Operational Benefits of Designing Acid-Soluble Drilling Fluids for Horizontal Wells in HTHP Conditions

Journal of Energy Resources Technology

Aljubran

et al. 2022

Managed pressure drilling (MPD) offers a closed loop circulation system in which formation fracture pressure, bottom hole pressure and pore pressure are managed at surface. The right choice of drilling fluid used during MPD operation facilitates correct mud management and treatment. Lab formulation and field trial of a high-density water-based drilling fluid comprising a mixture of barite (BaSO4) and manganese tetroxide (Mn3O4) as weighting agents has been described in the paper. Drilling fluids having a mixture of Mn3O4 and BaSO4 as weighting agents would have lower equivalent circulating density (ECD), better sag, better acid solubility and lower fluid cost as compared to conventional BaSO4 based fluids. This paper describes the formulation of three different water-based drilling fluids viz. 100, 120, and 150pcf drilling fluids having a mixture of Mn3O4 and BaSO4 and hot rolled at temperatures of 270, 250, and 300oF, respectively. Rheological properties, sag resistance and high pressure-high temperature (HPHT) filtration properties of the three fluids have been described in the paper. Data obtained from the field trial of 160pcf high density drilling fluids having a mixture of Mn3O4 and BaSO4 for wells with a 300oF bottom hole static temperature has been described. HPHT operations across naturally fractured formations with 0.51.0pcf drilling fluid window have been described in the paper. During the field trial, the fluid having a mixture of Mn3O4 and BaSO4 showed good rheological, filtration and sag properties thereby resulting in successful drilling of the well with no issues. MPD operation became more successful and practical with high density drilling fluids having a mixture of Mn3O4 and BaSO4 as it facilitated better drilling fluid management and treatment in comparison to conventional fluids.

High-Density Drilling Fluids for Managed Pressure Drilling: Lab Development and Field Trial

Journal of Energy Resources Technology

Aljubran

et al. 2022

Development and Field Trial of New Acid Soluble Drilling Fluids

Day 3 Tue, October 17, 2017

AlBahrani

et al. 2017

Stuck pipe, historically, has presented huge challenges to the worldwide oil industry. Stuck pipe has resulted in a great amount of nonproductive time, thereby causing huge monetary losses to the oil industry. A new drilling fluid has been designed, which employs a combination of two different weighting agents viz. barite and manganese tetroxide (Mn3O4) to overcome the problems linked with stuck pipe. Drilling fluids formulated with a combination of manganese tetroxide and barite as weighting agents are expected to have the following advantages: a) Better sag resistance, b) lower equivalent circulating density (ECD), c) lower fluid cost, and d) stuck pipe mitigation due to acid solubility of manganese tetroxide. This paper describes the formulation of 100 pcf and 150 pcf drilling fluids formulated with a combination of barite and Mn3O4 as weighting materials and hot rolled at 270°F and 300°F, respectively. The experimental work involves measuring rheological properties and high temperature, high pressure (HTHP) fluid loss at the specified temperature. Barite sag measurements were also performed on 150 pcf drilling fluids to determine the sag resistance of the fluid. The paper describes results of using different organic acid based filter-cake breaker fluids for the partial dissolution of Mn3O4 based filter cake. The paper also describes the data obtained from the field trial of 100 pcf and 155 pcf fluids formulated with barite and Mn3O4 for wells with a BHST of 290°F. The paper discusses the advantage of using such drilling fluids in mitigating stuck pipe issues and highlights their benefits in terms of better barite sag resistance and lower equivalent circulating density as compared to conventional drilling fluids formulated with barite as weighting agent. The 100 pcf and 150 pcf fluids showed superior rheology, thin filter cake and better sag resistance as compared to fluids formulated with only barite as the weighting agent. Different organic acids were able to partially dissolve the filter cake of drilling fluids formulated with barite and manganese tetroxide as weighting agents. This partial dissolution of filter cake is sufficient to free the pipe in the case of any stuck pipe event in the wellbore. The drilling fluids formulated with a combination of barite and manganese tetroxide showed good rheology, barite-sag resistance and resulted in successful drilling of wells having a BHST of 290°F.

Acid Soluble Drilling Fluids: Development and Field Trial

Day 3 Wed, November 15, 2017

AlBahrani

et al. 2017

Stuck pipe can not only significantly increase the cost of drilling but also has the potential to decrease the chances of successfully drilling a well within the stipulated time. A number of techniques and tools have been developed to solve the stuck pipe problem after they occur. However, the real objective should be to avoid the problem of stuck pipe to begin with and if and when they occur, the choice of treatment to release a stuck pipe should be such that it is not only cost effective but also quick. Such an objective prompted us to develop a new drilling fluid formulated with a combination of two different weighting agents, viz. barite and manganese tetroxide (Mn3O4). This paper describes the formulation of medium and high-density drilling fluids viz. 120 pcf and 150 pcf density fluids. These drilling fluids have been formulated with a combination of barite and Mn3O4 as weighting materials and hot rolled at 250°F and 300°F, respectively. After hot rolling these fluids at the specified temperatures, rheological properties and high temperature, high pressure (HTHP) fluid loss were measured. Sag resistance of the drilling fluids was estimated by perfoming static aging experiments in which the fluids were aged in inclined and vertical positions. To evaluate the filter-cake breaking potential of these mangansese tetroxide based drilling fluids, different breaker fluids were tested on the new 100pcf drilling fluid so as to calculate the % filter-cake removal efficiency. The paper also describes the data obtained from the field trial of 100 pcf and 145 pcf fluids formulated with barite and Mn3O4 for wells with a BHST of 290°F. The paper discusses the benefits of using drilling fluids formulated with barite and manganese tetroxide in mitigating stuck pipe issues and highlights their benefits in terms of better barite sag resistance and lower equivalent circulating density as compared to conventional drilling fluids formulated with 100% barite as weighting agent. The 120 pcf fluid when static agend showed superior rheology, thin filter cake and better sag resistance as compared to the 120pcf fluid formulated with only barite as the weighting agent. Different filter-cake breaker fluids have been showon to partially dissolve the filter cake of drilling fluids formulated with the acid-soluble manganese tetroxide as a weighting agent. This partial dissolution of filter cake is sufficient to free the pipe in the case of any stuck pipe event in the wellbore. The drilling fluids formulated with a combination of barite and manganese tetroxide showed good rheology, barite-sag resistance and resulted in successful drilling of wells having a BHST of 290°F.