed natural fractures has a complex pore structure where pores and pore throats have a wide range of diameters; formation damage in such type of reservoir can be complicated and severe. Reservoir rock samples with a wide range of fracture widths are tested through a multistep coreflood platform, where formation damage caused by the drilling and/or fracturing fluid is quantitatively evaluated and systematically studied. To further mitigate this damage, an acidic treating fluid is screened and evaluated using the same coreflood platform. Experimental results indicate that the drilling fluid causes the major damage, and the chosen treating fluid can enhance rock permeability both effectively and efficiently at least at the room temperature with the overburden pressure.

Investigation of Slickwater Effect on Permeability of Gas Shale from Longmaxi Formation

“…The permeability reduction of shale samples and its effect on gas well production have attracted much attention in recent years. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]32 Song et al 33 evaluated the influence of polymer on the permeability reduction to gas and water by using shale fracture models with different fracture widths. The polymer resisted gas flow less than water flow in the microfracture.…”

Assessment of oil-producing wells by means of stimulation approach through matrix acidizing: a case study in the Azraq region

“…Two major well-acidizing approaches are often applicable for curing damage around the wellbore, namely, matrix acidizing and acid fracturing (Civan 2007;Bale et al 2010;Morsy et al 2013;Liang et al 2017;Leung and Mahmud 2019). The matrix acidizing process is a chemical stimulation technique that involves the injection of acid mixtures below the fracture pressures of rocks near the wellbore.…”

“…Its purpose is dissolving sediments to reinforce rock permeability and the establishment of a clean zone within the reservoir, thus eliminating the restrictions for oil flux into the wellbore zone. Commonly, matrix acidizing is applied in case of tighter carbonate and sandstone formations; it is recommended in industry to utilize acids with mass concentrations, in the range of 10-15%, while acid fracturing is implemented in case of carbonate formations (Bale et al 2010;Li et al 2015;Liang et al 2017;Kolin et al and Kurevija et al 2018) with relatively higher acid mass concentrations, in the range of 20-30%. This method involves acid injection to create channels or so-called wormholes, as the resulting rock fractures, under pressure from the hydrocarbons, might immigrate through.…”

Formation protection method of oil‐based drilling fluid for deep fractured tight gas reservoir

“…A few systematic studies rarely consider the comprehensive effects of multiple factors 13‐15 . On the other hand, the existing research generally selects specific materials directly to carry out experiments, lacking pertinence, indoor evaluation is difficult to fully consider the formation factors 16‐20 . At present, the primary task of deep/ultra‐deep well drilling is to ensure the smooth completion of the operation.…”

“…[13][14][15] On the other hand, the existing research generally selects specific materials directly to carry out experiments, lacking pertinence, indoor evaluation is difficult to fully consider the formation factors. [16][17][18][19][20] At present, the primary task of deep/ ultra-deep well drilling is to ensure the smooth completion of the operation. Reservoir protection has been widely proposed, but it has not received much attention.…”